Rainstream storage, filtration

Transcription

1 Rainstream storage, filtration and re-use of rainwater Rainstream from Polypipe WMS offers a range of highly effective solutions for the storage, filtration and re-use of rainwater. All products have been developed to focus solely on the UK market and are manufactured to offer the most cost effective solution to maximising the re-use of rainwater in the UK. Polypipe WMS applies unrivalled technical knowledge and expertise to design and commission applications for domestic, commercial and public sector developments. Polypipe WMS are committed to designing solutions calculated to UK rainfall and weather patterns. We have a clear knowledge of the environmental issues and UK government legislation surrounding rainwater harvesting through our involvement with the UK Rainwater Harvesting Association and British Water. Why harvest rainwater? Population growth and rising consumption is increasing the demand for water Climate change is creating pressure to conserve water Legislation is enforcing the need to conserve water Higher water charges and water metering are predicted 56

2 Products and Solutions 2C Products and Solutions Rainstream Contents Page Climate change and water demand 2C 58 Legislation and standards 2C 59 Rainstream the complete system 2C Rainstream Commercial 2C Rainstream Home XL 2C Tanks, filters and disinfectants 2C Additional and bespoke options 2C Pumps and controls 2C 70 Education 2C 71 Case Studies 2C

3 Climate change and water demand With average UK annual temperatures predicted to rise by up to 3.5 C over the next 70 years, climate change is already driving the need for innovative solutions to the management of rainfall and surface water. Changing rainfall patterns are likely to lead to wetter winters and drier summers, sea levels are expected to rise and extreme weather events look set to become far more commonplace. The summer of 2007 gave a clear indication of the consequences that these sorts of changes can bring when 57,000 UK homes were affected by surface water flooding which caused 3 billion of damage. With so many homes and commercial developments, plus much of our major road network in the UK currently facing a real risk of surface water flooding, now is the time to take action. Average rainfall increase 2008 figures The average person in England and Wales now uses 150 litres of water every day - almost 50% more than 25 years ago. Washing and toilet flushing account for much of this figure, with drinking, cooking, car washing and garden watering also playing large parts. Yet while continental countries such as Italy and Spain enjoy water supply capacities of on average 2,785 m³ per person, per year, England and Wales has a surprisingly low capacity of just 1,334 m³ per person. The high population densities in areas such as South East England mean that there is even less water available to each person in these regions. Rainwater re-use solutions offer a way to address this increasingly important issue by collecting and recycling rainwater, rather than simply allowing it to drain away. This not only reduces the demand for mains water for toilet flushing, laundry, vehicle washing and irrigation purposes, but also eases the potential for flooding which can be created when rainwater deposited by extreme storms is simply left to run to ground. Normal range Above average Substantially above average Very wet 20% 80% 2,600 Litres per day On average a non-domestic building uses approximately 2,600 litres a day, with up to 80% of the water delivered for non-potable applications such as toilet flushing. Much of this could be provided by harvested rainwater. 58

4 Legislation and standards Products and Solutions 2C Growing public awareness of water issues has helped create a large body of legislation and standards. Polypipe WMS is committed to helping customers understand these issues and comply with all the necessary requirements. As an essential component of effective SUDS solutions, rainwater re-use plays a central part in this process and can help meet the requirements of PPS25, Building Regulations Part H, the Code for Sustainable Homes and many other recognised standards. Rainwater re-use can also help achieve the aims of the Wildlife and Countryside Link s Blueprint for Water document, which offers a timetable for achieving a sustainable standard of water by It complements the EU s Water Framework Directive by aiming to reduce consumption by 20% - something which rainwater re-use can often achieve. Future water strategy This document explains how the Government wants the water industry to operate by the year It focuses on such issues as reducing water consumption from 150 litres per day to 130 litres per day and improving water supply by building more reservoirs and issuing fewer abstraction licenses. The quality of water in the natural environment is also covered, as is the use of SUDS measures to improve surface water drainage, the wider use of water metering in water stressed areas and the need for better planning to reduce the risk of flooding from rivers and rising sea levels. For more information visit Making better use of a valuable resource Planning policy statement (PPS25) This sets out Government policy on flood risks associated with development. It aims to make flooding a central consideration of the planning process, so that only appropriate development is undertaken in areas at risk, with that risk limited as far as possible. For more information visit The Code for Sustainable Homes The Code is used to rate the environmental performance of new homes in England, Wales and Northern Ireland and compliance is mandatory. To achieve target ratings set for 2016, developers must adopt measures such as rainwater re-use that will significantly cut water consumption. For more information visit: BS: 8515 This BSI rainwater harvesting code of practice gives guidance on design, installation, testing and maintenance of systems for non-potable applications. For more information visit BREEAM The Building Research Establishment Environmental Assessment Method (BREEAM) is now recognised as the standard measure of sustainable building design. It addresses environmental and sustainability issues and enables developers to prove the environmental credentials of their buildings to planners and clients. For more information visit 59

5 Rainstream the complete system The flexible nature of Polypipe s approach to rainwater re-use means that no two Rainstream Systems are ever the same, as each one is designed to meet the specific requirements of an individual application. A number of elements are common to many types of system however and the operating principles are largely standard throughout. Bespoke solutions for off-site construction The Polypipe WMS team benefits from access to Polypipe Civils own in-house fabrications department. Using our own products and expertise, Polypipe Civils are able to design and fabricate any solution to meet specific site constraints. Solutions such as bespoke leaf filters are delivered to site pre-fabricated, reducing installation times and labour costs on-site Rainwater falling onto roofs, roads and paved areas can be collected by a variety of measures which include guttering, channel drainage and specialised roof drain systems. Pre-tank filtration then removes any larger pieces of debris such as leaves, before the collected water passes to the storage tank. The storage vessel is typically a large tank which can sometimes be included within a building, surface mounted externally or buried below the surface of the site. Captured water is re-distributed through a second stage filtration and pump assembly. 60

6 Water Management Solutions 2C A sophisticated control unit monitors water levels in various parts of the system and matches these to the 8 Water is supplied on demand to a number of outlets around the property and can be used for many different water demand at the outlets. purposes including flushing toilets, watering gardens 6 7 Third stage in-line filtration to remove finer particles of debris before use. An optional ultraviolet disinfection process can be used to kill off bacteria and improve the quality of 9 or cleaning vehicles. A back flow prevention device stops a backward flow of contaminated water from the sewer and acts as a rodent barrier. the collected water. 10 Outlet to the sewer, soakaway or attenuation. 61

7 Rainstream commercial Large-scale solutions from Polypipe WMS have been installed on a wide variety of projects, from Ministry of Defence sites through to retail developments. Our team of fully-qualified designers and engineers have the technical pedigree and manufacturing capability to design solutions to meet any site requirements. Key benefits of Rainstream Tank sizes from 1,500 to 300,000 litres (smaller tanks are available if required) Leaf filter within bespoke chambers to suit specific project Full technical design and support Complete range of additional items such as duty standby and booster systems Mains water back-up Helps reduce your carbon footprint by lowering the volume of water from local treatment works Tank system supplied with filters, pumps, valves, component set and factory fitted inlet, calmed inlet and outlet connections Bespoke design solutions offered for any site constraint Robust GRP tank construction Filter uses first flush principle (see page 69) Manifold system available for multiple dwellings Water filtered to 110 microns Ability to increase water capture by using specialist filters such as Storm-X4 Assessment and advice Polypipe WMS offers a wide range of advice and support to help understand the solutions available for the effective capture, storage, filtration and re-use of rainwater. Services include - assessment, tank sizing calculations, technical detail and system schematics. Together these services ensure that customers receive the most suitable and effective rainwater re-use system for their particular application. 62

8 Gravity (indirect systems) Water Management Solutions 2C 1 Control box Header tank 3 Raised valve chamber with AB air gap 4 Mains water feed Re-used rainwater Pressure (direct systems) 1 Control unit - with AA air gap and break tank 2 Mains water feed 3 Re-used rainwater

9 Rainstream Home XL Polypipe WMS are able to offer a specialist rainwater harvesting solutions for domestic applications. The Rainstream Home XL system is ideal for both individual, on-plot rainwater harvesting solutions and can also be used as a manifold system to feed multiple dwellings. Where deeper burial depths are required (often characteristics of communal storage systems) this structured wall tank is capable of withstanding water pressure up to 6m burial depths or 0.6 bar. 64

10 Water Management Solutions 2C 1 Captured rainwater 3 Control panel 5 Re-used rainwater 2 Leaf filter 6 Overflow discharged through 4 No need for a concrete surround an attenuation system (or by infiltration) The Rainstream Home XL System The structured wall design of Rainstream Home XL has created a system that is unique in its ability to withstand a high water table. The key benefit of Rainstream Home XL is that it will never need a concrete surround in non-loaded applications, even in cases of a high water table. All that is needed is a concrete base which the tanks are strapped to. It provides a simple solution to the complex problem of rising water tables and changing weather patterns. As most systems are installed during the summer months, when water tables are at their lowest, the resulting winter rising water table is often not taken into account. Some systems are not designed to be installed within the water table and are unable to withstand the hydrostatic pressures, resulting in their collapse. Rainstream Home XL has been designed by Civil Engineers to withstand these hydrostatic pressures. Further testing has taken place proving the tank s capability to withstand water pressure at a burial depth of up to 6 metres or 0.6 bar, far beyond the pressures the tank is likely to face. The range of tank sizes offered by Polypipe WMS has been researched and designed to meet the exact requirements of the UK market, based on research into the national average household water use and the most up-to-date MET office data. Rainstream Home XL tanks allow the homeowner to meet their exact requirements and therefore provide the most cost-effective and efficient solution in the market, without the need to over-specify and incur disproportionate purchasing and installation costs. If increased capacity is needed, Rainstream Home XL offers a wide range of tank sizes to ensure rainwater collection is maximised effectively. Polypipe WMS offer both gravity-fed and pressurised systems. Manifold System for Multiple Dwellings A manifold system can be a highly effective and economical way of capturing rainwater from multiple properties. Please see page 69 for more information. 65

11 Tanks Normal duty up to 1m Heavy duty up to 2m Below ground solutions Rainstream tanks for below ground installation represent a practical and effective way to accommodate a large part of the rainwater re-use system and preserve the appearance of the site. Below ground installation protects the captured water from fluctuating temperatures and exposure to sunlight. Manufactured from GRP they are available in capacities that range from 1, ,000 litres. A variety of duty types are offered which can be buried between 1 4 metres from the surface to accommodate different site conditions. Super heavy duty up to 4m Above ground solutions Rainstream above ground sectional tanks are also available in capacities from 2,000 litres upwards. Manufactured from tough pre-insulated GRP panels they offer exceptional design flexibility and allow tanks of different sizes and shapes to be created to suit individual projects. These tanks are suitable for installation inside buildings once they have been constructed. Designed with a flat bottom for installation onto a hard-standing surface, Rainstream above ground one piece tanks are manufactured from rugged Glass-Reinforced Plastic (GRP). Their one-piece construction provides maximum strength and robustness and they are available with capacities ranging from 6,000 36,000 litres. 66

12 Filters and disinfectant Water Management Solutions 2C Although captured water quality can be compromised by debris picked up from the collection surface, it is still suitable for non-potable purposes provided it is processed by a system that has been correctly designed and installed. The use of high quality components and proven system design principles allows Polypipe WMS Rainstream systems to meet the requirements of BS8515. Disinfection UV radiation DNA The filtration process Water arriving at the filter is distributed evenly across the full width of the filter cascade. The cascade pre-cleans the water by diverting the larger particles of debris away to the sewer. Water then flows over the secondary filter sieve where a special mesh allows the remaining dirt particles to fall away to the sewer. Cleaned water flows into the storage tank ready for re-use. Direction of flow The disinfection process The captured water passes through a disinfection unit where it is exposed to a high level of ultraviolet radiation. This alters the nucleic acid (DNA) of any viruses, bacteria, moulds or parasites and prevents them from reproducing, leaving the water chemically unaltered while improving Filtration the quality. This is a particularly important process where those people more susceptible to infection may come into contact with the recycled water particularly the very young or the elderly. If this is likely, or if the water may be used in an aerosol form e.g. a vehicle wash-down area, Polypipe WMS recommends that a risk assessment is carried out to ascertain the need for ultraviolet disinfection. The Rainstream range offers a wide variety of filtration options, ranging from basic leaf filters to systems capable of removing metals, oil, chemicals and even bacteria such as legionella. Polypipe WMS experts are on hand to help you choose the most appropriate option for your application. 67

13 Additional options Polypipe WMS is committed to finding the right solutions for specific sites and is able to offer a range of additional options to complement the standard Rainstream system, for both residential and commercial applications. Header tanks Polypipe WMS can supply a range of header tanks to suit each application. Header tanks are used in conjunction with a gravity system and can either be connected directly to the Rainstream tank or connected to a booster system. Please contact the Technical Team on for further details. Booster system A booster system consists of a GRP storage tank and booster pump to deliver non-potable water under pressure, around the building, over a large distance or to a high head. The tanks are supplied as either sectional or one-piece GRP tanks that connect directly to the Rainstream underground tank. Sited within the building envelope (typically in a plant room) the tank holds sufficient capacity to ensure a constant supply of non-potable water throughout the day. The booster pumps are controlled via the supplied control panel and run in sequence to increase the life of the system and give back-up in the unlikely event of one pump failure. A booster system is often required within a large scale development, typically large office blocks, retail premises or schools. Rainstream Advanced Control Unit (ACU) Polypipe s Rainstream ACU is the latest development in non-domestic rainwater re-use. From designer to user the Rainstream ACU offers a simple and effective solution for the control of rainwater distribution. Featuring, in a single unit, intelligent pump control combined with integral break tank and mains water top up, the Rainstream ACU saves space in the plant room, a separate break tank and booster set are not required and it minimises the volume of mains water required in dry periods. Duty standby sets Rainstream is supplied as standard with one pump. However, in high demand applications, a duty standby set may be required. The duty standby sets from Polypipe WMS are positioned within the Rainstream underground storage tanks and are typically used where there is high demand within the building. A key benefit of the duty standby set is the inclusion of two pumps which work in sequence. This increases the life of the system and gives back-up in the unlikely event of one pump failure. Available as either pressurised or gravity systems. Building management system (BMS) connections The Rainstream control panel allows easy connection to the BMS through a volt-free connection. This allows the BMS to monitor the Rainstream system and provide an alert in the event of a system fault. Storm-X4 Storm-X4 is a stormwater treatment system for roof and surface water run-off. Storm-X4 is capable of cleaning surface water run-off from roofs, car parks and the most polluted roads, even in heavily trafficked areas. Storm-X4 has been designed to remove heavy particles, silt and nutrients and heavy metals such as copper, zinc and cadmium from the surface water to provide an environmentally sound solution which benefits the natural watercourse and increases biodiversity. 68

14 Bespoke options Water Management Solutions 2C Low invert drop filters In situations where the existing drain run dictates the invert level, low invert drop leaf filters may need to be considered. Polypipe WMS is unique in its ability to offer patented bespoke low invert drop leaf filters within a prefabricated chamber. Designed to exact customer specifications the low invert drop leaf filters and chambers allow a minimum invert drop of only 66mm, enabling connection to an existing drain run. Manifold system A manifold system can be a highly effective and economical way of capturing rainwater from multiple properties to be re-used for non-potable applications. Using one large GRP tank to serve multiple properties, the water is fed to each individual property on demand. Manifold systems capture rain from multiple roofs, increasing the catchment area and reducing the installation costs associated with multiple tank systems. Site specific filter designs off-site construction All leaf filters are installed within a prefabricated chamber to exact customer requirements unless otherwise specified. Any roof size can be catered for and we are able to create chambers up to 2100mm in diameter, resulting in a truly efficient and cost-effective solution. A manifold system is ideal for installation within: Large developments, where single installations are unviable Housing Association properties Multiple tenant properties Rural developments with communal services Integration with full SUDS solution Polypipe manufactures a range of sustainable drainage solutions, from modular cells to pipes, for use as soakaway or attenuation solutions. Polypipe WMS offers a fully considered and holistic approach to SUDS, focusing on system integration. 69

15 Pumps and controls A variety of accurate and reliable pump and control options allow Rainstream systems to offer a high degree of flexibility. Standard systems The standard Rainstream control set includes a single pump assembly, inline filtration unit and a control module compatible with both gravity and pressure operated systems. In a gravity system the control unit constantly monitors the water level in the header tank, automatically drawing in more water from the main storage tank if required. The storage tank is also monitored so that fresh mains water can be imported if needed. This ensures that the header tank always contains the minimum water volume required for safe operation. For a pressure system the control unit automatically detects any demand for water and delivers a pressurised flow to all outlets. If the storage tank volume drops below the minimum, the control unit draws in sufficient mains water to ensure that the required output level is maintained. Duty standby systems Rainstream duty standby component sets include a double pump assembly, in-line filtration and a control module suitable for both gravity and pressure-fed systems. This maintains efficiency, increases operating life and ensures continuity of supply even in the unlikely event of one pump failing. Advanced systems Rainstream advanced pressure-fed systems provide the most reliable control over the water supply and feature a duty standby function which delivers a constant supply of water to all outlets. The storage tank level is constantly monitored and if necessary the system will switch to using fresh water to maintain the supply at the outlets. Gravity System Header tank level sensor Pressure System Pressure sensor Control Unit Mains Water Inlet control Storage Tank Level sensor Pump control 70

16 Water Management Solutions 2C Education Terms such as climate change, sustainability and global warming all now make the news headlines on a regular basis and many people take an interest in these issues. Polypipe WMS believes that it is essential we encourage future generations to become more aware and actively involved. With this in mind the company has developed a suite of teaching aids which parents and teachers can use to engage children in water usage and other environmental issues. Polypipe Rainstream Classroom Polypipe Rainstream Classroom is designed for children between the ages of 4 to 11 and offers a range of activities which encourage them to interact with their local environment. Created to help them discover the answers to the questions they have, Rainstream Classroom introduces the children to topics such as rainwater recycling and includes access to a source of online content and a moving water activity pack. Polypipe Rainstream Monitor Installing a Polypipe Rainstream Monitor pack encourages users to monitor the water usage in their building. Primarily intended for use with Rainstream Classroom to monitor water use within schools, children and teachers will have the opportunity to collect water usage data and understand how water is used in their school. Polypipe Rainstream Monitor is also offered in other designs, including the option to customise (e.g. to match a school crest or company name) allowing companies to demonstrate a proactive awareness of water use issues to staff and visitors. Terry our wise rainwater harvesting owl is used at our Rainstream Classroom sessions to help talk about water conservation with the children. 71

17 Case studies Polypipe WMS supplies 100,000 litre rainwater harvesting solution for Bristol PFI College A bespoke 100,000 litre Rainstream tank and leaf filter were supplied by the Polypipe WMS team to Brislington Enterprise College in Bristol as part of the Building Schools for the Future PFI. Installed to cope with rainwater from the school s 5,000 square metre roof area, the tank will store and filter rainwater before it is used for toilet flushing within the new development, providing a sustainable method of reusing rainwater. Working alongside contractor Skanska, several alterations were made to the standard Rainstream system to produce one of the largest tanks of its kind, including the supply of additional inlets on-site to suit the project requirements. Rainstream rainwater harvesting tanks reduce mains water consumption, providing increased cost savings on water bills. It is calculated that the Rainstream system installed at Brislington Enterprise College will save the Local Authority over 10,400 per annum. The site of the new college building is on sandstone rock, which enabled the tank to be installed without the need for temporary support. The tank itself was installed in a six metre deep hole and placed into position using an 80-tonne crane to cope with the tank s 11m x 3.3m dimensions. Polypipe WMS undertakes largest rainwater harvesting contract with Ministry of Defence The Polypipe WMS team were approached by the Ministry of Defence to supply a rainwater harvesting solution for the largest rainwater harvesting contract ever signed in the UK. Working in close partnership with the main contractor, Aspire Defence, Polypipe WMS will supply 150 of its Rainstream rainwater harvesting tanks over the next seven years as part of a redevelopment of various sites across the UK. Over 42,000 litres of capacity have been installed on the site at Tidworth, which would save the Ministry of Defence approximately 1,500 annually through the reduction in mains water consumption. Polypipe WMS redesigned the original Rainstream system to fulfil the requirements of Aspire Defence. These modifications included a filter which was redesigned to reduce invert loss on the existing drain run allowing for connection with a shallow main drain. This filter was delivered to site pre-fabricated within a chamber, bringing increased time savings to Aspire. The flexibility of the Rainstream system was an important factor for Aspire. 72

18 Water Management Solutions 2C Earthship project The Polypipe WMS team donated a full rainwater harvesting solution for the recently opened Brighton Earthship Low Carbon project. Since being installed on the project in July 2003, the four Rainstream Rainwater Harvesting tanks, each with a 20,000 litre capacity, have harvested over 50,000 litres of rainwater per year, giving a total mains water saving of over 150,000 litres. As an off-grid building, materials with low embodied carbon were used in the construction of the Earthship, with the thermal mass of the walls controlling the heating and cooling of the building. Through the use of the Rainstream rainwater harvesting system the Earthship project and Low Carbon Trust received a commendation from the Environment Agency at the 2007 Water Efficiency Awards, in the Inspiring Change and Construction & Renovation categories. Revolutionary development uses Polypipe Rainstream Seven Rainstream rainwater harvesting systems from Polypipe have been installed in a ground breaking development in the heart of the mining community in County Durham. The Close, in Houghton-le-Spring is a series of seven detached homes on a former brownfield site, where abandoned farm buildings were used to store machinery. This sustainable residential scheme is the brainchild of Spring Oak Developments Ltd, a private developer at the cutting edge of sustainable housing in the North East. Director, Bill King has a vision for the properties to defy the conventional build for this part of the country and so incorporated the most up to date and innovative sustainable systems and features. He used timber frame for the buildings envelopes, Low E glass for the windows as well as solar thermal panels to minimise the need for supplementary heating systems. The Rainstream rainwater harvesting concept played a major role in his ambition for total eco-design. Rainstream runs rainwater recycling in Old Cantley home A housing development by R.J. Cadman of Scunthorpe at Old Cantley near Doncaster includes a four bedroomed home which is being built to the client s own specifications. Among the green features included in the design is a system to recycle all rainwater drained from the 311 square metres of roof area for re-use for toilet flushing, in the washing machine and, more unusually, in the dish washer. This was achieved through a specially designed collection and redistribution system centred round a 7,500 litres capacity Rainstream system. The Rainstream tank, manufactured in GRP that is totally resistant to corrosion, was buried in the rear garden of the house with only the plate-surface of the tubular conning tower at lawn level to provide ready access to the internal plumbing and electrics. The lightweight qualities of GRP proved invaluable and eliminated the need for heavy lifting machinery. When the Rainstream Gravity System is in operation, the drained rainwater will be piped from the gutters to the underground storage tank, filtered and then taken up to a header tank in the property s loft. 73