Waste Management for Food & Agriculture Industry Cleaner Production for Food industries

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1 Waste Management for Food & Agriculture Industry Cleaner Production for Food industries Thilina Gunawardhana Dept. of Chemical & Process Engineering University of Moratuwa

2 Cleaner Production In simple terms, it is management of the process effectively so that you minimize the waste generated, and manage the waste efficiently, by recycling, reusing or converting it to more useable option such as energy or value added products. Waste management in food industries is massively important to sustain the growth and economize the production.

3 Environmental Challenges Faced by the Food Industry Water availability Wastewater discharge Air emissions By-product disposal Utilization Chemical residues Solid waste disposal Food packaging materials

4 Life Cycle Analysis (LCA) The first step of waste management is to analysis the process and critically observe what happens to the material flow and waste generation. Life Cycle Analysis (LCA) can be used in this scenario.

7 LCA on Beer Production Facility - Example Raw material acquisition Beer production Bottle production Packaging and bottling Transportation/storage/distribution

9 Waste Management Strategies Different waste management strategies have been proposed by different environmental legislations and policies. The EU approach to waste management as follows, Waste prevention by improving product design Recycling and re-use including packaging waste, end-of-life vehicles, batteries, electrical and electronic waste Improving final disposal and monitoring.

10 Waste Management Strategies The other policies also adhere to a very similar methodology. They all can be summarized as below. Prevention Recycle Reuse Efficient Discharge

11 Food & Agricultural Waste Management Dairy industry Fermentation industry Brewery waste Winery waste Distillery waste Beverage industry Fruit and vegetable industry Meat and poultry Agricultural waste

12 Food Waste Treatment Methods Unlike other wastes, food industry wastes are very much difficult to handle and treat. It contains a lot of nutrients and favorable conditions especially for microorganisms, making it much susceptible for spoilage which could generate foul odor. Some of the treatment methods which are used in food waste handling are listed in the next slides.

14 Food Waste Treatment Methods Bioremediation, Anaerobic digestion, Aerobic digestion, Thermophilic anaerobic digestion, Sequencing batch reactor, Electrodialysis, wet oxidation, Pyrolysis, Incineration, Solid state fermentation Ozonation

15 Bioremediation Bioremediation technologies can be classified as in-situ or ex-situ. In-situ bioremediation treats the contaminated water or soil where it was found, whereas ex-situ bioremediation processes involve removing the contaminated soil or water to another location prior to treatment

16 Ex-situ bioremediation Slurry-phase bioremediation Contaminated soil is blended with water and other additives in a large tank to keep the microorganisms which are already present in the soil in contact with the soil contaminants. Nutrients and oxygen are added and conditions in the bioreactor are controlled to create the optimum environment for the microorganisms to degrade the contaminants. Bioreactors are used for this purpose.

17 Ex-situ bioremediation (Solid-phase bioremediation) Landfarming Contaminated sludge, soils or sediments are spread on fields and cultivated in the same way as a farmer might plough and fertilize agricultural land. The soil is periodically turned over to mix air into the waste

18 Ex-situ bioremediation (Solid-phase bioremediation) Composting Aerated static pile composting Compost is formed into piles and aerated with blowers or vacuum pumps Mechanically agitated in-vessel composting Compost is placed in a reactor vessel where it is mixed and aerated Windrow composting Compost is placed in long piles known as windrows and periodically mixed with means of mobile equipment

19 Ex-situ bioremediation (Solid-phase bioremediation) Biopiles Biopiles are a hybrid of landfarming and composting. Biopiles are similar to landfarms because they are both above-ground engineered systems consuming oxygen, generally from air, to stimulate the growth and reproduction of aerobic bacteria which, in turn, degrade the pollutants adsorbed to soil. While landfarms are aerated by tilling or plowing, biopiles are aerated most often by forcing air to move by injection or extraction through slotted or perforated piping placed throughout the pile

22 In-situ bioremediation Bioaugmentation The addition of organisms or enzymes to a material in order to remove any undesirable chemicals. Bioventing In the in-situ process, air is injected into contaminated soil at an optimal rate, increasing soil O2concentration and thereby stimulating the growth of indigenous aerobic bacteria.

23 In-situ bioremediation Biosparging Biosparging is used for treatment of groundwater contaminations. It involves the injection of air under pressure below the water table to increase groundwater oxygen concentrations and enhance the rate of biological degradation of contaminants by naturally occurring bacteria.

24 Thermal processes Incineration During the process, the waste is fed into the incinerator s combustion chamber where conversion of solids and liquids into gases occurs at C. The following types of incinerations are used in the industry. Circulating bed combustor Fluidized bed Infrared combustion Rotary kilns

25 Thermal processes Pyrolysis Pyrolysis transforms hazardous organic materials into gaseous components, small quantities of liquid and a solid residue (coke) containing fixed carbon and ash. Pyrolysis of organic materials produces combustible gases, including carbon monoxide, hydrogen and methane and other hydrocarbons. The typical types of pyrolysis units are, Rotary kiln Fluidized bed furnace Molten salt destruction

28 Thermal processes Gasification The gasification products are synthetic gas (called syngas, consisting mainly of carbon monoxide and hydrogen 85%, with smaller amounts of carbon dioxide and methane), other by-products including liquids and solid residues ash, or char The types of gasifiers in the industry are, Entrained flow gasifiers Fluidized bed gasifiers Fixed bed gasifiers

29 Other Thermal Processes Briquetting Activated carbon

30 Evaporation Evaporation is the vaporization of a liquid from a solution or slurry and is applicable to liquids, slurries and sludges. After the liquid portion of the waste is evaporated, the waste volume is considerably reduced. Vaporization Concentration Crystallization

31 Membrane Processes Membrane processing is a technique allowing for concentration and separation without resorting to thermal processes. Particles are separated on the basis of their molecular size and shape with the use of pressure and specially designed semi-permeable membranes Reverse osmosis (RO) Ultrafiltration (UF) Nanofiltration (NF) Microfiltration (MF) Gas separation (GS) Electrodialysis (ED) Pervaporation (PV)

33 Ozonation Ozone (O3) is one of the strongest oxidizing agents that is readily available. It is used to reduce color intensity, to eliminate organic waste, to reduce odor and reduce total organic carbon in water

35 Anaerobic Digestion Mesophilic digestion Mesophilic digestion is the most commonly used process for anaerobic digestion, in particular waste sludge treatment. The digester is heated to C and the feedstock usually remains in the digester for days. Gas production is less, larger digestion tanks are required

36 Anaerobic Digestion Thermophilic digestion Thermophilic digestion is less common and not as mature a technology as mesophilic digestion. The digester is heated to 55 C and residence time is typically days. Thermophilic systems result in higher methane production, faster throughput and better pathogen and virus kill, But they require more expensive technology, greater energy input and a higher degree of operation and monitoring

38 Aerobic Digestion Advantages over Anaerobic Digestion Volatile solids reduction is approximately equal to that obtained anaerobically Lower BOD concentrations in supernatant liquor Production of an odorless, humus-like, biologically stable end product Recovery of more of the basic fertilizer values in the sludge Operation is relatively easy Lower capital cost

39 Aerobic Digestion Disadvantages over Anaerobic Digestion A high power cost is associated with supplying the required oxygen A digested sludge is produced with poor mechanical dewatering characteristics The process is affected significantly by temperature, location and type of tank material. A useful by-product such as methane is not recovered

40 Types of Digesters Covered lagoon Covered lagoon digesters are the simplest anaerobic digester system. These systems typically consist of an anaerobic combined storage and treatment lagoon, an anaerobic lagoon cover, an evaporation pond for the digester effluent and a gas treatment and/or energy conversion system.

41 Types of Digesters Complete mix digesters The complete mix digester is a large, vertical poured concrete or steel circular container Nowadays, complete mix digester can treat organic wastes with total solid concentration of 3 to 10%. Complete mix digesters can be operated at either the mesophilic or thermophilic temperature

42 Types of Digesters Plug flow digesters Plug flow digesters are normally used where wastes are collected as solids (solids greater than 11%). Plug flow digesters are large tanks (often built into the ground) with an impermeable plastic cover. Although the contents are usually heated, they are not mixed because they move through the digester as a combined mass or a plug. Plug flow digesters have been used mostly with scraped dairy wastes, but a few were also applied to swine wastes

43 Other Methods Ultrasound irradiation Solid-state fermentation

44 By-Products from Food Waste Bioenergy Bioethanol Biogas Biodiesel Fertilizer Animal feed/dietary supplements Flavanols Other chemicals Combustible gases through gasification Biodegradable polymers

Technical overview and benefits

Technical overview and benefits Overview Terms used in anaerobic digestion Different types of digesters Benefits of anaerobic digestion Total Solids, Volatile Solids Total Solids (TS)= Dry matter content