Producing Quality Compost

Transcription

1 Producing Quality Compost 2007 Third Edition Operation and management guide to support the consistent production of quality compost and products containing recycled organics

2 Recycled Organics Unit PO Box 6267 The University of New South Wales Sydney Australia 1466 Internet: Contact: Angus Campbell Copyright Recycled Organics Unit Third Edition. Second Edition, First Published This document is and shall remain the property of Recycled Organics Unit. The information contained in this document is provided by ROU in good faith but users should be aware that ROU is not responsible or liable for its use or application. The content is for information only. It should not be considered as any advice, warranty, or recommendation to any individual person or situation. ISBN COMMPOST N E W S O U T H W A L E S This package has undergone national peer review by a range of technical and industry experts (see acknowledgments) and has been endorsed by COMMPOST NSW and the NSW branch of the Waste Management Association of Australia.

3 Recycled Organics Unit PO Box 6267, UNSW, Sydney, Australia, Preface to the Producing Quality Compost Information Sheets The Producing Quality Compost series of Information Sheets have been produced to support the continuing development of the Recycled Organics (RO) industry in New South Wales though a greater focus on operation and management for quality. Work commissioned by Environment Australia (Environment Australia, 1999) 1 indicated that market acceleration for recycled organics products is dependent on the sale of quality products that meet the needs of specific market sectors. Since the publication of this report and the first edition of Producing Quality Compost (Recycled Organics Unit, 2001), significant progress has been made in developing markets for recycled organics products, with novel markets being developed in intensive agriculture (e.g. viticulture), a variety of large-scale landscaping projects and in urban stormwater treatment to mention a few. Greater adherence to process certification and product standards in the recycled organics sector is providing users with higher quality, fit for purpose products which can be used reliably for the intended application. Whilst certification against recognised product standards is increasing, industry-wide adoption of these standards will provide the market with an improved level of confidence in products being made available for sale, and potentially resulting in enhanced demand-side pull of product into the market. Clear product standards and adoption of these by the recycled organics industry is proving to be an important driver in allowing Local Government to select appropriate technologies and processes to convert compostable organic materials into saleable products, in a bid to increase the diversion of valuable organic matter from landfill. It is widely recognised that increased use of industry best practice guidelines and (currently) voluntary national product standards (e.g. those published by Standards Australia) will increase the quality of products manufactured from compostable organic materials. Increased product quality and better labeling to inform consumers as to how the products can be beneficially used will result in considerable market acceleration, and market penetration, into areas where recycled organics products are not traditionally used. Quality recycled organics products are manufactured when an organisation employs elements of best practice that is, strong process control to ensure that products manufactured conform to previously designed specifications and market requirements. Strong process control systems are based upon a number of key steps, including on-site monitoring and testing at all stages of production, and product testing by independent laboratories to confirm that a product meets specification. Process control is an integral part of a quality management system. A quality management system is a set of procedures an organisation establishes to guarantee it products will satisfy consumers. Thus, adoption of quality management and process control systems is needed to consistently produce quality recycled organics products that achieve consumer confidence and market satisfaction. 1 Environment Australia (1999). Environment Australia Organics Market Development Strategy. Report prepared for Environment Australia by Meinhardt (Vic) Pty Ltd, Strategic Multimedia, EC Sustainable Environment Consultants and Environment Resource Management (QLD) Pty Ltd. October Information for organic resource recovery, management, research & development, quality systems and training

4 Recycled Organics Unit PO Box 6267, UNSW, Sydney, Australia, Australian Standards for recycled organics products have been published for composts, soil conditioners and mulches, general and specialist potting mixes, general and specialist soils, and for products referred to as soft fall mulch which can be used for playground surfacing to reduce the extent of injuries suffered by children. Increased use of these product standards is necessary to improve the quality of recycled organics products that meet customer requirements on the market place, and to accelerate demand for these products. The second edition also contains updated references to Australian Standards AS 4454 (Composts, soil conditioners and mulches), AS 3743 (Potting mixes) and AS 4419 (Soils for landscaping and garden use), which have recently been updated. These Information Sheets have been developed to complement existing information resources and to provide an easy-to-read account of how a quality management system can be put in place in an organisation. It gives practical guidance to the development of an on-site testing program to maintain process control, and it also provides a simple overview of the key Australian Standards that are relevant to recycled organics products. It is hoped these Information Sheets will continue to assist industry to consistently produce quality, high value compost and products containing recycled organics that meet customer requirements. Please note that a competency-based training program is under development by the Institute for Horticultural Development and the Recycled Organics Unit in a number of areas relating to the issues addressed in Producing Quality Compost. Final details regarding training will be made available towards the end of 2002, and will be advertised on the Recycled Organics Unit s web site, Information for organic resource recovery, management, research & development, quality systems and training

5 1. Information Sheets in Producing Quality Compost This package contains a collection of eleven Information Sheets: Information Sheet No. 3-1: Striving for quality: basics of a quality management system Information Sheet No. 3-2: Quality assurance systems Information Sheet No. 3-3: On-site field testing and monitoring for quality Information Sheet No. 3-4: On-site laboratory testing for quality Information Sheet No. 3-5: Off-site testing for quality: recommended tests and how to select an independent laboratory Information Sheet No. 3-6: Quality of biosolids: risk minimisation during re-processing Information Sheet No. 3-7: Manufacturing quality products: introduction to Australian Standard AS/NZS for playground surfacing Information Sheet No. 3-8: Producing quality compost: introduction to Australian Standard AS composts, soil conditioners and mulches Information Sheet No. 3-9: Manufacturing quality products from compost: introduction to Australian Standard AS for potting mixes Information Sheet No. 3-10: Manufacturing quality products from compost: introduction to Australian Standard AS soils for landscaping and garden use Information Sheet No Sample management for consistent analysis of product quality 2. Who should read the Information Sheets? The package of Information Sheets has been developed for all stakeholders in the recycled organics sector who wish to gain a better knowledge of the key documents relating to quality management systems, industry best practice, and product standards that significantly influence product quality. More specifically, the package of Information Sheets have been developed for: prospective recycled organics product manufacturers; experienced manufacturers of products from compostable organic materials; manufacturers, blenders and suppliers of recycled organics products; marketing agencies; Resource NSW officers; Local Council waste management officers; Local Council planning and approvals officers; waste educators; relevant government policy makers; and industry consultants. Information for organic resource recovery, management, research & development, quality systems and training

6 3. Other Packages A series of eight packages are available on important aspects of recycled organics industry development. These are listed below. Package 1: Establishing a licensed composting facility; Package 2: Guide to developing a process control system for a composting facility; Package 3: Producing quality compost; Package 4: Guide to selecting, developing and marketing value-added recycled organics products; Package 5: Composting science for industry; Package 6: Buyers guide for recycled organics products Package 7: How to use recycled organics products; Package 8: Occupational health and safety and commercial composting. All of these packages are obtainable from 4. Terminology Terms used throughout this package of Information Sheets have been officially adopted by the NSW Waste Boards (now Resource NSW) in July 2000 in the form of the RO Dictionary and Thesaurus: Standard terminology for the New South Wales recycled organics industry, produced by the Recycled Organics Unit. This document is freely downloadable from 5. How to cite this publication This publication consists of a series of Information Sheets that are compiled into a set. When citing information from this publication, the set of Information Sheets must be cited (not individual Information Sheets), as shown below: Recycled Organics Unit (2003). Producing Quality Compost: Operation and management guide to support the consistent production of quality compost and products containing recycled organics. Third Edition. Recycled Organics Unit, internet publication: 6. Training Please note that an accompanying training program will be available soon on Producing Quality Compost, details of which can be found at our web site, Information for organic resource recovery, management, research & development, quality systems and training

7 7. Acknowledgements The authors would like to acknowledge all members of the peer review committee who have invested their valuable time in reading and providing feedback on this package. The following reviewers are graciously thanked for their contributions: Dr Trevor Gibson, Program Leader, Organic Waste Recycling Unit, NSW Agriculture. Dr Kevin Wilkinson, Program Leader, Institute for Horticultural Development, Agriculture Victoria. Mr Darren Bragg, Manager (Organics), Resource NSW. Dr Martin Line, Senior Lecturer, School of Agricultural Science, University of Tasmania. Dr Pam Pittaway, Soil Scientist, National Centre for Engineering in Agriculture, University of Southern Queensland. Mr Garry Kimble, Quality Assurance Services and [past] Chairman of COMMPOST NSW. Mr Chris Rochfort, Principal, EC Sustainable Environment Consultants. The committee of COMMPOST NSW. Information for organic resource recovery, management, research & development, quality systems and training

8 Information Sheet No. 3-1 Striving for Quality Basics of a quality management system 1 2 Information Sheet No. 3-1 Third Edition 2007 Inside This Sheet Quality defined What is a quality management system? The eight quality management principles Definitions Ten steps to quality management implementation 3 Three key documents in a quality management system 5 The importance of testing, monitoring and record keeping 6 Training in quality management systems Important references Acknowledgement Recycled Organics Unit 2003 ISBN Quality defined Quality refers to a product or service that is fit for purpose, conforms to requirements and within specification. Manufacturing and marketing of quality composts and products containing recycled organics of consistent quality is a key to gaining customer satisfaction and a continued market presence. Quality, however, is not only concerned with whether a product or service meets the claims made for it. Your customer s perceptions of your business is based on the product or service you deliver and on the dayto-day contact they have with you and your staff (QAS, 2000a). Quality embraces how you must meet all your customers requirements, which could include: how they are greeted on the telephone; the speed with which the salesperson responds to a request for a quotation; introducing new products and services when required; and even ensuring that the invoice is correct! Every contact with every customer on every occasion builds a picture of your company in the eyes of your customer. It is widely known that the successful operation of an organisation requires effective leadership and managing in a systematic and visible manner. This success can result from the implementation and maintenance of a quality management system that is designed to continually improve performance by addressing the needs of all interested parties (stakeholders) (QAS, 2000b). This Information Sheet reviews the basics of a quality management system and the important role it can play in a composting operation. This remainder of the Information Sheets in this series (3-2 to 3-11), however, focus more on the management of processing and production systems so products of consistent quality can be manufactured. What is a quality management system? A Quality Management System (QMS) is a term applied to a variety of tools that assist an organisation in managing and controlling its processes, inputs and outputs to meet customer requirements (QAS, 2000b). Composting and related operations produce products that are intended to achieve customer satisfaction. The International Standards Organisation (ISO) 9000:2000 family of QMS standards can assist organisations in achieving this objective. The QMS approach encourages organisations to analyse customer requirements, define the processes that provide product acceptable to the customer and to keep these processes under control. Because customers needs and expectations are changing, organisations are driven to Information for organic resource recovery, management, research & development, quality systems and training

9 continually improve their products, services and processes (QAS, 2000b). The benefits of implementing a quality management system include: consistency in service delivery and measurable service outcomes; continual improvement; employee involvement in the organisation s progress; and a marketing edge on competitors. Registration of an audited and certified QMS through a third party body (e.g. Quality Assurance Services) allows the organisation to mark their promotional material (not product) with a logo (e.g. five ticks logo as shown in Plate 1) demonstrating compliance to an international standard for quality (AS/NZS ISO 9000:2000). Plate 1. Quality endorsed company logo demonstrating compliance to a quality management system provided by Quality Assurance Services. This mark is but one of a number supplied by certification bodies under the Joint Accreditation Scheme of Australia and New Zealand (JAS-ANZ). Such logos are an effective marketing tool, showing customers that your organisation has a QMS in place, demonstrating the company s commitment to quality and capability of manufacturing products or supplying services that meet customers requirements. Please note that there are other registered bodies that can supply other marks of quality system certification under the Joint Accreditation Scheme of Australia and New Zealand (JAS-ANZ). The eight quality management principles Quality management standards (AS/NZS ISO 9000:2000 series) are based on eight quality management principles. These describe the way we work and are imbedded in what we do to achieve the organisation s goals and objectives. These principles are: 1. Customer focused organisation: Organisations depend on their customers and therefore should understand current and future needs, meet customer requirements and strive to exceed customer expectations. 2. Leadership: Leaders create and maintain the internal environment in which people can become fully involved in achieving the organisation s objectives; 3. Involvement of people: People at all levels are the essence of an organisation and their full involvement enables their abilities to be used for the organisation s benefit. 4. Process approach: A desired result is achieved more efficiently when related resources and activities are managed as a process; Definitions Quality Fitness for purpose; conformance to requirements; within specification. Quality Management System (QMS) A set of procedures an organisation establishes to guarantee it products will satisfy consumers. 5. System approach to management: Identifying, understanding and managing a system of interrelated processes for a given objective improves the organisation s effectiveness and efficiency; 6. Continual improvement: Continual improvement should be a permanent objective of the organisation; 7. Factual approach to decision making: Effective decisions are based on the analysis of data and information; and 8. Mutually beneficial supplier relationships: An organisation and its suppliers are interdependent, and a mutually beneficial relationship enhances the ability of both to create value (QAS, 2000b). Ten steps to quality management implementation It takes a great deal of time, effort and ability to develop and implement a QMS. Both executive commitment and the allocation of appropriate resources are essential if the task is to succeed

10 Experience has shown that in order to plan, develop and implement effective quality systems, every company should takes these 10 steps: 1. Appoint a person to be responsible for the implementation of the AS/NZS ISO 9000:2000 quality system. 2. Set up an implementation team. Representatives from all sections of the organisation should be members of the team. 3. Establish the objectives and plan for the implementation of the system. Important components include: implementation objectives, initial system review, the management plan and an implementation plan. 4. Create quality awareness. 5. Define responsibilities and organisational structure, including job descriptions and an organisation chart. 6. Develop a quality policy manual, describing management s intent concerning the documented quality management system. 7. Establish employee participation. 8. Prepare and implement procedures and/or work instructions, as well as a document control system. 9. Perform internal and external quality audits to assess the performance of the QMS; and 10. Review. The system needs to be periodically reviewed to ensure its continuing suitability and effectiveness (Figure 3) (QAS, 2000a, b). Three key documents in a quality management system There are three main documents which are needed to formalise a QMS. These are the: 1. Quality manual This is a high level document that describes management s intent concerning the documented quality management. It indicates to prospective parties the nature of the business activities undertaken to meet customer requirements. It is a road map of what an organisation has to offer in terms of quality to remain competitive in the market place. This document often contains: the quality policy; activities of the business; how the documentation system works; exclusions to AS/NZS ISO 9000:2000; statements of responsibility and authority; overview of business philosophy and history, and a description of the organisation s work processes and their interactions (QAS, 2000b). 2. Procedures manual Procedures describe in a simple way the controls which exist to ensure that all critical processes operate in such a way that both customer requirements and the requirements of AS/NZS ISO 9000:2000 are met. A procedure generally describes the purpose of the activity; how it operates; and the controls which reduce variability and ensure conforming output. An example procedure for accepting garden organics at the gate of a composting facility is shown in Figure Work instructions manual To avoid excessive documentation in the procedures manual, detailed steps required for each activity shown in the procedures manual can be written up into a work instructions manual. The work instruction manual does not need to be a large manual either. In many cases, work instructions may refer back to an equipment manual. The steps required to operate a ph meter, for example, may be appropriately addressed in the equipment manual which came with the device, or to a method documented in a standard. An example of a work instruction is shown in Figure 2. Please note that work instructions may be needed for other critical areas of a composting operation. These may include: transport, receipt, inspection, materials identification, visible contaminant removal, transfer and storage of raw materials; access, parking, unloading areas, vehicle cleaning facilities; pre-processing such as shredding, sorting, mixing, prewetting materials; composting, including facilities for mixing, turning, aerating, adding inorganic or organic amendments; managing odour and leachate, drainage and stormwater, storage, treatment, use or disposal of water and leachate; administration, maintenance and storage of plant, equipment and chemicals; security systems and fire fighting facilities (NSW DUAP, 1996).

11 Figure 1. A procedure for accepting garden organics at a composting facility. This is a critical activity that can have an impact on the composting operation if not properly controlled. WI refers to work instruction. Work instructions outline the detailed steps required for each activity. For the procedures manual, it is sufficient to identify the critical tasks and refer back to the work instructions for more detail (e.g. for training new staff)

12 Figure 2. An example of a work instruction for accepting and rejecting garden organics at the gate of a composting facility. Note that work instructions will differ depending on the type of operation. The example shown below is a step-by-step instruction for carrying out the accepting and rejecting procedure as detailed in Figure 1. WI NO: WI Page 1 of 1 WORK INSTRUCTION Method of Accepting and Rejecting Garden Organics at Gate ISSUE DATE REVIEW DATE 5/5/1999 5/5/2001 Work Instruction: accepting and rejecting garden organics at gate Accepting and Rejecting Batch If visual contamination is more than 5% (by volume), reject the batch and notify the driver that the garden organics cannot be accepted. Accept the batch if an alternative contractual arrangement has previously been made. See Contracts Folder (Gate Office, Zone 1) to confirm this. If visual contamination is less than 5% (by volume), notify driver that the batch will be accepted. Direct the driver towards the weighbridge and record the tare of the trailer or truck before contamination is removed. Refer to WI for further details. END The importance of testing, monitoring and record keeping The quality manual, procedures manual and work instructions manual outline how critical activities in your organisation are performed, and how they are maintained to ensure that products and/or services of consistent quality are produced and/or delivered. Figure 3. The Plan-Do-Check-Act cycle for continuous business improvement (QAS, 2000a). A vital component of a QMS is a testing and monitoring program to ensure that the systems in place are performing effectively. Note that appropriate testing and monitoring procedures for use at a composting facility are reviewed in Information Sheets 3-3, 3-4 and 3-5. The on-going performance of a QMS can be verified by having the system audited by a third party certification body

13 System fine-tuning, improved quality assurance and improved customer satisfaction can result from regular auditing of a company s QMS. Training in quality management systems A basic overview of QMSs and how they can apply to composting operations has been provided in this chapter. Advanced training in QMSs is provided by a number of organisations. A good starting point is Quality Assurance Services Pty Ltd, contactable on the internet at Notes: Important references AS/NZS ISO 9000 (2000). Quality Management Systems Fundamentals and Vocabulary. Standards Australia, Homebush, NSW. QAS (2000a). Implementing a Quality Management System. Training manual produced by Quality Assurance Services, New South Wales. QAS (2000b). Understanding the AS/NZS ISO 9000:2000 Standards. Training manual produced by Quality Assurances Services, New South Wales. NSW Department of Urban Affairs and Planning (1996). Composting and Related Facilities EIS Guideline. NSW Government Printing Service, Sydney, Australia. Acknowledgement The authors would like to extend a special thankyou to members of the peer review committee for critically evaluating this document: Dr Trevor Gibson, NSW Agriculture; Dr Kevin Wilkinson, Agriculture Victoria; Mr Darren Bragg, Resource NSW; Mr Garry Kimble, Quality Assurance Services; Dr Martin Line, University of Tasmania; Mr Chris Rochfort, EC Sustainable Environment Consultants and Dr Pam Pittaway, University of Southern Queensland. Recycled Organics Unit 2003 Produced by: Recycled Organics Unit PO Box 6267 The University of New South Wales Sydney Australia 1466 Online contact details: ROU Internet Angus Campbell Whilst all care is taken in the preparation of this Information Sheet, the information provided is essentially general in nature and the Recycled Organics Unit disclaims all liability for any error, loss or other consequence which may arise from application of the information in any specific situation.

14 Information Sheet No. 3-2 Quality Assurance Systems 1 Information Sheet No. 3-2 Third Edition 2007 Inside This Sheet What is quality assurance? Types of quality assurance systems 2 Definitions 3 Applying for QMS and/or product certification Important references Acknowledgement Recycled Organics Unit 2003 What is quality assurance? Quality assurance refers to a systematic pattern of all actions necessary to provide adequate confidence that the product optimally fulfils customers expectations. The risk to customers of purchasing inconsistent product, or a product not fit for purpose, or out of specification will vary depending on the type of quality system in place. Types of quality assurance systems In order to reduce the risk of purchasing a non-conforming or low quality product, the customer may require various levels of assessment of the supplier s Quality Management System (QMS). Additional indicators of quality may be provided to a customer by reporting that your product exceeds the minimum requirements for an industry or Australian Standard. There are four Australian Standards for products containing recycled organics, and these are listed below. These standards are reviewed in Information Sheet Nos. 3-7 to AS/NZS 4422 (1996). Playground surfacing specifications, requirements and test method; AS 4454 (2002). Composts, soil conditioners and mulches; AS 3743 (2002). Potting mixes; and Four commonly used methods of assessment are described below from most risky to least risky from the customer s point of view (more the better!). Self declaration This is a form of first party assessment. The manufacturer says that they make products of a certain quality, possibly with reference to an Australian Standard, for example. This can be adequate for many low risk products, but it depends on the reputation, integrity and image of the company in the market. This is the least desirable quality assurance system as product quality is not independently verified. Customer-supplier assessment This is a form of second party assessment. In this system, the customer audits the supplier s QMS with particular emphasis on the products the customer intends to buy. An excellent method if the customer has the resources and expertise to audit the supplier and the supplier is willing to subject their system and people to such audits. In general, this is an effective method as suppliers can be subjected to multiple audits and have technical resources tied up in these audits. From a customer s point of view they can generally be very confident that products meet their requirements. ISBN AS 4419 (2002). Soils for landscaping and garden use. Information for organic resource recovery, management, research & development, quality systems and training

15 Quality system certification This is a form of third party assessment. Quality system certification a process whereby a company s quality management system is assessed against international standards for quality such as the AS/NZS ISO 9000:2000 series of documents is an even better way of demonstrating the quality of a product. As described in Information Sheet No. 3-1, QMSs comprise a variety of tools that assist an organisation in managing and controlling its processes, inputs and outputs to meet customer requirements (QAS, 2000). This system ensures that the manufacturer has documented procedures in place to demonstrate capability to produce products to customer requirements, and to prevent unacceptable product being made at all stages of production. A regularly audited and registered QMS is a customer s assurance that products sold will meet their requirements. Please note that further details can be found in Information Sheet No Product certification This is a form of third party assessment. Although QMSs are a fundamental basis for consistently producing quality products, some customers may require additional evidence that a particular product conforms to a recognised national, international or industry product standard (e.g. AS for Composts, Soil Conditioners and Mulches). This is where a product certification system is required. Product certification is the best way a customer can be assured that they are buying a product of consistent quality that conforms to a recognised standard for quality. Companies that wish to apply for product certification need to have a QMS in place. The overall purpose of product certification is to ensure that the manufacturer can demonstrate that products can be consistently manufactured to a standard. The company s capability to manufacture a product to a particular standard is assessed by 'type testing'. That is, a representative sample of product is independently selected and sent to an independent, recognised laboratory for testing. To confirm that the manufacturer is able to demonstrate that products can be manufactured to a standard, regular auditing of the manufacturer s QMS relevant to the production of the product is also necessary. Companies that have a QMS and manufacture products according to recognised standards can have their product marked with widely recognised Standards Australia five ticks Certified Product logo (Plate 1). Plate 1. Certified Product logo demonstrating compliance to a recognised product standard. Definitions Quality Assurance A planned and systematic pattern of all actions necessary to provide adequate confidence that the product optimally fulfils customers expectations. Quality Management System (QMS) A set of procedures an organisation establishes to guarantee it products will satisfy consumers. Applying for QMS and/or product certification A good starting point for gaining information on applying for QMS certification and/or certification for a product to an Australian Standard is Quality Assurance Services Pty Ltd, contactable on the internet at

16 Notes: Important references AS/NZS ISO 9000 (2000). Quality Management Systems Fundamentals and Vocabulary. Standards Australia, Homebush, NSW. QAS (2000). Understanding the AS/NZS ISO 9000:2000 Standards. Training manual produced by Quality Assurances Services, New South Wales. Acknowledgement The authors would like to extend a special thankyou to members of the peer review committee for critically evaluating this document: Dr Trevor Gibson, NSW Agriculture; Dr Kevin Wilkinson, Agriculture Victoria; Mr Darren Bragg, Resource NSW; Mr Garry Kimble, Quality Assurance Services; Dr Martin Line, University of Tasmania; Mr Chris Rochfort, EC Sustainable Environment Consultants and Dr Pam Pittaway, University of Southern Queensland. Recycled Organics Unit 2003 Produced by: Recycled Organics Unit PO Box 6267 The University of New South Wales Sydney Australia 1466 Online contact details: ROU Internet Angus Campbell Whilst all care is taken in the preparation of this Information Sheet, the information provided is essentially general in nature and the Recycled Organics Unit disclaims all liability for any error, loss or other consequence which may arise from application of the information in any specific situation

17 Information Sheet No. 3-3 On-site Field Testing and Monitoring for Quality 1 Information Sheet No. 3-3 Third Edition 2007 Inside This Sheet Why is on-site field testing and monitoring important? Easy-to-do field tests 2 Definitions Field testing safety tips 3 Sampling 5 Temperature 6 7 ph 8 Maturity 10 Moisture content Oxygen status 11 Important references & acknowledgement Recycled Organics Unit 2003 ISBN Why is on-site field testing and monitoring important? On-site field testing procedures are employed at a composting facility to maintain process control and to generate products of consistent quality. Testing and monitoring is a core component of a Quality Management System (QMS), required to ensure that the systems in an organisation are performing effectively. Process control is defined as the stringent and documented monitoring of all critical control points in a composting operation so as to minimise defects and make products which can be guaranteed to customers (Recycled Organics Unit, 2002). Products that vary in quality over time may result in customer dissatisfaction and loss of business. This can occur when manufacturing systems are not regularly checked and when products are not tested against pre-determined quality criteria. To avoid releasing non-conforming products containing recycled organics into the market place that is, product which does not conform to specification testing and monitoring procedures need to be employed at all stages of production. There are two categories of testing that can be performed on-site. Rapid, on-site testing can be done in the field (e.g. at the composting pile) with lightweight and portable scientific equipment. Field tests can be performed quickly, allowing the immediate identification of problems. This allows problems to be quickly rectified, thus minimising impacts on final product quality. The second type of on-site testing possible at a composting facility is laboratory testing. This involves the analysis of samples in a dedicated room, usually with non-portable and more accurate equipment than that employed for field testing. On-site laboratory tests that can be used to maintain process control and product quality at a composting facility are discussed in Information Sheet No This Information Sheet reviews easy, inexpensive field tests that can be used to from the basis of a testing program at a composting facility. Easy-to-do field tests Field testing should be performed at all stages of the production cycle, though the stages will vary depending on types of feedstocks processed, how they are managed onsite, and what type of products are manufactured. Please note that tests described in this Information Sheet are targeted towards composting operations. Tests performed in the field can also play an important role in environmental management. For example, monitoring of oxygen content within a turned pile can indicate when odour formation is likely to occur. Interventions, such as aeration or turning may be needed so that anaerobic or low oxygen conditions do not form, thereby minimising the potential for odour Information for organic resource recovery, management, research & development, quality systems and training

18 production and impacts on air quality. Tests used do not necessarily have to conform to those outlined in an Australian Standard or other relevant standard. What is important is that tests are employed regularly and consistently to maintain product quality, most effectively achieved through the application of a well documented QMS. It is important to note that not all tests can be done in the field or in an on-site laboratory. When a new type of feedstock is accepted at a composting facility, for example, nutrient content may have to be analysed by an off-site laboratory to allow a compost recipe to be formulated. Field tests described here are quick and easy to perform. Tests are described for: Definitions Process Control Stringent and documented monitoring of all critical control points in a composting operation so as to minimise defects and make products which can be guaranteed to customers. Quality Management System (QMS) Is a set of procedures an organisation establishes to guarantee it products will satisfy consumers. Feedstock Organic materials used for composting or related biological treatment systems. Different feedstocks have different nutrient concentrations, moisture, structure and contamination levels (physical, chemical and biological). Turned Pile System of composting involving the periodic turning of piles of organic matter with mechanical equipment (e.g. front-end loaders or specialised windrow turners) between 1.5 and 3 m in height. Turning assists in: aeration and oxygen re-supply; eliminating odours; reducing consolidation, and moisture and nutrient re-distribution. Pasteurisation The process whereby organic materials are treated to kill plant and animal pathogens and weed propagules. In-vessel System of composting involving the use of an enclosed chamber or vessel in which (in most cases) the composting process is controlled by regulating the rate of mechanical aeration. Aeration assists in heat removal, temperature control and oxygenation of the mass. Aeration is provided to the chamber by a blower fan which can work in a positive (blowing) and/or negative (sucking) mode. Rate of aeration can be controlled with temperature, oxygen or carbon dioxide feedback signals. temperature; moisture content; ph; maturity; and oxygen status. Suppliers and approximate prices for scientific equipment recommended for each of these field tests is shown in Figure 1. Figure 1. Equipment suppliers and approximate prices Temperature meters ph kits Bimetal windrow thermometer: analogue type, stem length 91 to 183 cm, stainless steel probe, crystal face, hermetically sealed. REOTEMP Instrument Corporation, USA. Cost $223 to $554. Digital hand held composting thermometer: water resistant digital meter, LCD display, 91 to 183 cm stainless steel compost probe. REOTEMP Instrument Corporation HI9063, USA. Cost from $944, depending on probe length (see Plate 4). ph test kit: pocket sized with enough tablets to perform 50 tests, and calibration chart, ph range 4-8. Palintest SL150, available from Crown Scientific, NSW. Cost $115 (see Plate 11). Maturity kits Compost maturity test kit: measures carbon dioxide and ammonia concentrations based on gel colorimetric analysis. Kit for 6 analyses, manufactured by Solvita, available through Biotec Pacific, Victoria. Cost $198 (see Plate 15). Oxygen meters Combined oxygen and temperature meter: portable, stainless steel probe, 9V battery, galvanic cell type oxygen detector, LCD display, resolution 1%, accuracy 1%. Manufactured by Demista, USA and available through Enviromulch Pty Ltd, VIC. Cost about $2376 (see Plate 20)

19 Field testing safety tips The field tests discussed here are not hazardous, but a few safety precautions need to be observed. Gloves: These should be worn at all times to prevent injury from sharp objects (e.g. glass and metal in contaminated feedstocks). Safety Glasses: Safety glasses or goggles need to be worn during all testing procedures. Ventilation: All testing areas, particularly enclosed rooms, need to be well ventilated. Equipment Precautions: Observe all safety precautions associated with equipment used for sampling and testing. edges, and outer surface, which are likely to have different qualities from the bulk of the material in the pile. A recommended sampling procedure for testing has been reported in AS 4419 (2002) for Soils for Landscaping and Garden Use. This method was developed for sampling a batch of product ready for sale, though it can be easily adapted for use as in-process sampling method. The method shown below is appropriate for field testing procedures that require a sample of material for analysis. 1. From each batch of material (e.g. a windrow, pile or from a vessel) to be tested, collect 20 random samples at various depths, each having a volume of not less than 1 L (Plate 1). 2. Blend these samples to prepare a composite sample of not less than 20 L (Plate 2). 3. A sub-sample should be taken which is convenient to work with and suited to the testing equipment and containers. Sub- Plate 1. Random sampling of finished compost from 20 different points in the pile. Hygiene: If any materials are handled including raw feedstocks and compost during field testing procedures, hands should always be washed with soap and hot water afterwards. Sampling The first step in testing is to obtain a representative sample, or to sample from representative locations. The sample (or sampling points) should reflect the overall characteristics of the material being tested. Plate 2. Blending of random samples to form a 20 L sample of homogenous, finished compost representative of the bulk material. Testing performed on a sample that is not representative of the bulk material will produce unreliable results. Collect a number of samples from different, representative locations in a pile and/or from several piles to ensure that a representative sample is obtained. Mix these samples together well and then draw sub-samples to be tested from the mixture. Avoid taking a disproportionate number of samples from the centre,

20 sampling can be done by the coning and quartering method. Form the combined sample into a conical shape on a clean surface; Plate 3. Sub-sampling of the combined sample by coning and quartering. The combined sample is formed into a cone, and divided into quarters. 4. Quarter and mix the sample in successive steps until the sample volume is reduce to a suitable size Plate 3). Usually 6-10 L of sample is required for a full range of tests. In the time that elapses between collecting and testing, it is possible for samples to lose moisture and undergo other changes. Therefore, samples should be collected shortly before testing. If samples must be collected some time in advance, they should be refrigerated (~2C) in a sealed plastic container or bag (NRAES, 1992). If samples are to be analysed by an off-site laboratory, seal the sample in a plastic bag and dispatch the same day of sampling. Note that if the sample is to be analysed for organic contaminants, a 1 L sample needs to be placed into a glass jar and sent to the laboratory as well. This is because the organic contaminants can react with plastic polymers in the bag. A convenient way of posting the packaged samples is in a polystyrene box

21 Temperature Temperature monitoring is an important component of a good process control system at a composting facility. The temperature of a composting system influences microbial growth and rates of decomposition. In composting systems that do not have automatic temperature control (e.g. through forced or induced aeration), maintenance of optimum temperatures (55-60C) are usually achieved through mechanical turning (Miller, 1993). Temperature monitoring can indicate: how well the process is performing poor feedstock recipes fail to heat up; when (or if) turning or aeration is required; and temperature readings and divide by the number of readings taken. This will be the average core windrow temperature. If all the mass present in a windrow, in-vessel or alternative system reaches temperature in excess of 55C for 3 consecutive days, effective pasteurisation of the material has occurred (Standards Australia AS 4454, 2002). A minimum of three turns (for turned pile systems) should be performed during this period to ensure the entire mass achieves a temperature above 55C. If material within the windrow or other system does not heat up, check moisture content (next section) and the recipe to ensure that adequate nitrogen was provided at the start of composting. If the compost temperature exceeds 60C, mechanical turning or some other form of aeration should be performed to remove excess heat. Plate 4. Digital hand held thermometer and stainless steel probe manufactured by REOTEMP, USA (see Figure 1 for details). when the material has been pasteurised meaning that weed propagules and pathogenic microorganisms have been destroyed by heat (55C for three consecutive days) (Standards Australia AS 4454, 2002). Materials Hand-held temperature meter with a probe at least 50 cm long. The device can be analogue or digital (Plate 4). Plate 5. Measurement and recording of temperature at the centre of a static pile. Method Temperature readings are taken in the hottest region of a system. In a windrow, that is the centre. To obtain an estimate of temperature in the core of a windrow, walk along the length and insert the probe, perhaps every few metres depending on windrow length (Plate 5). Note the ends of a windrow will be cooler, due to higher surface area available for heat loss. Sum the

22 Moisture content Moisture content is the portion of water of a material s total weight that is water. It is often expressed as a percentage. The non-water portion of a material is referred to as dry matter. Moisture content is an important variable when preparing feedstocks for composting. Optimum moisture content for composting is between 55 and 60% (Miller, 1993). if water is released, it is too wet (Plate 9). If the sample crumbles without further action when the fist is opened, the sample is too dry for composting (Plate 10). If the squeeze test indicates water is required to increase the moisture content of the material, it is suggested that moisture content be measured by the moisture content test reported in Information Sheet No Accurate moisture content measurements can be made in an onsite laboratory (Information Sheet No. 3-4), but this is difficult in the field. The method reported here is based on the squeeze test (Federal Compost Quality Assurance Organisation, 1994). This test provides a rough estimate of moisture content, but cannot be used to estimate the volume of water required to increase moisture content of a material. Neither can it be used to estimate the moisture content of a material with large particle sizes (>10 mm). The squeeze test just gives an indication as to whether a material may be too dry or too wet for composting. Plates 6 (left) and 7 (right). A small handful of sample is needed to do the squeeze-test for moisture (left). Squeezing of sample (right). Plates 8 (left) and 9 (right). Sample at a suitable moisture content for composting (left). The sample does not fall apart when the hand is opened, and breaks apart with light pressure. When the sample is at a correct moisture content for composting, no water is released between the fingers. Sample too wet for composting (right). Water is released between fingers. Materials ~1 L of fresh test sample. Method 1. Press a sub-sample into the flat of hand (Plate 6). 2. Close hand around the sample and squeeze firmly (Plate 7). Plate 10. Sample is too dry for composting as it crumbles once the fist is opened. 3. Open fist and evaluate structure of sample. If the sample is sufficiently moist for composting, it should crumble with light pressure (Plate 8). If the sample deforms, and does not fall apart when pressure is applied, or

23 ph Measurement of ph is an important process control strategy, particularly for compost recipe preparation and product formulation. ph is a measure of how acid or alkaline a material is. ph influences the availability of nutrients and plants vary in their tolerance to ph. New feedstocks processed at a facility should be tested for ph to determine whether they can be composted in their present condition. Such tests will establish whether amendments need to be added to adjust ph. The test described here uses a soil ph test kit. It is easy to use, reliable and results can be generated in about 2 to 3 minutes. Materials Colorimetric field ph test kit (see Figure 1 for details and Plate 11 for a picture of the Palintest Kit used). colour ph scale on the front of the reaction vessel (Plate 14). In general, organics most suited to composting have a ph between 6 and 8, and final products should have a ph which conforms to user requirements or a relevant product standard (e.g ). If feedstocks have a ph of less than 5, lime (calcium carbonate), hydrated lime (calcium hydroxide) or quicklime (calcium oxide) may need to be added to neutralise acidity present. If ph is greater than 9, an acidifying agent may need to be added to the material (e.g. elemental sulfur). Plates 11 (left) and 12 (right). Test kit used for testing ph (see Figure 1 for details) (left). This ph test kit comes with a reaction vessel which can analyse two samples at a time, and a surface printed colour chart for reading the ph value, colorimetric reaction tablets (in foil), a 2 ml sample scoop and a mixing spatula. Distilled water and bottle need to be purchased separately. All hardware stores stock distilled water and bottles (left). Add samples to the two test wells (right). It is a good idea to assess ph of the one bulk sample twice to ensure consistent results are obtained. Bottle of distilled water. Method 1. With the small scoop, transfer a 2 ml sample into each of the reaction wells. It is wise to duplicate the test just in case a non-representative sample is used (Plate 12). 2. Add distilled water until the 10 ml maximum fill line is reached. Cap the reaction vessel with the rubber stopper, shake, and add more distilled water if the 10 ml line is not reached (Plate 13). Plates 13 (left) and 14 (right). Add distilled water until the 10 ml line is reached (left). Determine the ph of the sample by comparing the colour of the solution to the standard colour chart printed on the face of the reaction vessel (right). 3. Add one reaction tablet per well. Shake the reaction vessel end-over-end for one minute. 4. Allow the solids to settle for a minute or two and compare the colour of the solution to the

24 Maturity Composts that are not fully decomposed, in some cases, can damage plants when incorporated into soil, or when applied in excess as a mulch. Immature products continue to undergo decomposition, resulting in oxygen consumption and temporary nutrient immobilisation in soil. To ensure that composted products are fully decomposed prior to sale, a maturity test should be performed on a batch. Such tests, however, are not appropriate for pasteurised products as they are sold as immature products. Pasteurised products have limited applications, being restricted for use largely as surface mulches. The test reported here is based on the Solvita Compost Maturity Test by Woods End Research Laboratory Inc., USA. The test is based on the use of gel-colorimetric analysis. It is a rapid test a result can be obtained in four hours if the sample is at an appropriate moisture content. Laboratory-based maturity tests involving the germination of seeds can take up to 5 days to generate a result. As a result, the Solvita Compost Maturity Test is being widely used in the USA as a rapid on-site maturity test. The test uses a gel that is sensitive to carbon dioxide gas evolved by immature composts. Maturity is determined by comparison against a standard colour chart. Materials One Solvita Compost Maturity test kit containing a gel stick, buffer pack and sample jar with a colour chart (see Plate 15 and Figure 1 for details). One 2 L plastic container. One paddle-pop stick. ~0.5 L fresh test sample. Method 1. Place 0.5 L of the sample into a 2 L plastic container and remove large particles (>10 mm) by hand. 2. Take a fist-full of the sample and squeeze tightly. The sample should wet the hand but not yield free water. Water should be added if too dry. If the sample is too wet, spread on paper towelling and let it dry out overnight at room temperature. 3. Empty one Solvita Buffer pack into the plastic container and blend well by stirring with a paddle pop stick (Plate 16). 4. Place some of the sample into the jar until the fill line is reached. Lightly tap on bench to consolidate sample. Top up with more sample if needed (Plate 17). 5. If the sample needed to be remoistened, let the jar stand with the lid placed loosely on the jar for hours. For samples not requiring re-moistening, proceed to step Open the Solvita Test foil packet (containing the gel stick) and be careful not to touch the contents. Do not allow the compost to touch the gel surface of the stick. Insert the pointed end of the gel stick into the sample so that it can be seen through the side of the jar. To do this, push the tip of the gel stick to the bottom of the jar. Do not use the gel stick if the gel is dried out or if the colour is not #8 on the chart (Plate 18). 7. Screw the lid tight and allow to stand at room temperature (20-25C) in the shade for four hours. Read the Solvita colour four hours after the test is started. To read the colour, observe the gel stick through the viewing side of the jar with the lid on. If condensation obscures the view, wipe it off with a tissue then replace lid. To assess sample maturity, compare gel colour to the colour chart (Plate 19). The test can be used to identify whether a batch of mature compost, or products containing mature compost are ready for sale. Note that some products may be immature, though they may qualify as a pasteurised product. Determination of whether a product is pasteurised is not possible with this test. In this case, temperature monitoring is required to prove that pasteurising temperatures were achieved for a sufficient period of time so that the product can be referred to as pasteurised. For this reason, the Solvita Compost Maturity Test should be used for products that are sold as mature composted products

25 Plates 15 (left) and 16 (right). The Solvita Compost Maturity test kit (left). Add buffer to the sample and mix thoroughly (right). Plates 17 (left), 18 (centre) and 19 (right). Place some of the sample into the jar until the fill line is reached (left). Insert the gel stick into the sample. Make sure the gel surface does not come into contact with the sample (centre). Determine maturity of sample by comparing it to the colour chart on side of jar after a period of 4 hours. In this case, the sample of compost can be considered to be immature, still requiring turning and aeration (right)

26 Oxygen status Oxygen (O 2 ) in a composting system has a marked affect on the rate of decomposition and odour formation. During the decomposition process, microorganisms consume oxygen present between the voids of composting particles. The rate of decomposition of organic materials is fastest when high levels of oxygen are present. Microorganisms require oxygen to oxidise or break down the organic fraction into simpler compounds. If low oxygen conditions develop, significant quantities of odour can be generated by microorganisms in the form of ammonia (NH 3, a pungent smelling odour), hydrogen sulfide (H 2 S, rotten egg smelling odour) and dimethyl disulfide (CH 3 SSCH 3, a foul smelling odour) (Miller and Macauley, 1988). Maintaining an aerobic (high O 2 ) composting environment is the key to minimising odours and maximising the rate of decomposition. Oxygen monitoring can be useful when potentially odorous feedstocks are processed (e.g. food organics) in turned piles or in-vessel composting systems. Oxygen monitoring with a galvanic cell type portable meter can determine when turning or aeration is required. Method 1. Turn the meter on and check battery status. Depending on the type of meter, a warm up period of up to 5 minutes may be required. 2. If needed, calibrate instrument by aspirating the cell (squeezing and releasing the rubber bulb to draw fresh air into the unit). Check display to make sure it is reading 21% (most meters round the result to the nearest whole number). Adjust calibration screw if required. 3. Walk along the length of the windrow (or similar composting system) and insert probe, perhaps every few meters depending on length or size of windrow. The probe should be inserted into the centre of the composting mass where O 2 deficiencies are more common (Plate 21). 4. Aspirate bulb on the meter four to six times until the reading becomes steady (Plate 21). 5. Record reading. 6. Note the ends of a windrow will have a higher O 2 concentration, due to higher surface area available for gas exchange. Sum the O 2 readings and divide by the number of readings taken. This will be the average O 2 concentration. Oxygen concentration should preferably be greater than 10% for optimising process efficiency. Facility managers can specify a threshold concentration that triggers the timing of aeration. It is suggested here that if the concentration of O 2 is less than 12% in an actively composting mass, it is time to schedule turning or otherwise aerating the composting mass to prevent odour formation and to maximise the rate of decomposition. Plates 20 (left) and 21 (right). A combined O 2 and temperature meter with a stainless steel probe manufactured by Demista (left). Sampling of gas in the centre of a static pile (right). The bulb is being aspirated to withdraw air from the compost pile into the O 2 sensor located in the meter. To minimise odour generation and to maximise rate of composting, the concentration of O 2 (on a volumetric basis) should be kept above 12% (Standards Australia AS 4454, 2002). In normal outdoor air, the concentration of O 2 is ~20.9%. Materials One portable O 2 meter with a probe at least 50 cm long (see Plate 20 and Figure 1 for outlets)

27 Notes: Important references Federal Compost Quality Assurance Organisation (1994). Methods Book for the Analysis of Compost. BGK NR 230, Bundasgutegemelnschaft Kompost e.v., Germany. Miller, F.C. and B.J. Macauley (1988). Odours arising from mushroom composting: a review. Australian Journal of Experimental Agriculture 28: Miller, F.C. (1993). Composting as a process based on the control of ecologically selective factors. In: Soil Microbial Ecology: Applications in Agricultural and Environmental Management. F. Blaine Metting Jr (Ed.). New York, USA. Marcel Dekker Publishing. pp Natural Resource, Agriculture, and Engineering Service (1992). On-Farm Composting Handbook. Rynk, R. (Ed.). NRAES Publication No. 54, Cooperative Extension, Ithaca, New York, USA. Recycled Organics Unit (2002). Guide to Developing a Process Control System for a Composting Facility. Second Edition. Recycled Organics Unit, internet publication: Standards Australia (2002). AS 4419 Soils for landscaping and garden use. Standards Australia, Homebush, NSW. Standards Australia (2002). AS 4454 Composts, soil conditioners and mulches. Standards Australia, Homebush, NSW. Acknowledgement The author would like to extend a special thankyou to members of the peer review committee for critically evaluating this document: Dr Trevor Gibson, NSW Agriculture; Dr Kevin Wilkinson, Agriculture Victoria; Mr Darren Bragg, Resource NSW; Mr Garry Kimble, Quality Assurance Services; Dr Martin Line, University of Tasmania; Mr Chris Rochfort, EC Sustainable Environment Consultants and Dr Pam Pittaway, University of Southern Queensland. Produced by: Recycled Organics Unit PO Box 6267 The University of New South Wales UNSW Sydney 2052 Contact Internet Angus Campbell Whilst all care is taken in the preparation of this Information Sheet, the information provided is essentially general in nature and the Recycled Organics Unit disclaims all liability for any error, loss or other consequence which may arise from application of the information in any specific situation. Recycled Organics Unit

28 Information Sheet No. 3-4 On-site Laboratory Testing for Quality 1 Information Sheet No. 3-4 Third Edition 2007 Inside This Sheet Advantages of on-site laboratory testing Setting up an on-site laboratory 2 Sampling Testing safety tips Test 1: Moisture content 4 Definitions Test 2: Physical contamination Test 3: ph Test 4: Electrical conductivity Test 5: Particle size grading Important references Acknowledgement Advantages of on-site laboratory testing On-site testing and monitoring is the key to maintaining good process control at a composting site. Regular testing and monitoring ensures that product quality is maintained and problems that arise are quickly identified and resolved in a short period of time. Furthermore, testing and monitoring are integral components of a quality management system. These systems are based on a set of procedures an organisation uses to manufacture products of consistent quality (see Information Sheet No. 3-1). Information Sheet No. 3-3 reviewed five field tests that can be easily performed at a composting site to achieve good process control. Some simple tests, however, cannot be performed in the field. A small room or laboratory at a composting facility may be appropriate so more detailed tests can be done. This information sheet reviews laboratory tests that can be done at relatively low cost at a composting facility. Some equipment specified can be obtained from around the home. Some specialised equipment, however, needs to be purchased, but it should be remembered that a basic laboratory does not need to be expensive. Tests reviewed in this Information Sheet include: moisture content; visible contamination; ph; electrical conductivity; and particle size grading. Plate 1. Photograph of an on-site laboratory at a composting facility. This laboratory is primarily used for testing the quality of products manufactured before they are sold. Results produced by the laboratory complement those performed by an independent off-site laboratory (see Information Sheet No. 3-5). Recycled Organics Unit 2003 ISBN Information for organic resource recovery, management, research & development, quality systems and training

29 Setting up an on-site laboratory An on-site laboratory is an extremely useful addition to a composting facility. An on-site laboratory allows a composting facility to perform simple tests at low cost that may otherwise need to be done by an offsite commercial laboratory. Apart from significant cost savings, an on-site laboratory can process samples and generate test results in a short period of time. This is particularly important if immediate decisions regarding feedstock receival, processing or product formulation need to be made. Testing and monitoring at all stages in a composting facility gives the operator much more control and confidence regarding the operation and management of a composting operation. It should be remembered that final product testing needs to be performed by an independent off-site laboratory. This is particularly so when a manufacturer produces product under a product certification system in this instance, independent verification of product quality is mandatory. Furthermore, independent off-site product testing for quality gives customers a greater level of confidence in product offered for sale (see Information Sheet No. 3-5). Tests described here, however, can be considered to be in-process tests. The tests are not hazardous, so no special laboratory design is necessary. Ideally, the room designated as an on-site compost laboratory should have windows for ventilation, with good lighting and adequate benches for conducting tests and storing equipment and samples. The laboratory should either be a secure space with restricted access, or have materials and equipment stored in a secure lockup cabinet to prevent misuse and/or damage from unauthorised personnel. The room should be kept around 20C, but this is dependent on resources available for an air conditioning system. Shelving up to eye-level on the walls is convenient for storing equipment and consumables. A sink with running water is also needed to wash containers and glassware. All on-site laboratories should contain a complete and up-to-date Work Cover approved first aid kit and fire extinguisher/blanket for any emergencies that may arise. A 20 L plastic bucket should be kept in the room to dispose of sample waste. In addition, tissues and paper towelling should be kept in a convenient place to clean tips of electrodes and to contain liquid spills. Safety precautions, of course, should be observed for all equipment used in the laboratory. Other safety precautions that need to be observed in a laboratory regarding the use of gloves, safety glasses and hygiene are reviewed in the box to the right. Sampling The first step in testing is to obtain a representative sample, or to sample from a representative location. Recommended sampling strategies can be seen in Information Sheet No. 3-3, and further described in Information Sheet No Testing safety tips The tests discussed here are not hazardous, but a few safety precautions need to be observed. Gloves These should be worn when hot containers or sharp objects are handled (e.g. glass during visible contamination assessments). Safety glasses Safety glasses or goggles need to be worn during all testing procedures. Ventilation All testing areas, particularly enclosed rooms, need to be well ventilated. Equipment precautions Observe all safety precautions associated with equipment used for sampling and testing. Hygiene If any materials are handled, including raw feedstocks and compost during field testing procedures, hands should always be washed with soap and water afterwards. First aid kit A Work Cover approved first aid kit should always be conveniently located in the work place. Fire extinguisher A Work Cover approved fire extinguisher and fire blanket should always be conveniently located in the work place. Test 1: Moisture content Moisture content is the portion of a material s total weight that is water. It is often expressed as a percentage. The non-water portion of a material is referred to as dry matter. Moisture content is an important variable when preparing feedstocks for composting. Optimum moisture content for composting is between 55 and 60% (Miller, 1993)

30 Field tests, such as the fist test (see Information Sheet No. 3-3) can be used to estimate moisture content such as whether a recipe is adequate, too dry or too wet for composting. The fist test, however, cannot be used to accurately determine how much water is required to increase the moisture content of a compost recipe, windrow or material contained within any other system. To do this, a more accurate estimate of moisture content is required. The test described here is based on the use of an oven or microwave to assist with drying so that moisture content can be quickly determined. Materials: Microwave oven (~600W), if samples do not contain pieces of metal or plastic; or a drying oven (operating at ~105C) (Plate 2). One balance (max 6 kg, accurate to 1 g). Microwave proof plastic dish, preferably 25 cm in diameter and 5 cm in height (if a microwave is used for drying); or a metal dish (if an oven is used for drying). All containers need to be clean and dry. 0.5 L of fresh test sample. 1 metal spoon. Method: 1. Determine mass (g) of a dish (m 1 ) that is large enough to hold 0.5 L of material (Plate 3). 2. Place the 0.5 L sample in the dish and determine combined mass (g) of dish and product (m 2 ). 3a. Microwave drying method: Place the dish of moist material in a microwave initially on full power for 5 minutes. Remove and record weight. Reheat sample in 5 minute intervals until a constant weight is obtained. Check that charring or burning does not occur (if so, restart method). Determine mass (g) of dish plus dried product (m 3 ). 3b. Oven drying method: Place the dish of moist material in the oven set at 105C. Leave it there until its mass is constant (~24 hours). Determine mass of the dish plus dried product (m 3 ). Calculation: A procedure for adjusting the moisture content of material within a composting system can be found in Recycled Organics Unit (2002). Figure 1. Specialised equipment suppliers and approximate prices Balances Ohaus CT 6000 portable laboratory balance, 6000 g maximum capacity, accurate to 0.5 g. Digital LCD display and tare function. Crown Scientific, NSW. Cost $ (see Plate 2). BSE digital platform scale, 60 kg maximum capacity, accurate to 50 g. Digital LCD display and tare function. Wedderburn, NSW. Cost $ (see Plate 4). Bottles, measuring cylinders, funnels and filter papers Shaking bottle, 250 ml capacity, wide mouth, plastic. Crown Scientific, NSW. Cost $3.70 (see Plate 8). Measuring cylinder, 250 ml capacity, plastic, printed graduations. Crown Scientific, NSW. Cost $30.15 (see Plate 8). Filter funnel, plastic, unbreakable, 120 mm top diameter. Crown Scientific, NSW. Cost $3.02 (see Plate 8). Filter papers, Whatman No. 1, pack of 100. Crown Scientific, NSW. Cost $48.66 (see Plate 8). Sieves Endecotts 450 mm diameter, 16 mm aperture plated steel sieve. High sides (300 mm). Crown Scientific, NSW. Cost $ (see Plate 4). ph and electrical conductivity meters Agritest combined ph and electrical conductivity meter kit. Comes with carry case and calibration solutions. Crown Scientific, NSW. Cost $ (see Plate 8)

31 Plate 2. Equipment for determining moisture content. A laboratory drying oven (not included in the equipment package, though this particular drying oven Heraeus Series 7000 function line is available from Radiometer) (left), balance (centre) and metal spoon and weighing dishes (right). Please note that the metals drying dishes (baking trays) are available from any good hardware store. Definitions Process Control Stringent and documented monitoring of all critical control points in a composting operation so as to minimise defects and make products which can be guaranteed to customers. Quality Management System Is a set of procedures an organisation establishes to guarantee it products will satisfy consumers. Moisture Content The fraction or percentage of a substrate comprised of water. Moisture content equals the weight of the water portion divided by the total weight (water plus dry matter portion). ph A measure of the concentration of hydrogen ions in a solution. ph is expressed as a negative exponent. Material that has a ph of 8 has ten times fewer hydrogen ions than a material with a ph of 7. The lower the ph, the more hydrogen ions are present, and the more acidic the material is. The higher the ph, the fewer hydrogen ions present, and the more basic it is. A ph of 7 is considered neutral. Plate 3. Procedure for determining the moisture content of a sample. Taking the mass of a clean and dry metal weighing dish (far left), taking the mass of a fresh sample of compost before placement in the oven (left), placing the dish and sample into the drying oven for ~24 hours (right), and recording the mass of the dry sample and weighing dish (far right). Electrical conductivity A measure of a solution s ability to carry an electrical current; varies both with the number and type of ions contained in the solution. Usually measured in deci-siemens per metre (ds m -1 )

32 Test 2: Physical contamination Excessive contamination of feedstocks received with glass, metal, plastic, stones and clods of clay is the most common cause of variable product quality. Analysis of contamination is a key step in being able to accept or reject a batch of material. It is difficult to perform a comprehensive assessment of contamination at the gate, except for visually inspecting for large contaminant items, such as plastic bags, glass bottles, carpet etc. The methods reported here are for determining the visible contamination of the final product, whether it be a mulch, soil conditioner, potting mix, soil etc. Standards Australia (2003) details a physical contamination procedure in AS 4454 for Composts, Soil Conditioners and Mulches (Appendix H). Two simpler procedures are mentioned here to enable operators to determine the contamination level of final products in a short period of time. The method reported here measures physical contamination on a mass basis. A limitation of this method is that products contaminated with significant quantities of very low density plastic, such as that from shopping bags, will show very low levels of contamination. One sieve with apertures of 16 mm. Metal spoon or tweezers. Plastic sheeting. One large digital platform scale (max ~60 kg, accurate to 50 g). One small balance (max 6 kg, accurate to 1 g). ~25 L of fresh test sample. Method 1. Weigh the empty plastic bucket on the large platform scale. Record mass in kg (m 1 ) (Plate 5). 2. Weigh the ice-cream container on the small balance. Record mass in kg (m 2 ). 3. Fill the plastic bucket with the test sample. Weigh the entire bucket and contents on the large platform scale. Record mass in kg (m 3 ). 4. With the 16 mm sieve, screen out the small-sized fraction onto plastic sheeting. With a spoon or tweezers, remove all visible contaminants (e.g. glass, metal, plastic, stones and clods of clay) and place them in the ice-cream container. Dispose of uncontaminated material (Plate 6). 5. Contaminants >16 mm in size can be removed by hand (with gloves if sharp object are present). Place the contaminants in the ice-cream container as before. 6. Record mass of the ice-cream container and contaminants in kg (m 4 ) on the small balance. If it weighs more than 6 kg, use the large platform scale. Calculation: % Physical Contamination (by mass) m4 m 100% Acceptable levels of physical contamination in final products depends on the composting facility, contracts for receival and customer requirements. Excess contamination is often removed by screening prior to sale of the product. A guide to acceptable contamination levels in composts, soil conditioners and mulches is given by Standards Australia (AS 4454, 2003) in Table 3.1. Plate 4. Equipment for determining the physical contamination of a final product. 3 m m 2 1 In most cases, however, this rarely occurs because feedstocks with such high levels of physical contamination are rejected at the gate. Materials: One 20 L bucket (Plate 4). One two litre ice-cream container

33 Plate 5. Taking the mass of a 20 L bucket on the platform scale (left) and filling the bucket with a representative sample of product for visible contamination assessment (centre). The mass of the bucket and product is taken (right). Plate 6. Screening of the sample through a 16 mm sieve onto plastic sheeting (left) and removal of contaminants with a metal spoon from the sieved fraction (centre). The contaminants are placed into an ice-cream container of known mass (right). Plate 7. Removal of large contaminants from the material remaining on the sieve (left) and measurement of the total mass of contaminants in the sample (right)

34 Test 3: ph ph is a measure of how acid or alkaline a material is. ph influences the availability of nutrients and plants vary in their tolerance to ph. Measurement of ph is an important process control strategy, particularly for compost recipe preparation and product formulation. New feedstocks processed at a facility should be tested for ph to determine whether they can be composted in their present condition. Such tests will establish whether amendments need to be added to adjust ph. A colorimetric field test procedure for measuring ph is reviewed in Information Sheet No The procedure used here provides more accurate results using a combined ph and electrical conductivity meter. Materials: One 2 L ice cream container (no lid required) (Plate 8). One 250 ml plastic bottle with screw type lid. One 250 ml plastic measuring cylinder. 2. Moisten sample with distilled or deionised water until water can just be squeezed from it with your hand (Plate 9). 3. Mix sample with a metal spoon and ensure all of sample is moist. 4. Place 100 ml of the sample into the 250 ml plastic bottle. Drop from a height of 5 cm five times to consolidate the sample. Top up with more sample to reach 100 ml if required. 5. Add deionised or distilled water with the measuring cylinder until the 250 ml mark is reached, indicated on the side of the bottle (Plate 10). 6. Seal the bottle and shake by hand for a few seconds. Repeat 4 more times at 20 minute intervals. 7. Fold a filter paper into the fan style and insert into funnel. Put end of funnel into a plastic disposable cup (Plate 11). 8. Slowly pour off the liquid (from the 250 ml bottle in step 6). 9. Turn on the ph meter and calibrate if necessary (see manufacturer s instructions). 10. Insert ph probe into the extract and record reading once it has stabilised. In general, organics most suited to composting have a ph between 6 and 8, and final products should have a ph that conforms to user requirements or a relevant product standard (e.g ). If feedstocks have a ph of less than 5, lime (calcium carbonate), hydrated lime (calcium hydroxide) or quicklime (calcium oxide) may need to be added to neutralise acidity present. If ph is greater than 9, an acidifying agent may need to be added to the material (e.g. elemental sulfur). distilled or deionised water. Combined ph and electrical conductivity meter, accurate to 0.2 ph units. One clean disposable drinking cup; One Whatman No. 41 filter. One plastic funnel. One metal spoon. 1 L of fresh test sample. Plate 8. Equipment for determining the ph of a sample of material. Method: 1. Place about 1 L of fresh sample into the 2 L ice cream container

35 Plate 9. Moistening the sample of material to field capacity (left), and placing a 100 ml portion of the sample into a 250 ml graduated shaking bottle (right). Plate 10. Addition of distilled water into the bottle (left), and shaking of the bottle by hand (right). Plate 11. Filtering the suspension through a filter placed in a funnel (left) and insertion of the combined ph and electrical conductivity meter into the filtered extract (right). Note that not all of the liquid in the bottle needs to be filtered before the ph test can be done. Just enough liquid to cover the tip of the ph electrode in the cup is required (~2 cm deep)

36 Test 4: Electrical conductivity Measurement of electrical conductivity is an important process control strategy for the same reasons as outlined above. Electrical conductivity is a measure of how salty a material is. Composts high in salts can kill plants by causing water stress and ion toxicities. The amount of soluble salts in a material can be determined with a conductivity meter which passes a small electric current between two electrodes. Electrical conductivity increases as the concentration of soluble salts increases. The electrical conductivity method reported here is based on Appendix A of Standards Australia AS 4454 (2003). New feedstocks used at a facility should be tested for electrical conductivity to determine whether they can be composted and formulated into quality products. Such a test may indicate that highly saline feedstocks cannot be composted as they will raise the electrical conductivity of the final product to an unacceptable level. One 250 ml plastic measuring cylinder. distilled or deionised water. Combined ph and electrical conductivity meter accurate to 0.05 ds/m. One clean disposable drinking cup; One Whatman No. 41 filter. One plastic funnel. One metal spoon. 1 L of fresh test sample. Method 1. The same filtrate (solution) produced by the ph test can be used for this test. If the ph test had not been done, please follow steps 1 through to 8 of the ph test. 2. Turn on the combined ph and electrical conductivity meter and calibrate if necessary (see manufacturer s instructions). 3. Insert electrical conductivity probe into the filtered extract and record reading once it has stabilised. The reading should be recorded in ds/m (Plate 12). Note that some electrical conductivity meters read in ms (actually, ms/cm). Because one ms/cm equals one ds/m, readings in ms/cm can be written as ds/m without any conversion. Incoming feedstocks with an electrical conductivity in excess of 2 ds/m need to be noted as they produce quite saline composts. Such products need be applied in restricted amounts to soils, as plants differ in their sensitivity to salinity. Standards Australia (AS 4454, 2003) in Section 2 outlines the labelling requirements for different products containing recycled organics for electrical conductivity. Processing of saline feedstocks will depend on the quality of composts produced, and customer requirements. Saline composts can be blended with other less saline products, thereby diluting the salt content and reducing the electrical conductivity of the final products. This can be done during the product formulation stage of composting. Alternatively, saline feedstocks can be blended with less saline feedstocks to reduce the overall electrical conductivity. Plate 12. Measurement of electrical conductivity in the same filtered extract prepared in the ph method. The maximum electrical conductivity of a feedstock accepted at the gate will depend on the nature of products generated by the facility and customer requirements. Materials: One 2 L ice cream container (no lid required). One 250 ml plastic bottle with screw type lid

37 Test 5: Particle size grading Particle size grading is an important aspect of product formulation. Coarse particles in products designated as soil conditioners, fine mulches, potting mixes or soils for example, may be unacceptable to consumers. Particle size grading can indicate the efficiency of the screening system in place. The method reported here is based on Appendix F in Standards Australia AS 4454 (2003). The method uses a metal sieve to separate particles based on size. Materials: One sieve with apertures of 16 mm (Plate 13). Calculation: Particles with a diameter > 16 mm (% of product) The product complies with the particle size grading requirement, for a: = m 3 - m 2 m 2 - m 1 Soil conditioner if not more than 20% is retained on the sieve; Fine mulch if more than 20% but less than 70% is retained on the sieve; and Mulch if equal to or more Plate 13. Equipment needed for the particle size grading test. than 70% is retained on the sieve (AS 4454, 2003). One small balance (max 6 kg, accurate to 1 g). Metal drying dish. Plastic sheeting. 1 L of test sample. Method 1. Record the mass (g) of the clean and dry metal drying dish on the small balance (m 1 ). 2. Select a representative sample of product (1 L) and spread out on the metal dish and allow to air dry for at least 5 days if wet. Plate 14. Sieving of the sample through the 16 mm sieve (left) and weighing of the sieved fraction on the small balance (right). 3. Record mass (g) of dish with the air dried sample on the small balance (m 2 ). 4. Place the sample on the 16 mm sieve and shake in +a horizontal plane for 1 minute over plastic sheeting (Plate 14). 5. Empty the particles retained in the sieve back into the metal dish and record its mass (g) on the small balance (m 3 )

38 Notes: Important references Miller, F.C. (1993). Composting as a process based on the control of ecologically selective factors. In: Soil Microbial Ecology: Applications in Agricultural and Environmental Management. F. Blaine Metting Jr (Ed.). New York, USA. Marcel Dekker Publishing. pp Recycled Organics Unit (2002). Guide to Developing a Process Control System for a Composting Facility. Second Edition. Recycled Organics Unit, internet publication: Standards Australia (2003). AS 4454 Composts, soil conditioners and mulches. Standards Australia, Homebush, NSW. Acknowledgement The authors would like to extend a special thankyou to members of the peer review committee for critically evaluating this document: Dr Trevor Gibson, NSW Agriculture; Dr Kevin Wilkinson, Agriculture Victoria; Mr Darren Bragg, Resource NSW; Mr Garry Kimble, Quality Assurance Services; Dr Martin Line, University of Tasmania; Mr Chris Rochfort, EC Sustainable Environment Consultants and Dr Pam Pittaway, University of Southern Queensland. Produced by: Recycled Organics Unit PO Box 6267 The University of New South Wales Sydney Australia 1466 Online contact details: ROU Internet Angus Campbell Whilst all care is taken in the preparation of this Information Sheet, the information provided is essentially general in nature and the Recycled Organics Unit disclaims all liability for any error, loss or other consequence which may arise from application of the information in any specific situation. Recycled Organics Unit 2003

39 Information Sheet No. 3-5 Third Edition 2007 Inside This Sheet 1 When is commercial laboratory testing necessary? Recommended commercial laboratory tests for quality Definitions Sampling and sample preparation How to select a laboratory How to interpret a laboratory report Case studies Important references Acknowledgement Information Sheet No. 3-5 Commercial Laboratory Testing for Quality Recommended tests and how to select an independent laboratory When is commercial laboratory testing necessary? Periodic commercial laboratory testing by an independent laboratory is necessary to ensure that products manufactured conform to customer requirements or pre-designed specifications. Commercial laboratory (off-site) testing complements field and on-site testing performed at a composting facility to achieve good process control (see Information Sheet Nos. 3-3 and 3-4). Testing by an off-site laboratory (e.g. Plate 1) provides manufacturers and customers with assurance that products generated are of a certain quality. On-site testing, such as that performed in the field and in an onsite laboratory are critical components of a good process control system at a composting facility. Process control is defined as the stringent and documented monitoring of all critical control points in a composting operation so as to minimise defects and make products which can be guaranteed to customers (Recycled Organics Unit, 2002). Testing done on-site, particularly on final products, however, should be verified by an independent off-site laboratory. Self-declaration of product quality may not be sufficient to provide consumers with purchasing confidence. This is particularly true for products suited to emerging agricultural markets. Commercial laboratory testing of products manufactured is required if product certification under an Australian Standard is sought (see Information Sheet No. 3-2). Plate 1. Photograph of a commercial off-site environmental laboratory, capable of testing composts, soil conditioners, mulches, potting mixes and soils. Recycled Organics Unit 2003 ISBN Information for organic resource recovery, management, research & development, quality systems and training

40 Periodic off-site testing is necessary if the composting facility is to apply for quality management system certification (see Information Sheet No. 3-2). Quality system certification is a consumers guarantee of the manufacturer s commitment to quality. In some cases, off-site testing may be done periodically if a purchaser requires a batch of product to meet a given standard. Production of quality compost is necessary not only to build a large client base, but also to expand the market for, and profitability of manufacturing compost and products containing recycled organics. Please note that sample handling and management guidelines for consistent analysis of product quality for use by laboratories are provided in Information Sheet No Recommended off-site tests for quality Off-site testing is often performed on new feedstocks that are considered being processed on-site, and on the final products manufactured. Tests on feedstocks that have not been previously processed on-site is necessary to determine whether the material is of sufficient quality so as to not affect the performance characteristics of final products manufactured. Tests performed will depend on the source of the feedstock and required characteristics and quality of products manufactured. For new feedstocks being considered for use, basic tests that should be performed include: total carbon; total nitrogen; ph; electrical conductivity; and chemical contamination (e.g. heavy metals and chlorinated hydrocarbons) Note that ph and electrical conductivity tests can easily be performed on-site. Methods are described in Information Sheet No Total carbon and total nitrogen Total carbon and total nitrogen are used to calculate the carbon to nitrogen ratio (g carbon per g nitrogen on a dry weight basis, or C:N ratio) of a feedstock. Determining the C:N ratio of a feedstock is important as this is a measure of the ability of microorganisms to initiate and complete the composting process. Woody garden organics, for example, have a high C:N ratio (e.g :1) meaning that they are high in carbon and low in nitrogen. Woody materials such as these are not easily degraded by microorganisms because they contain little nitrogen. Microorganisms need nitrogen so that they can make proteins and other substances to grow and divide. For this reason, woody garden organics (for example) may have to be blended with other feedstocks that have a low C:N ratio that is, materials high in nitrogen, such as food organics, manure or biosolids. The optimum C:N ratio for good composting is between 25 and 35:1, depending on the type of composting system employed (Standards Australia AS 4454, 2002). ph ph is a measure of how acid or alkaline a material is. ph influences Definitions Process Control Stringent and documented monitoring of all critical control points in a composting operation so as to minimise defects and make products which can be guaranteed to customers. Quality Management System A set of procedures an organisation establishes to guarantee it products will satisfy consumers. Feedstock Organic materials used for composting or related biological treatment systems. Different feedstocks have different nutrient concentrations, moisture, structure and contamination levels (physical, chemical and biological). C:N Ratio The ratio of the weight of organic carbon (C) to that of total nitrogen (N) in an organic material. Garden Organics Any garden derived organic (plant) materials generated by domestic, C&D and C&I sources. Garden organics is defined by its component materials including: putrescible garden organics (grass clippings); non-woody garden organics; woody garden organics; trees and limbs, and stumps and rootballs. Garden organics is one of the primary components of the compostable organics stream. ph A measure of the concentration of hydrogen ions in a solution. ph is expressed as a negative exponent. Material that has a ph of 8 has ten times fewer hydrogen ions than a material with a ph of 7. The lower the ph, the more hydrogen ions are present, and the more acidic the material is. The higher the ph, the fewer hydrogen ions present, and the more basic it is. A ph of 7 is considered neutral. Electrical Conductivity A measure of a solution s ability to carry an electrical current; varies both with the number and type of ions contained in the solution. Usually measured in deci-siemens per metre (ds m -1 )

41 the availability of nutrients and plants vary in their tolerance to ph. New feedstocks processed at a facility should be tested for ph to determine whether they can be composted in their present condition. Such tests will establish whether amendments need to be added to adjust ph. Most feedstocks processed at composting facilities tend to have a ph between 6 and 8. Electrical conductivity Electrical conductivity is a measure of how salty a material is. Composts high in salts can kill plants by causing water stress and specific ion toxicity. Electrical conductivity increases as the concentration of soluble salts increases. New feedstocks processed at a facility should be tested for electrical conductivity to determine whether they can be composted and formulated into quality products. Such a test may indicate that highly saline feedstocks (e.g. >2 ds/m) cannot be composted as they will raise the electrical conductivity of the final product to an unacceptable level. The maximum electrical conductivity of a feedstock accepted at the gate will depend on the nature of products manufactured by the facility and customer requirements. Chemical contamination Testing may be required to ensure feedstocks do not contain significant loadings of chemical or organic contaminants (e.g. heavy metals and chlorinated hydrocarbons) that are toxic to plants and animals (e.g. biosolids and some industriallyproduced organics). Standards Australia (AS 4454, 2002) states that all pasteurised and composted products should comply with the National Health Standards (ARMCANZ, 1995) or existing biosolids guidelines (e.g. NSW EPA, 1997), whichever is more stringent for chemical and organic contaminants. In NSW, the NSW EPA biosolids guidelines are more stringent than ARMCANZ (1995). A range of additional tests may be required on the final product(s) manufactured to confirm the quality of the material. Tests used will depend on the type of product manufactured and its intended use. Recommended tests for products containing recycled organics, such as composts, soil conditioners, mulches, potting mixes, soils for landscaping and garden use, and mulches used for playground surfacing can be found in the following Australian Standards and in the subsequent Information Sheets: AS/NZS 4422 (1996). Playground surfacing specifications, requirements and test method (Information Sheet No. 3-7); AS 4454 (2002). Composts, soil conditioners and mulches (Information Sheet No. 3-8); AS 3743 (2002). Potting mixes. (Information Sheet No. 3-9); AS 4419 (2002). Soils for landscaping and garden use (Information Sheet No. 3-10). Note that to demonstrate compliance with an Australian Standard under a product certification scheme, and/or in a registered quality management system, type testing and regular auditing is performed by an independent third party. Auditing is done to ensure that products conform to specifications and standards, and that a company s operations are consistently capable of producing quality products. Sampling and sample preparation Sampling procedures to follow for off-site laboratory testing will depend of the range of test(s) to be performed and the type of testing procedures. General batch and in-process sampling procedures for compost or related products can be viewed in Information Sheet No Advice on specific sampling requirements can be obtained from an off-site laboratory. In general, all samples should be put into a tough polythene bag, clearly labelled (e.g. type of sample, date of sampling and client name) on the outside with a waterproof marker; taped or tied securely, and despatched to the laboratory by postal bag or courier on the same day of sampling for testing. Further information is provided in Information Sheet No How to select a laboratory To obtain high quality service that is, prompt testing, results and interpretations that are consistently reliable an independent and quality assured laboratory should be used that has expertise in the area of testing required. As a minimum requirement, recognised laboratories with ISO 9000:2000 certification should be used for testing. Laboratories with ISO 9000:2000 certification have an audited and registered quality management system a customers guarantee the company has a commitment to quality

42 Laboratories that just have ISO 9000:2000 certification, however, do not undergo comprehensive technical evaluation, meaning that they may not be properly equipped to undertake certain testing procedures, although they do have a quality management system in place. Laboratories accredited by the National Association of Testing Authorities (NATA), however, are technically assessed for testing proficiency on a regular basis. Technical accreditation through NATA is the most definitive indication of a testing facility s specific technical competence. It identifies capability and proficiency in the relevant sampling and testing procedures, which are not identified or evaluated under ISO 9000:2000 certification. The logo is shown in Figure 1. Figure 1. NATA accredited laboratory logo. This type of accreditation system enables people who want a product, material or instrument to be checked or calibrated to find a reliable testing or calibration service able to meet their needs. Such accreditation also provides clients with confidence in results. The accreditation process involves a thorough evaluation of all the elements of a laboratory that contribute to the production of accurate and reliable data. These elements include staffing, staff qualifications, training, supervision, quality control, sample management, equipment, recording and reporting of test results and the environment in which the laboratory operates. Importantly, laboratory accreditation provides formal recognition to competent laboratories, thus providing a ready means for customers to access reliable testing and calibration services. When selecting a provider of laboratory services, consideration should be given to whether the laboratory is accredited to undertake the required tests. Tests used for a range of products should be based on those reported by Standards Australia. Use of standard testing methodologies is the key to gaining reliable and useful results that can help an operator maintain quality at a composting site. How to interpret a laboratory report Certified or accredited laboratories do not always provide written interpretation of testing performed on samples of material submitted for analysis. This is because they do not possess suitably qualified staff to offer such services. Interpretation services are very helpful because it is difficult for nonspecialists to determine the meaning of test results, and assess how they can be applied in the field to improve a process or the quality of a product manufactured. All laboratory services should report test results in standard units. Standard units of measurement are used when laboratories base their testing methodologies on particular Australian Standards. Confusion over the meaning of test results often occurs when laboratories do not use standard units for reporting. Laboratories that do not report test results in standard units (e.g. ms instead of ds/m when measuring the electrical conductivity of an organic product) should be avoided. When test results (based on an Australian Standard) are reported in standard units and in an appropriate format, the Australian Standard can be used to make further interpretations and sound recommendations for action. A relationship with a suitably certified or accredited laboratory is necessary for a composting operation to be quality orientated. Case studies Example of a poor laboratory report An example of a poor laboratory report is shown in Figure 2. Critical comments are noted in Figure 2. Example of a good laboratory report An example of a good laboratory report is shown in Figures 3 and 4. Critical comments are noted in both figures

43 Figure 2. Example of a poor laboratory report. Comments are noted in the call-out boxes. No job number specified possible indicating that no internal records are kept. What methods of testing were used? Laboratory Services #1 190 Thompson St Tel: (02) Savannah NSW 0000 Fax: (02) TEST REPORT: Nutrient assessment of compost Date sample received: 12/12/2002 Client: Mr John Citizen Quality Compost Products Pty. Ltd. 101 Thine Rd Timber NSW 0101 TEST UNIT RESULT ph ph units 7.4 Conductivity S 1555 Ammonium-N ppm 110 Ammonium-N + Nitrate N ppm 112 Total N % 0.71 Signed: Tony L James Consultant No quality system specified no guarantee of quality. No info regarding condition of sample received. No comparison to a standard and no interpretation provided. How many pages are in this report? Are there pages missing? Was the analysis checked by a second person? No internal quality control. No summary or recommendations provided. Non-standard units - S should be ds/m and ppm should be mg/l. Difficult to compare these results with a standard

44 Figure 3. Example of a good laboratory report. Note that page 2 of this example is shown in Figure 4. Comments are noted in the call-out boxes. Laboratory Services #2 ABN Specialising in the Analysis of Compost and Products Containing Recycled Organics NATA accreditation. Laboratory has a quality system in place and has expertise in required tests. 124 King St Tel: (02) Travell NSW 1111 Fax: (02) Sample identification provided. Evidence of internal record keeping. Testing methods specified. Analysis checked by a second person Laboratory Services #2 is a NATA accredited laboratory with expertise in testing to AS 4454, AS 3743, AS 4419 and AS Note: All results and recommendations assume that samples(s) provided are representative of bulk material. TEST REPORT: Nutrient assessment of compost Date sample received: 12/12/2002 Sample identification: Sample condition: Compost, moist (fresh as required) Client: Mr John Citizen Quality Compost Products Pty Ltd 101 Thine Rd Timber NSW 0101 Test(s) required: Basic nutrient assessment Product compliance requirements: Composted soil conditioner Testing methodology: Australian Standard AS 4454 (2002) TEST UNIT RESULT QC(%) 1 AS4454 COMMENTS ph ph units Pass Conductivity ds/m No limit 2 Pass Ammonium-N mg/l <300 Pass Nitrate-N mg/l >10 3 Pass Total N % >0.8 See note 4 Notes: 1. Tests were performed with reference to an internal standard for quality control (QC) purposes. QC results within 3%of the range of internal standard (97-103%) are acceptable. 2. See Summary and Recommendations on page See Summary and Recommendations on page See Summary and Recommendations on page 2. Signed: Robin F Thomas Chemist Checked by: Sue Smith Quality Manager *** Customer Support Line *** Page 1 of 2 Necessary limitations of test is specified. Sample condition specified Type of test required, product type, level of compliance and methodology used. Comparison to standard provided. Standard units are used. Internal QC results reported. Interpretation of results based on standard. Additional customer support available. Summary and recommendations provide (page 2). Size of report specified. No pages missing

45 Figure 4. Page 2 of the good laboratory report example as shown in Figure 3. This page provides an interpretation of the laboratory results and recommendations based on the testing done. Comment noted in the call-out box. Laboratory Services #2 ABN Specialising in the Analysis of Compost and Products Containing Recycled Organics 124 King St Tel: (02) Travell NSW 1111 Fax: (02) Laboratory Services #2 is a NATA accredited laboratory with expertise in testing to AS 4454, AS 3743, AS 4419 and AS Note: All results and recommendations assume that samples(s) provided are representative of bulk material. Good clear interpretations and recommendations provided to the client. SUMMARY AND RECOMMENDATIONS The sample supplied meets the tested criteria for a composted soil conditioner as specified in AS 4454 (2002) Composts, Soil Conditioners and Mulches. For compliance to AS 4454, a full test would need to be performed. Note 2: There is no electrical conductivity (EC) requirement for a soil conditioner to pass AS However, for soil conditioners with and EC greater than 1 ds/m, application rates to soil need to be limited and be stated on the primary package. Based on the sample analysed, application rate should be limited to <15 L/m 2 for sensitive plants and <60 L/m 2 for tolerant plants. Note 3: Ammonium levels are acceptable but nitrate levels are low. This indicates that the composted soil conditioner is not fully mature. Storage under aerated conditions would improve nitrate levels. To pass AS 4454, this is not required. Note 4: Total N is less than that required in AS 4454 if a claim to plant nutrition is claimed. In this case, a claim to plant nutrition cannot be made on the primary package. Signed: Robin F Thomas Chemist Checked by: Sue Smith Quality Manager *** Customer Support Line *** Page 2 of

46 Notes: Important references ARMCANZ Water Technology Committee (1995). Australian Guidelines for Sewage Systems Biosolids Management. Occasional Paper WTC No. 1/95. NSW EPA (1997). Environmental Guidelines: Use and Disposal of Biosolids Products. NSW Environment Protection Authority, Chatswood, NSW. Recycled Organics Unit (2002). Guide to Developing a Process Control System for a Composting Facility. Second Edition. Recycled Organics Unit, internet publication: Standards Australia (1996). Australian Standard/New Zealand Standard 4422 Playground surfacing specifications, requirements and test method. Jointly published by Standards Association of Australia and Standards Association of New Zealand, Homebush, NSW, Australia. Standards Australia (2002). AS 3743 Potting mixes. Standards Association of Australia, Homebush, NSW, Australia. Standards Australia (2002). AS 4419 Soils for landscaping and garden use. Standards Australia, Homebush, NSW. Standards Australia (2002). AS 4454 Composts, soil conditioners and mulches. Standards Australia, Homebush, NSW. Produced by: Recycled Organics Unit PO Box 6267 The University of New South Wales Sydney Australia 1466 Online contact details: ROU Internet Angus Campbell Whilst all care is taken in the preparation of this Information Sheet, the information provided is essentially general in nature and the Recycled Organics Unit disclaims all liability for any error, loss or other consequence which may arise from application of the information in any specific situation. Recycled Organics Unit 2003 Acknowledgement The author would like to extend a special thankyou to members of the peer review committee for critically evaluating this document: Dr Trevor Gibson, NSW Agriculture; Dr Kevin Wilkinson, Agriculture Victoria; Mr Darren Bragg, Resource NSW; Mr Garry Kimble, Quality Assurance Services; Dr Martin Line, University of Tasmania; Mr Chris Rochfort, EC Sustainable Environment Consultants and Dr Pam Pittaway, University of Southern Queensland

47 Information Sheet No. 3-6 Biosolids guidelines: Raw materials and compost product quality Information Sheet No. 3-6 Third Edition 2007 Inside This Sheet 1 Quality of biosolids and risk minimisation based regulations Relevance to composting 2 Definitions Buyer beware 3 Quality of other raw material inputs 4 Pasteurisation risk minimisation for organic products Important references Acknowledgement Quality of biosolids and risk minimisation based regulations Biosolids are organic solids or semisolids produced by municipal sewage treatment processes. The solids component of biosolids is rich in organic matter and essential plant nutrients such as nitrogen and phosphorus. Thus, biosolids can be useful input materials for composting production (Plate 1). Biosolids can be combined with the woody materials such as woody garden organics, wood & timber, or sawdust for re-processing into a range of quality composted products, commonly with relatively high nutrient levels. Biosolids can contain significant loadings of pathogenic microorganisms, heavy metals and a variety of chlorinated hydrocarbons and other chemical residues that can cause toxicity in plants and animals if incorrectly handled, processed or recycled to the environment. NSW EPA (1997) published a biosolids classification framework that can help evaluate the quality of biosolids. Classification of biosolids into quality grades and specification of permissible uses helps recyclers of these materials whether they be land appliers or composters to determine the suitability for re-use. The quality of biosolids used in composting systems will affect the quality of the resulting compost, and of all other products blended from such compost. Attention to the quality of biosolids supplied by a sewage treatment plant is therefore an important process control step in a composting operation. Relevance to composting The NSW EPA Environmental Guidelines for the Use and Disposal of Biosolids Products (1997) uses a system for assessing the suitability of biosolids and derived products for land application. The system is based on gradings for contamination and stabilisation, and specifies permissible uses on this basis. Plate 1. Composting of biosolids and garden organics in turned windrows in NSW. Recycled Organics Unit 2003 ISBN Information for organic resource recovery, management, research & development, quality systems and training

48 Table 1. Classification of biosolids products (NSW EPA, 1997). Definitions Biosolids classification Unrestricted use Allowable land application use i) Home lawns and gardens ii) Public contact sites iii) Urban landscaping iv) Agriculture v) Forestry vi) Soil and site rehabilitation vii) Landfill disposal viii) Surface land disposal 2 Minimum quality grades Contaminant Stabilisation grade grade A A Biosolid Organic solids or semi-solids produced by municipal sewage treatment processes. Solids become biosolids when they come out of an anaerobic digester or other treatment process and can be beneficially used. Until such solids are suitable for beneficial use they are defined as wastewater solids. The solids content in biosolids should be equal to or greater than 0.5% weight by volume (w/v). Restricted use 1 Restricted use 2 i) Public contact sites ii) Urban landscaping iii) Agriculture iv) Forestry v) Soil and site rehabilitation vi) Landfill disposal vii) Surface land disposal 2 i) Agriculture ii) Forestry iii) Soil and site rehabilitation iv) Landfill disposal v) Surface land disposal 2 B C A B Composting The process whereby organic materials are pasteurised and microbially transformed under aerobic and thermophilic conditions for a period of not less than 6 weeks. Compost Product An organic product that has undergone controlled aerobic and thermophilic biological transformation to achieve pasteurisation and a specified level of maturity. Restricted use 3 Not suitable for use i) Forestry ii) Soil and site rehabilitation iii) Landfill disposal iv) Surface land disposal 2 i) Landfill disposal E 1 C 1 ii) Surface land disposal 2 D B Process Control Stringent and documented monitoring of all critical control points in a composting operation so as to minimise defects and make products which can be guaranteed to customers. Notes: 1. Biosolids products which are not contaminant or stabilisation graded are automatically classified Not suitable for use. 2. To be applied within the boundaries of sewage treatment plant site. Contaminant Grade Classification category used to describe the quality of biosolids products based on the concentration of constituent contaminants. Contaminant Grade A category used to describe the quality of a biosolids product based on the concentration of a range of constituent contaminants (e.g. heavy metals and chlorinated hydrocarbons). Grades are assigned from A (high quality) to E (low quality). Stabilisation Grade A category used to describe the quality of a biosolids product based on its level of pathogen reduction, vector attraction reduction and odour reduction. Grades are assigned from A (high quality) to C (low quality). Both contaminant and stabilisation grades are used to assess the Class of biosolid, which in turn determines the permitted uses and associated conditions (Table 1). Lower quality biosolids (e.g. Contaminant Grade C) can be used as input material for compost production, but the Biosolids are combined with a sufficient quantity of other complimentary materials (e.g. garden organics) to reduce the total concentration of contaminants in the resulting compost to acceptable levels. Stabilisation Grade Classification category used to describe the quality of a biosolids products based on microbiological characteristics, vector attraction and potential to generate odours. Pathogen reduction A process that kills disease causing organisms, including certain bacteria, protozoa, viruses and viable helminth ova. Vector Attraction Reduction A process capable of reducing the attraction of insects and animals, such as flies, mosquitos and rodents, to putrescible organic materials and which may spread pathogens. Continued on Page

49 Compost and related products manufactured from Biosolids need to comply with the chemical and organic contaminant requirements, and other conditions specified in the relevant Biosolids guidelines (NSW EPA, 1997), and with any other relevant regulatory requirements to comply with the Australia Standard, AS 4454 (2003). AS 4454 does however specify that, for retail sale, all compost products shall meet the requirements of the unrestricted classification specified in the appropriate regulation. Note that biosolids that have not been assessed for contaminant or stabilisation grading are automatically classified Not Suitable for Use. Also note that surface land disposal only refers to the process of applying biosolids within the boundaries of a sewage treatment plant site. In most cases, the sewage treatment plant operator conducts biosolids grading. Biosolids must be classified before transport from the sewage treatment facility to an off-site reprocessing operation, unless approval is obtained from NSW EPA. Buyer beware Even though a batch of biosolids may be classified as suitable for unrestricted use, the batch may still be unsuitable for the manufacture of highly specific products that have a low tolerance to contaminant levels. Thus, the quality of biosolids used needs to be assessed on a batch per batch basis to ensure they are suitable for a specific application. The NSW EPA Biosolids Guidelines (1997) only provides a basic minimum standard as to acceptable contaminant and stabilisation levels for biosolids that are suitable for reuse. The Biosolids Guidelines, therefore, are not necessarily useful for the purpose of establishing whether a batch of biosolids are suitable for the manufacture of a particular product or application. For example, seed raising mixes need to have a low soluble salt content, or low electrical conductivity (Standards Australia AS 3743, 2002). Biosolids used to produce composts that form the basis of seed raising mix products should therefore have a low electrical conductivity (among other requirements). The quality of biosolids used in composting operations, therefore, very much depends on the required performance characteristics of the compost products manufactured. Compost operations accepting biosolids materials for reprocessing should ensure minimum quality requirements are specified in contract with the biosolids supplier. Confirmation of biosolids quality should be an essential process control measure prior to receival for composting. The NSW EPA Environmental Guidelines for the Use and Disposal of Biosolids Products (1997) should be consulted to determine the quality of biosolids that suitable for used as input materials for composting. The relevant national standards are the Guidelines for Sewerage Systems - Biosolids Management (Natural Resource Management Ministerial Council, 2002). Quality of other raw material inputs The quality of raw material inputs directly impacts on the quality of compost products manufactured. A number of chemical, physical and biological contaminants can negatively impact on the quality of raw materials used for composting. Chemical contamination can include heavy metals, chlorinated hydrocarbons, pesticides and other chemical resides. Surface Land Disposal Continued from Page 2 Waste disposal area within sewage treatment plants (licensed and approved by the EPA) where the biosolids are not buried but applied to the surface at rates that exceed the requirements of beneficial land application or where the application has no intended beneficial use. Raw material Any organic material that is suitable for composting that has not been subject to a composting process, and may contain weed propagules and pathogenic microorganisms. Pasteurisation The process whereby organic materials are treated to kill plant and animal pathogens and weed propagules. Pasteurised Product Organic materials resulting from the controlled microbiological transformation of organic materials under aerobic and thermophilic conditions such that the whole mass of constantly moist material is subjected to at least 3 consecutive days at a minimum temperature of 55C. Biological contamination can include: human, animal or plant pathogens, and weed propagules (viable weed seeds and vegetative cuttings capable of regrowth). Physical contamination can include: metal, stones, plastic, glass and clods of clay. The risk associated with spreading weed propagules and pathogenic microorganisms in the environment is substantial when raw organic products are not pasteurised prior to use (Recycled Organics Unit, 2002; Standards Australia AS 4454, 2003). All organic products should preferably be pasteurised to eliminate harmful pathogens and weed propagules, unless a specialised application is required (e.g. soft fall mulch see Information Sheet No. 3-7)

50 Pasteurisation risk minimisation for organic products Pasteurisation is a process of destroying weed seeds and pathogenic microorganisms using heat and moisture. Pasteurisation of raw materials can be effectively achieved in well-managed composting systems. Pasteurisation occurs at 55-70C. This process is not sterilisation, where all microorganisms are destroyed. Pasteurisation kills off pathogenic microorganisms and weed propagules because they are sensitive to high temperatures. Acceptable chemical and physical contamination of raw materials that are used for composting will depend on the performance characteristics required and market acceptance of the manufactured compost products. Therefore, the quality of raw organic products processed at a composting facility needs to be assessed and managed so that the quality of the resulting compost products can be consistently maintained. Notes: Important references Natural Resource Management Ministerial Council (2002) Draft Guidelines for Sewerage Systems - Biosolids Management. Department of Agriculture, Fisheries and Forestry, Canberra, Australia. (Document available from ) NSW EPA (1997). Environmental Guidelines: Use and Disposal of Biosolids Products. NSW Environment Protection Authority, Chatswood, NSW. ( ) Recycled Organics Unit (2002). Guide to Developing a Process Control System for a Composting Facility. Second Edition. Recycled Organics Unit, internet publication: Standards Australia (2003). AS Potting mixes. Standards Association of Australia, Homebush, NSW, Australia. Standards Australia (2003). AS Composts, soil conditioners and mulches. Standards Association of Australia, Homebush, NSW, Australia. Acknowledgement The authors would like to extend thanks to members of the peer review committee for critically evaluating this document: Dr Trevor Gibson, NSW Agriculture; Dr Kevin Wilkinson, Agriculture Victoria; Mr Darren Bragg, Resource NSW; Mr Garry Kimble, Quality Assurance Services; Dr Martin Line, University of Tasmania; Mr Chris Rochfort, EC Sustainable Environment Consultants and Dr Pam Pittaway, University of Southern Queensland. Produced by: Recycled Organics Unit PO Box 6267 The University of New South Wales Sydney Australia 1466 Online contact details: ROU Internet Angus Campbell Whilst all care is taken in the preparation of this Information Sheet, the information provided is essentially general in nature and the Recycled Organics Unit disclaims all liability for any error, loss or other consequence which may arise from application of the information in any specific situation. Recycled Organics Unit

51 1 2 3 Information Sheet No. 3-7 Third Edition 2007 Inside This Sheet Playground surfacing Organic products suitable for playground surfacing Relevance to composting Assessing Head Injury Criteria (HIC) Values and Critical Fall Heights for Mulched Products Definitions Testing to Meet Requirements of AS/NZS Important references Acknowledgement Information Sheet No. 3-7 Manufacturing Quality Products Introduction to Australian Standard AS/NZS for playground surfacing Playground surfacing Over the last few years in Australia and New Zealand there has been an increased interest in the use of soft surfacing underneath and around playground equipment. This surfacing is variously known as soft fall, soft surfacing and undersurfacing. Adequate surfacing is required underneath and around all playground equipment from which a child might fall, in order to reduce the effects of those falls. Mulches with certain physical attributes classified as loose fill materials can be successfully used as soft fall. Playground surfacing, therefore, represents a potentially valuable market for recycled organic products. The Australian and New Zealand Standard for Playground Surfacing (AS/NZS ) gives a method for assessing the suitability of materials for use as soft fall. The Standard simply outlines a method of determining a head injury criteria (HIC) value, which is a calculation of the severity of a deceleration impact on a child s brain during a fall. The Standard also sets out requirements for the depth of undersurfacing, and a guide to allowable free fall heights from playground equipment onto such surfacing. Adequate surfacing will minimise the incidence and severity of head injury, and will also reduce the occurrence of bone injury. Organic products suitable for playground surfacing The most suitable organic material for use as soft fall is soft and fluffy size reduced bark, containing no physical contamination and no woody particles that have an ability Plate 1. Soft-fall applied around playground equipment. The soft-fall material pictured below has been prepared from pine bark and is commercially available in New South Wales. Recycled Organics Unit 2003 ISBN Information for organic resource recovery, management, research & development, quality systems and training

52 to splinter and cause injury (Plate 1). Obviously, soft fall mulch needs to be contaminant free, as serious injury can result during a fall if the mulch is contaminated with hard materials such as plastics, glass, metal and stones. Relevance to composting Unlike mulches that are used in landscaping or gardening, mulches used as soft fall in playgrounds do not require pasteurisation to eliminate weed seeds and plant pathogens. Soft fall mulches are applied in confined playground areas where there is minimal risk of weed seeds and plant pathogens impacting on the environment. Organic materials that have been pasteurised or composted, however, are not likely to be suitable for use as soft fall. This is because during the decomposition process physical structure decreases (e.g. porosity decreases and bulk density increases), making them less able to absorb or attenuate an impact during a fall. Assessing Head Injury Criteria (HIC) Values and Critical Fall Heights for Mulched Products Assessment of HIC and g max values of a mulch allows the calculation of critical fall height. g max is the maximum deceleration experienced during an impact. Critical fall height is defined as the minimum free fall height above which head injury is likely to occur with a particular type of soft fall material. Materials differ in their ability to absorb the impact of a fall. Some materials can better absorb the impact of a fall, and are therefore suitable for use as soft fall surfacing beneath playground equipment where large falls can occur. Materials with a lower ability to absorb the impact of a fall can be used as surfacing beneath playground equipment where only small falls can occur. HIC and g max values can be determined on-site with test fall headform, accelerometer and impact measurement equipment. Such tests should be performed by an accredited laboratory or testing service. The critical fall height of a soft fall mulch or the maximum height a soft fall mulch can be used to safely absorb the impact of a fall is established when the HIC value approaches 1000 or when g max approaches 200. Performance data pertaining to a batch of soft fall mulch should be provided to customers. Such information should include: Anticipated service life of the product when installed and maintained in accordance with the supplier s recommendations; Flammability of the material; and Instructions about correct installation, maintenance and inspection procedures. Further details regarding the testing and use of soft fall materials for playground surfacing can be obtained from AS/NZS 4422 (1996). Testing to Meet Requirements of AS/NZS To demonstrate compliance with the Standard, samples of product need to Definitions Surfacing The surface of a playground from which the use of the equipment commences. Loose Fill Material Material of a particulate nature, installed to a specific depth, absorbing the energy of an impact through its displacement. Head Injury Criteria Value (HIC) A measure of the impact severity that considers the duration over which the most critical section of the deceleration pulse persists as well as the peak level of that deceleration. Free Fall Height The greatest vertical distance between a part of the equipment to which the child has reasonably foreseeable access, and the surface or part of the equipment beneath. g max The multiple of g (Earth s gravity) that represents a maximum deceleration experienced during an initial impact. be periodically tested by an independent off-site laboratory. Further details regarding off-site laboratory testing can be found in Information Sheet No Further details regarding product certification systems can be found in Information Sheet No

53 Notes: Important references Standards Australia (1996). Australian Standard/New Zealand Standard 4422 Playground surfacing specifications, requirements and test method. Jointly published by Standards Association of Australia and Standards Association of New Zealand, Homebush, NSW, Australia. Acknowledgement The authors would like to extend a special thankyou to members of the peer review committee for critically evaluating this document: Dr Trevor Gibson, NSW Agriculture; Dr Kevin Wilkinson, Agriculture Victoria; Mr Darren Bragg, Resource NSW; Mr Garry Kimble, Quality Assurance Services; Dr Martin Line, University of Tasmania; Mr Chris Rochfort, EC Sustainable Environment Consultants and Dr Pam Pittaway, University of Southern Queensland. Recycled Organics Unit 2003 Produced by: Recycled Organics Unit PO Box 6267 The University of New South Wales Sydney Australia 1466 Online contact details: ROU Internet Angus Campbell Whilst all care is taken in the preparation of this Information Sheet, the information provided is essentially general in nature and the Recycled Organics Unit disclaims all liability for any error, loss or other consequence which may arise from application of the information in any specific situation.

54 Information Sheet No. 3-8 Producing Quality Compost Introduction to Australian Standard AS 4454 (2003) composts, soil conditioners and mulches Information Sheet No. 3-8 Third Edition 2007 Inside This Sheet What is the Australian Standard AS 4454? Why is a product standard needed, and benefits of compliance? What products are covered in AS 4454? Definitions What products are excluded from AS 4454? Overview of product quality guidelines 4 Overview of best practice guidelines for composting and vermiculture systems 5 Testing to meet requirements of AS 4454 Key changes to revised AS 4454 (2003) Important references What is the Australian Standard AS 4454? The Australian Standard AS 4454 contains guidelines to provide manufacturers, local government bodies, consumers and growers with: minimum requirements for the physical, chemical and biological properties of composts, soil conditioners and mulches; and labelling and marking requirements, in order to facilitate beneficial recycling and use of organic materials with minimal adverse impact on the environment and public health. The standard also sets out best practices to assist processors to consistently produce quality composts, soil conditioners, mulches and vermicasts (Plate 1). Why is a product standard needed, and benefits of compliance? There are composted products in the market place that do not live up to consumer s expectations. Some tend to be variable in quality, and others can damage plants when applied as a soil conditioner or a mulch. One way a manufacturer can assure the quality of a product is to have it tested and/or certified to the criteria specified in AS Formal product certification to the Australian standard allows the manufacturer of a compost, soil conditioner or mulch to label their product with the widely recognised Australian standard five ticks logo. Australian standard certification ticks allows the differentiation of products in the market place. Consumers can buy a certified product with confidence, with the assurance that the product meets quality standards and is safe to use. Plate 1. A composted soil conditioner certified under AS 4454 (2003) for composts, soil conditioners and mulches. This product is suitable for incorporating into soil to improve soil conditions and plant growth. Acknowledgement Recycled Organics Unit 2003 ISBN Information for organic resource recovery, management, research & development, quality systems and training

55 The best chance of producing a compost, soil conditioner or mulch that consistently conforms to the Australian Standard is to control the manufacture with documented management system, such as an ISO 9001 quality management system. Best practice principles can be used to develop and implement procedures to maintain required product quality, and to minimise the impact of operations on the environment. The success of a composting operation is dependent on: systematic operational practices, quality control, and meeting customer requirements (Recycled Organics Unit, 2002). AS 4454 can contribute to achieving these goals. What products are covered in AS 4454? The standard provides quality guidelines for two major categories of products: Pasteurised products have been processed to achieve effectively pasteurised yet are still immature and relatively unstable. Composted products have been processed more thoroughly to achieve pasteurisation & maturity. Products defined in the standard are manufactured by controlled aerobic and thermophilic biological transformation to achieve pasteurisation and a specified level of maturity. Before organic materials are used as soil conditioners or mulches, they should be pasteurised to kill any harmful bacteria or plant pathogens. The pasteurisation process achieved through keeping materials at a minimum of 55C for at least three consecutive days will also destroy or reduce the viability of many weed seeds. Pasteurisation of materials can be achieved over a short period of processing, and pasteurised products can therefore still be unstable. Whilst commonly considered as lower grade products, they do not have the risk of distributing plant disease organisms or weed seeds which can be spread via unprocessed products such as leaf mulch or manure. Composted products are processed for significantly longer periods under aerobic (high oxygen) and thermophilic (>55C) conditions until the compost is stable and mature. This involves regular turning of compost piles or blowing air into the composting mass. As with pasteurised products, composted products are free of plant pathogens, bacteria harmful to humans or animals, and plant propagules (weeds). In addition, mature composts can be applied at greater rates and without risk of damage to plants as the mature product does not continue to break down rapidly, does not have potential for negative impact on plant growth, and provides nutrients to plants. The (solid) product of vermiculture operations vermicast is also now included in the AS This product can be produced from compostable organic materials that have achieved pasteurisation through composting or some other process. Where a dedicated pasteurisation process has not been used in the manufacturing of vermicast, a plant propagule test is required to demonstrate that the product does not contain viable plant propagules. Within this standard, vermicast may be classified as a pasteurised vermicast or pasteurised soil conditioner, and requires 90% of particles to pass through a 1.18 mm sieve. However, solid vermicast products can also be tested and certified as composted mulch or composted soil conditioner provided they meet the specified requirements. Definitions Compost An organic product that has undergone controlled aerobic and thermophilic biological transformation to achieve pasteurisation and a specified level of maturity. Soil Conditioner Any composted or pasteurised organic material that is suitable for adding to soils. This term also includes soil amendment, soil additive, soil improver and similar terms, but excludes polymers which do not biodegrade, such as plastics, rubber and coatings. Soil conditioners may be either composted soil conditioners or pasteurised soil conditioners. Soil conditioner has not more than 15% by mass of particles with a maximum size above 15 mm. Vermicast Solid organic material resulting from the biological transformation of compostable organic materials in a controlled vermiculture process. Mulch Any pasteurised organic product (excluding polymers which do not degrade such as plastics, rubber and coatings) that is suitable for placing on soil surfaces. Mulch has at least 70% by mass of its particles with a maximum size of greater than 15 mm. Quality Management System An integrated policy and set of procedures an organisation establishes to systematically ensure it products consistently achieve consumer satisfaction. Pasteurised Product Organic material resulting from the controlled microbiological transformation of organic materials under aerobic and thermophilic conditions such that the whole mass of constantly moist material is subjected to a least 3 consecutive days at a minimum temperature of 55C. Pasteurisation The process whereby organic materials are treated to kill plant and animal pathogens and weed propagules. Continued on Page

56 Figure 1. The six products covered in the Australian Standard for composts, soil conditioners and mulches (Standards Australia AS 4454, 2003). These products are divided into two main categories: composted products and pasteurised products. Composted products command a high price in the market than pasteurised products as they are more fully decomposed, less likely to bind or immobilise nutrients when applied or incorporated into soil, and better able to support plant growth. Soil conditioners, fine mulch and mulches Pasteurised products and composted products are further divided in this standard into soil conditioners (for incorporation into soil), fine mulches and mulches (both for surface application). This division is based mainly on particle size. Seven products are defined and specified in this standard, including: composted soil conditioner composted fine mulch composted mulch pasteurised soil conditioner pasteurised fine mulch pasteurised mulch pasteurised vermicast. These AS 4454 product categories are shown also in Figure 1 above. In the 2003 edition of this standard, the particle size specification for soil conditioners and fine mulches has been revised. A 16mm sieve is used to assess compliance. Soil conditioners are required to have less than 20% (by mass) of their particles greater than 16 mm (ie. > 80% must pass through the 16mm sieve). Fine mulches are required to have more than 20%, but less than 70% (by mass) of their particles with a diameter greater than 16 mm (ie < 70% retained by the 16mm sieve). Mulches are coarse products, as they are made up of equal to or more than 70% (by mass) of particles with a size greater than 16 mm (ie > 70% retained by the 16mm sieve). Mulches are only for surface application on top of soils. What products are excluded from AS 4454? Shredded garden organics (sometimes referred to as raw mulch, leaf mulch or chipped garden waste) are excluded from the standard, unless they have been subjected to a pasteurisation or composting process. This is because these raw materials have a high probability of containing plant propagules and pathogens. Also excluded are home composting products for self use, organic fertilizers, liquid organic wastes, liquid seaweed products, non-organic mulches (eg gravel), non-organic soils and soil conditioners (eg. sand or gypsum), non-compostable organic materials (eg. plastics), materials variously described as 'compost starters' and 'activators', and vermicast that has not been subjected to pasteurisation or composting (or an equivalent process). AS 4454 is not specifically concerned with the source of compostable organic materials from which products are manufactured, it focuses on physical, chemical and biological specifications for the defined categories of products. Overview of product quality guidelines The standard specifies minimum quality requirements for the seven defined products

57 Tests are specified for a range of quality parameters to assess different physical and chemical characteristics of the product. The extent of testing required to demonstrate conformance depends on the type of product. The number of tests that are required for assessing soil conditioners and fine mulches is greater than the number required for (coarser) mulches. The performance requirements for soil conditioners are more stringent than the equivalent performance requirement for mulches in a number of characteristics that are tested (eg. moisture content; sodium; plant toxicity). The performance requirements for composted products are higher than the equivalent performance requirements for pasteurised products in a number of characteristics that are tested (eg. Ammonium-N; Nitrate-N; maturity self heating). A greater number of parameters are tested for soil conditioners because they tend to be mixed into soil where they can more directly affect soil nutrients and the availability of oxygen in the root zone of plants, and are more likely to affect soil and plants if not properly composted or inappropriately applied. Although fine mulches are not mixed with soil, their small particle size does result in some mixing with surface soil over time. The risk of such damage occurring through inappropriate application of coarse mulches is lower. Overview of best practice guidelines for composting and vermiculture systems AS 4454 also contains information on best practice for the operation and management of common composting systems (Appendix N). The revised 2003 edition contains a best practice guideline for managing vermiculture systems (Appendix O). The inclusion of vermicast is the world-first formal standard for vermiculture products. This standard provides basic guidelines for Turned Piles, Aerated Static Piles, Windrows with or Without Aeration, In-vessel and vermiculture systems. The purpose of these best practice guidelines is to inform the consistent production of quality products. Key monitoring procedures are detailed to support effective process control and the consistent production. Testing to meet requirements of AS 4454 Appendix P in this standard specifies the means of demonstrating compliance with AS Certified products provide the highest level of quality assurance and confidence in product quality. Product certification also provides the greatest protection from potential legal liability for the processor. Whilst manufacturers can claim that their products comply with the requirements of the standard without being certified by an accredited third party (such as SAI Global), such claims must be backed up with evidence required to prove these claims. Without such evidence, manufacturers are likely to be in breach of trade practices legislation and regulations, and therefore potentially liable for significant penalties. The absence of a structured management system (such as an AS/NZS ISO 9001 compliant quality management system, which would also need to be evidenced), the only potentially valid option for demonstrating compliance is the testing of each batch of product for Continued from Page 2 Composting The process whereby organic materials are pasteurised and microbially transformed under aerobic and thermophilic conditions for a period of not less than 6 weeks to achieve a specified level of maturity. Turned Pile System of composting involving the periodic turning of piles of organic matter with mechanical equipment (e.g. front-end loaders or specialised windrow turners) between 1.5 and 3 m in height. Turning assists in: aeration and oxygen re-supply; eliminating odours; reducing consolidation, and moisture and nutrient re-distribution. Aerated Static Pile Forced aeration method of composting in which a free standing pile is aerated by a blower moving air through perforated pipes located beneath the pile. Windrow with or Without Aeration System of composting involving the aeration of horizontally extended piles formed by a front-end loader or windrow turner. Extended piles are generally 1.5 to 3 m in height, and length is limited by the size of the composting pad. Aeration can be achieved by mechanical turning and/or the delivery of air from the base of the windrow (see aerated static pile). In-vessel A containerised unit in which vermiculture, compost or anaerobic digestion-based processes are performed. Containers vary in size, configuration, degree of automation and level of process control. In-vessel systems are often used for treatment of putrescible organics in populated areas as they have minimal or no significant impact on the environment (e.g. through the generation of odour, leachate or attraction of pests or vermin). Vermiculture System of stabilising organic materials under controlled conditions by specific worm species and microorganisms under mesophilic temperatures. Commercial vermiculture systems include: windrows or beds; stackable trays; batch-flow containers, and continuous flow containers

58 which compliance with the standard is being claimed. To demonstrate compliance with the standard, batch testing samples of product would need to be tested by an independent off-site laboratory. Further details regarding off-site laboratory testing can be found in Information Sheet No Further details regarding product certification systems can be found in Information Sheet No Key changes to revised AS 4454 (2003) The key changes made to the revised Australian Standard AS 4454 (2003) are summarised below: Changes to definitions Modification of the heavy metal contamination requirements. [NOTE: this refers to section 2.1 of the Standard, which allows for compost products derived from biosolids to comply with AS 4454, so long as they also adhere to the requirements of the applicable biosolids regulations]. Modification of the methods for determining wettability and toxicity. Addition of a test for the presence of plant propagules. Admission of vermicast to the Standard, subject to its passing a sieve test for identification, and a new incubation test to determine their plant propagule content. Deletion of a requirement to determine nitrogen drawdown index. Modification of the soluble nitrogen requirements as a guide to product maturity. The self-heating test is now mandatory for composted soil conditioners. This test assesses whether compost is sufficiently mature via monitoring rise in temperature. The test is a simulation of turning a compost pile (containing suitable moisture) and monitoring temperature. If the core temperature does not rise above 40 C, the compost is deemed to be sufficiently mature. This principle provides a guide for processors to assess when composts are ready for sampling and quality testing simply by using a compost thermometer. Notes: Important references Recycled Organics Unit (2002). Guide to Developing a Process Control System for a Composting Facility. Second Edition. Recycled Organics Unit, internet publication: Standards Australia (1999). AS 4454 Composts, soil conditioners and mulches. Standards Australia, Homebush, NSW. Standards Australia (2003). AS 4454 Composts, soil conditioners and mulches. Standards Australia, Sydney, NSW. Acknowledgement The authors would like to extend thanks to members of the peer review committee for critically evaluating this document: Dr Trevor Gibson, NSW Agriculture; Dr Kevin Wilkinson, Agriculture Victoria; Mr Darren Bragg, Resource NSW; Mr Garry Kimble, Quality Assurance Services; Dr Martin Line, University of Tasmania; Mr Chris Rochfort, EC Sustainable Environment Consultants and Dr Pam Pittaway, University of Southern Queensland. Recycled Organics Unit 2003 Produced by: Recycled Organics Unit PO Box 6267 The University of New South Wales Sydney Australia 1466 Online contact details: ROU Internet Angus Campbell Whilst all care is taken in the preparation of this Information Sheet, the information provided is essentially general in nature and the Recycled Organics Unit disclaims all liability for any error, loss or other consequence which may arise from application of the information in any specific situation

59 Information Sheet No. 3-9 Manufacturing Quality Products from Compost Introduction to Australian Standard AS for potting mixes 1 2 Information Sheet No. 3-9 Third Edition 2007 Inside This Sheet What is the Australian Standard AS ? Benefits from using compost in potting mixes Two potting mix quality categories Definitions What range of potting mixes are included in AS ? Overview of potting mix quality guidelines 3 Testing to meet requirements of AS Important references 4 What is the Australian Standard AS ? The Australian Standard AS contains guidelines to assist the recycled organics industry to produce quality potting mixes. The overall objective of the standard is to provide manufacturers, educational institutions, consumers and growers with a set of minimum requirements which will ensure that potting mixes can germinate seeds, grow seedlings, strike cuttings and maintain plant growth. The standard specifies physical, chemical, biological and labelling requirements for potting mixes packaged for resale. Potting mixes of both regular and premium quality are covered. Requirements are also included for specialist potting mixes labelled as suitable for African violets, bulbs, hanging baskets, seedlings, orchids, acid-loving plants and plants that are sensitive to phosphorus. Given the beneficial effect that composts impart to potting mixes, formulation of composts into potting mixes can be a potentially profitable method of value adding to composted organics. Benefits from using compost in potting mixes The increasing price of peat in many countries in the late 1980 s resulted in the widespread use of recycled organic materials as a substitute for peat in potting mixes. Composts are an effective substitute for peat because the organic fraction: absorbs and releases water; slowly releases nutrients; assists in nutrient retention; and suppresses the growth of plant pathogens (Hoitink and Fahy, Acknowledgement Plate 1. A regular potting mix certified under AS 3743 (2002) for potting mixes. The mix contains composted garden organics, peat, sand and a wetting agent. Recycled Organics Unit 2003 ISBN Information for organic resource recovery, management, research & development, quality systems and training

60 1986; Handreck and Black, 1999). Potting mixes formulated with compost are often combined with inert material(s) to improve structural stability and air-filled porosity. These may include: coarse sand; gravel; perlite; vermiculite; plastic foams; clay pellets; rockwool; scoria; pumice; diatomite and lignite (Handreck and Black, 1999). Composts added to potting mixes usually have a specific particle size range to ensure that the mix has an adequate level of air-filled porosity. Composts used in potting mixes also tend to be mature, thus minimising nitrogen drawdown and subsidence (or compression) in the pot. Use of mature compost in potting mixes in many cases is important as immature composts can be toxic to plants. AS provides a quality guideline for potting mixes, whether they are formulated with compost, peat or any other suitable type of material. Two potting mix quality categories One way a manufacturer can guarantee the quality of a potting mix is to have it certified according to criteria set out in AS Australian Standard Certification then allows the manufacturer of a potting mix to label their product with the widely recognised Australian Standard five ticks logo. Australian Standard Certification ticks allows the differentiation of products in the market place. Consumers will buy a certified product with confidence, knowing that it is of a certain minimum quality. To produce a potting mix that meets the Australian Standard, a manufacturer must use a quality management system based on best practice principles. AS contains two product quality categories: regular potting mix and premium potting mix. Premium potting mixes differ from regular potting mixes based on some chemical and physical properties. Premium potting mixes have a higher soluble nitrogen content and thus a lower ability to deprive plants of soluble nitrogen. Such mixes can sustain plant growth for at least a month without added fertilisers if the use of the mix is commenced with 2 months of manufacture. Regular potting mixes require the addition of a balanced fertiliser from the time of potting. In addition, the water holding capacity and wettability of premium potting mixes is superior to that of regular grade potting mixes. What range of potting mixes are included in AS ? The standard provides quality guidelines for general and specialist potting mixes. Some of the products within these categories can be divided into regular and/or premium grades. The entire range of potting mix products covered in AS 3743 (2002) is shown in Figure 1. Please note that specific differences between the products are not reviewed in this Information Sheet. Readers should consult AS for specific chemical, biological and physical differences between these products. Definitions Potting Mix A growing medium suitable for the establishment and development of a wide range of plants in containers. Air-filled Porosity The percentage of air, by volume, in a potting mix after it has been watered and drained under standard conditions. Regular Potting Mix A potting mix with properties as outlined in AS and requiring the use of a balanced fertiliser from the time of potting. Premium Potting Mix A potting mix complying with the requirements as outlined in AS Most particularly, its soluble nitrogen content and low ability to deprive plants of soluble nitrogen enable it to sustain good plant growth for a least a month without added fertilisers if the use of the mix is commenced within 2 months of manufacture. Its nutrient levels, water holding capacity and wettability are superior to those of a regular grade mix. Overview of potting mix quality guidelines The standard states that potting mixes must meet a minimum level of quality. Tests for product quality assess different physical, chemical and biological properties of a mix. More specifically, the standard assesses the following quality parameters (Table 1)

61 Figure 1. Potting mixes covered by AS 3743 (2002). Please note that specific differences between the products are not reviewed in this Information Sheet. Readers should consult the standard for specific chemical, biological and physical differences between these products. Regular Premium General Potting Mix Seedling Specialist Potting Mix Orchid Low Phosphorus Acid African Violet Bulb Hanging Basket Regular Premium Testing to meet requirements of AS To demonstrate compliance with the Standard, samples of product need to be periodically tested by an independent off-site laboratory. Further details regarding off-site laboratory testing can be found in Information Sheet No Further details regarding product certification systems can be found in Information Sheet No

62 Table 1. Explanations of the physical, chemical and biological quality criteria for potting mixes as specified in AS Soil property Explanation Physical properties Air-filled porosity Total water holding capacity Wettability This is the percentage of air (by volume) in a potting mix after it has been watered and drained. Air filled porosity is important as this affects the ability of gases to diffuse in and out of a potting mix, which is required for good plant growth. Composts need to be combined with an inert substrate to maintain air-filled porosity over the life of the mix. This is the total amount of water (by weight) that a potting mix can hold after it has been watered and drained. Adequate water holding capacity is needed to provide water for plant consumption over time between waterings. This is the ease with which a potting mix may be re-wet once it has dried out. Some materials in potting mixes repel water when dry, and are difficult to rewet. This can seriously affect the ability of a mix to support plant growth. Wettability is measured as the time (minutes) taken for water to fully soak into a mix in the dry state. Chemical properties ph Electrical conductivity Ammonium, nitrate and chloride Nitrogen drawdown index This is a measure of the acidity or alkalinity of a potting mix. ph can affect the availability of nutrients in potting mixes, and plants vary in their tolerance to ph. This is a measure of how salty a potting mix is. Potting mixes that have a high electrical conductivity can slow the growth or kill plants by causing water stress. Ammonium and nitrate ions, referred to as soluble nitrogen, are required for plant growth. Potting mixes low in these nutrients require the addition of fertiliser to ensure that good plant growth is achieved. High ammonium concentrations, however, can be toxic to some plants. The concentration of chloride is important as this ion contributes to the salinity of a mix. Young plants are particularly sensitive to water stress caused by high concentrations of chloride. Potting mixes composed of organic materials that are not fully mature immobilise soluble nitrogen and can result in nitrogen deficiencies in plants. The nitrogen drawdown index measures nitrogen immobilisation in potting mixes. P, K, S, Ca, Mg, Ca/Mg, K/Mg, Na, Fe, Cu, Zn, Mg & B A range of macro- and micro-elements are required for sustained plant growth in potting mixes. The standard provides nutrient concentration ranges that are needed to produce potting mixes that are nutrient balanced. Biological properties Toxicity index Organic and inorganic toxins in potting mixes can reduce or even prevent plant growth. Toxicity index determines the toxicity of a mix relative to a reference mix that is non-toxic. Important references Handreck, K.A. and N.D. Black (1999). Growing Media for Ornamental Plants and Turf. University of New South Wales Press, Sydney, Australia. Hoitink, H. A. J. and P.C. Fahy (1986). Basis for the control of soilborne plant pathogens with composts. Annual Review of Phytopathology, 24: Standards Australia (2002). AS 3743 Potting mixes. Standards Association of Australia, Homebush, NSW, Australia. Produced by: Recycled Organics Unit PO Box 6267 The University of New South Wales Sydney Australia 1466 Online contact details: Acknowledgement The authors would like to extend a special thankyou to members of the peer review committee for critically evaluating this document: Dr Trevor Gibson, NSW Agriculture; Dr Kevin Wilkinson, Agriculture Victoria; Mr Darren Bragg, Resource NSW; Mr Garry Kimble, Quality Assurance Services; Dr Martin Line, University of Tasmania; Mr Chris Rochfort, EC Sustainable Environment Consultants and Dr Pam Pittaway, University of Southern Queensland. Recycled Organics Unit ROU Internet Angus Campbell Whilst all care is taken in the preparation of this Information Sheet, the information provided is essentially general in nature and the Recycled Organics Unit disclaims all liability for any error, loss or other consequence which may arise from application of the information in any specific situation.

63 Information Sheet No Manufacturing Quality Products from Compost Introduction to Australian Standard AS soils for landscaping and garden use Information Sheet No Third Edition 2007 Inside This Sheet What is the Australian Standard AS ? Benefits from using compost in soils What range of soils are included in AS ? Definitions Overview of soil quality guidelines Testing to meet requirements of AS Important references Acknowledgement What is the Australian Standard AS ? The Australian Standard AS contains guidelines to assist the recycled organics industry to produce quality soils for landscaping and garden use. The overall objective of the standard is to provide manufacturers, landscape architects, educational institutions, consumers and growers with a set of minimum requirements which will ensure that soils can culture and maintain plant growth. The standard specifies requirements for general purpose soils, top dressing, topsoil and landscaping mixes (e.g. low density soil, organic soil and soil blend), for domestic and commercial use, supplied in either bulk or bagged lots. The standard also provides guidance for the selection and use of soils. The requirements of this standard specify soils suitable for the vast majority of plants but do not cover soils for plants with special requirements, cricket pitch soils, other specialist sporting turf soils, on-site soils or fertilisers. Given the beneficial effect that composts impart to soils for landscaping and garden use, formulation of composts into soil can be a potentially profitable method of value adding to composted organics. Benefits from using compost in soils Extensive extraction of natural soils from grassland, bushland and cultivated land (soil mining) for use in urban landscaping and gardening during the last few decades has resulted in significant environmental damage. Exposed subsoils are extremely difficult to revegetate, due to a lack of fertile top soil which is needed to provide nutrients, moisture and a substrate for plant root development. Plate 1. An organic soil manufactured for general landscaping purposes. The product consists of approximately 30% (w/w) mature compost (<15 mm particle size), 20% sand (w/w) and 50% (w/w) natural soil. Recycled Organics Unit 2003 ISBN Information for organic resource recovery, management, research & development, quality systems and training

64 The use of recycled organic materials, such as compost, as a component of these mixes not only reduces demand on finite natural soil reserves, but can be associated with a number of benefits. Compost in soil mixes can: reduce overall bulk density, allowing for easier handling; improve total water holding capacity; improve air-filled porosity; improve nutrient levels; improve nutrient retention (through improved cation exchange capacity); and improve plant disease suppression properties (Hoitink and Fahy, 1986; Handreck and Black, 1999). To manufacture a particular type of soil for landscaping or garden use that complies with the standard, composts can be blended with sand and/or natural soils. AS provides a guideline as to how the quality of soils for landscaping and garden use can be assessed, and a basis for the manufacture of various soils for landscaping and garden use. The standard also assists manufacturers to select appropriate uses for the various types of soils made. What range of soils are included in AS ? The standard provides quality guidelines for three categories of soils. These are: Low density soil These types of soils tend to be composed mainly of organic materials (e.g. compost), and some sand and/or natural soil. They have a low bulk density ( kg L -1 ) and a moderately high organic matter content (10-40% by mass). Such soils tend to be used for rooftop gardens and in large landscape containers. The standard recommends that low density soils with an organic matter content greater than 20% and a bulk density of less than 0.3 kg L -1 should not be used in any outdoor landscaping situation, including onslab situations, and only in tubs and containers. This is because continuing decomposition of the organic matter in such highly organic materials will lead to slumping and subsidence which may not be acceptable in landscaped situations. As low density soils tend to be composed mainly of composts, such soils may require the addition of nitrogenous fertiliser if the composted fraction is low in available nitrogen (e.g. some composts prepared from woody garden organics). Addition of a nitrogenous fertiliser to low density soils that are low in nitrogen ensures that the soil will not cause nitrogen deficiency in plants. Organic soil These types of soils usually consist of natural soil and organic materials (e.g. compost). Most organic soils contain less compost than low density soils. Organic soils have a medium bulk density (>0.6 kg L -1 ) and a moderate organic matter content (15-25% by mass). Definitions General Purpose Soil A material consisting of natural soil, amended natural soil, a blend of sand and organic materials or a blend of sand, natural soil materials and organic materials, which is suitable for the culture of plants usually grown in domestic gardens and landscaped areas. Top Dressing A soil which is suitable for surface application to lawn. Topsoil A natural soil which is the original surface layer of soil from grassland, bushland or cultivated land. Low Density Soil Soil for use on an artificial base material, e.g. for a rooftop garden, or in large landscape containers. Such soils will usually be blends of mineral and organic components, and will typically have a bulk density in the range of 0.3 to 0.6 kg L -1. Organic matter content will generally be in the range 10% to 40% by mass. Organic Soil A general-purpose soil (normally an amended natural soil or soil blend) that has a bulk density of greater than 0.6 kg L -1, and with an organic matter content in the range 15% to 25% by mass. Soil Blend A general-purpose soil derived from the blending of two or more of: sand; natural soil material or organic materials and having a bulk density of greater than 0.7 kg L -1, and an organic matter content in the range 3% to 15% by mass. Natural Soil A soil that has been dug from the landscape and is presented for use with no more than minor amendment. This soil could be topsoil, subsoil or a mixture of them. Typically it will have a bulk density of greater than 0.7 kg L

65 Table 1. Explanations of the physical, chemical and biological quality criteria for soils for landscaping and garden use as specified in AS Soil property Explanation Physical properties Bulk density Organic matter Wettability Dispersibility Permeability (hydraulic conductivity) Texture Large particles Bulk density is a measure of mass per given volume. The density of soils increases as the proportion of the mineral fraction (e.g. clay and sand) increases. Composts, due to their lower density, can reduce the overall density of a soil, making it suitable for specialised applications (e.g. large landscaping tubs). The proportion of organic matter is important as this affects several physical and chemical properties of soil, such as bulk density, water retention, texture, permeability, ph and nitrogen drawdown. This is the ease with which a soil may be rewet once it has dried out. Some materials in soil mixes repel water when dry, and are difficult to rewet. This can seriously affect the ability of a soil to support plant growth. Wettability is measured as the rate of water infiltration per minute. AS states that low density soils, however, must be tested according to the wettability test described in AS This is a measure of a soils tendency to disperse after watering and to set hard after drying. Some clays exhibit these properties, and such soils tend to set hard on drying and have a very low level of air-filled porosity. Ideal soils are not dispersive and remain friable (crumbly) and open when wet or dry. Low density and organic soils do not require this test as they are highly friable due to their high organic matter content. This is a measure of a soils ability to transmit water. Soils with high clay contents usually have a low hydraulic conductivity, meaning that water slowly passes through them. Under high rainfall conditions such soils may become waterlogged, resulting in oxygen deficiencies in the root zone of plants, possibly resulting in plant death. This test only needs to be performed on natural soil or soil blends for the purpose of classifying the soil. Texture testing provides an indication to the amount of sand, silt and clay in a soil. The standard states that soils will not be contaminated with excessive amounts of large particles, such as bark, roots, clay lumps, stones or other solid materials. Required particle size ranges within the soil depends of the type of soil manufactured. Specific details can be obtained from the standard. Chemical properties ph Electrical conductivity Ammonium Nitrogen drawdown index This is a measure of the acidity or alkalinity of a soil. ph can affect the availability of nutrients in a soil, and plants vary in their tolerance to ph. This is a measure of how salty a soil is. Soils that have a high electrical conductivity can slow the growth or kill plants by causing water stress. Ammonium ions, or soluble nitrogen, is required for plant growth. However, when in excess, ammonium ions can be toxic to plant roots. Soils composed of organic materials that are not fully mature immobilise soluble nitrogen and can result in nitrogen deficiencies in plants. The nitrogen drawdown index measures nitrogen immobilisation in soils. Biological properties Toxicity index Organic and inorganic toxins in soils can reduce or even prevent plant growth. Toxicity index determines the toxicity of a soil relative to a reference soil that is non-toxic. Organic soils are used mainly for general landscaping, though the standard recommends that they not be applied to a depth of any more than 150 mm. This is because at greater depths, putrefaction of the lower layers is likely and this can damage plants. Damage to plants can occur through oxygen depletion in the root zone by continued microbial decomposition of the organic fraction present in the organic soil

66 Natural soil or soil blend These soils are composed mainly of natural soil excavated from the environment, or a soil blend with a very small fraction of organic material (e.g. compost). They tend to have a relatively high bulk density (>0.7 kg L -1 ) and a low organic matter content (3-15% by mass). Such soils tend to be used primarily for general landscaping. The clay content of these soils helps bind plant nutrients and organic matter when incorporated into an existing soil. Natural soils or soil blends with a clay content above 40%, however, are considered by the standard to be unsuitable for general landscaping purposes. This is due to the high bulk density, making handling difficult, and the high clay content which may deleteriously affect plant growth. High clay content soils tend to have low air-filled porosity, poor drainage, reduced water infiltration and susceptibility to water logging. These factors can seriously affect plant growth. Overview of soil quality guidelines As with other products manufactured from compost, they must meet some basic quality criteria. Soils should be free from any living parts (seeds, bulbs, corms, vegetative propagules etc.) of plants that are generally considered to be weeds. Tests for soil quality assess different physical, chemical and biological properties of a mix. These are briefly reviewed in Table 1. Testing to meet requirements of AS To demonstrate compliance with the Standard, samples of product need to be periodically tested by an independent off-site laboratory. Further details regarding off-site laboratory testing can be found in Information Sheet No Further details regarding product certification systems can be found in Information Sheet No Important references Handreck, K.A. and N.D. Black (1999). Growing Media for Ornamental Plants and Turf. University of New South Wales Press, Sydney, Australia. Hoitink, H.A.J. and P.C. Fahy (1986). Basis for the control of soilborne plant pathogens with composts. Annual Review of Phytopathology, 24: Standards Australia (2002). AS 3743 Potting mixes. Standards Association of Australia, Homebush, NSW, Australia. Standards Australia (2002). AS 4419 Soils for landscaping and garden use. Standards Australia, Homebush, NSW. Acknowledgement The authors would like to extend a special thankyou to members of the peer review committee for critically evaluating this document: Dr Trevor Gibson, NSW Agriculture; Dr Kevin Wilkinson, Agriculture Victoria; Mr Darren Bragg, Resource NSW; Mr Garry Kimble, Quality Assurance Services; Dr Martin Line, University of Tasmania; Mr Chris Rochfort, EC Sustainable Environment Consultants and Dr Pam Pittaway, University of Southern Queensland. Produced by: Recycled Organics Unit PO Box 6267 The University of New South Wales Sydney Australia 1466 Online contact details: ROU Internet Angus Campbell Whilst all care is taken in the preparation of this Information Sheet, the information provided is essentially general in nature and the Recycled Organics Unit disclaims all liability for any error, loss or other consequence which may arise from application of the information in any specific situation. Recycled Organics Unit

67 Information Sheet No Sample Management for Consistent Analysis of Products and Raw Materials Information Sheet No Third Edition Inside This Sheet Need for standard sample management procedures 2 Taking a representative sample of compost product Packaging and dispatch of the compost product samples 3 4 Definitions Receipt and processing of compost product samples at the laboratory Compost maturity testing Packaging and sample management for raw materials Important references Acknowledgement Need for standard sample management procedures Laboratory testing of recycled organics products is required to provide assurance that products meet minimum quality requirements, are fit for purpose, and/or are consistent with customer specifications. The purpose of this information sheet is to define standard sample management procedures from the point of dispatch at the manufacturing facility right through to the point of testing at a laboratory. Assessing compliance to an Australian or industry standard via off-site (independent) laboratory testing provides independent verification of the quality of the product(s) supplied to customers. Independent quality testing of products also provides an important management tool for organics processing facilities by providing a check on the reliability and performance of the process control system for product manufacture. However, non-representative sampling of product from windrows (for example), or poor sample handling and management by either the organics processing facility or the laboratory may produce unreliable testing results that do not accurately reflect the overall characteristics of the product available for sale. It is important to note that recycled organics products (eg. composts) are biologically active. The chemical, physical and biological properties of the product can change after sampling, if samples are not managed correctly. This means that standard procedures are required to ensure correct and consistent sampling and sample management. If these procedures are not followed consistently, laboratory test results will be unreliable. For example, if a 20 litre sample of composted soil conditioner is sampled from a compost windrow, and is left to stand for 2 weeks in a sealed plastic bag in a site office or laboratory, the properties of the product are likely to change. Plate 1. Finished batch of composted soil conditioner ready for off-site laboratory testing according to Australian Standard AS 4454 (2003). Recycled Organics Unit 2003 ISBN Information for organic resource recovery, management, research & development, quality systems and training