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Chapter two

waste Management

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Chapter two

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  1. CHAPTER -2 CHAPTER -2: WASTE MANAGEMENT Contents 2.1 Waste management principles 2.1.1 Waste management hierarchy 2.1.2 Integrated solid waste management systems (Life cycle based, generation based and management) 2.2 Products development from wastes 2.2.1 Ecology of various wastes 2.2.2 Composite products of solid wastes 2.3 E-technologies and their development 2.3.1 E-technologies for solid wastes 2.3.2 E-technologies for liquid wastes 2.3.3 E-technologies for air emissions

  2. 2.1 Waste management principles

  3. 2.2 Waste Management Hierarchy The waste management hierarchy is used as an over-riding principle in respect to waste management strategy and policy development. This hierarchy is widely accepted and used at an international level, and is represented in the figure below.

  4. Waste Avoidance & Reduction • As the first principle of the waste management hierarchy, a clear emphasis must be placed on determining how a waste stream can be avoided altogether, or at least substantially reduced. These principles are imbedded in the practice of cleaner production, with industries finding that waste avoidance through product substitution or process change can often translate into substantial economic benefits. • By clearly focusing on waste avoidance and reduction as opposed to end of pipe treatment and disposal technologies, the final ‘problem’ is reduced accordingly, as well as the associated costs.

  5. Re-use • The principle of reuse is one that is well applied in the developing country context. Reuse is re-utilisingwaste material without making substantial changes to its form. Repair goes hand in hand with reuse, revitalizing the utility value of the product through applying skills and labour. Reuse can also be applied to using a waste product for a new use. For example, making seedling pots from plastic bottles or liquid paperboard cartons. Reuse is a principle that tends to be overlooked as affluence and consumerism grows.

  6. Recycling • Recycling is a process that utilises waste materials and applies various technologies to change the material into useful feed stocks for industrial or manufacturing processes. Recycling is further down the hierarchy due to the higher costs involved in collection, transport and reprocessing. The recycling industry can sometimes be volatile, with market fluctuations creating uncertainty within the industry. Recycled materials are usually competing against virgin products, which are often relatively cheap. Virgin materials do not have the environmental costs of their product built into the price, making it difficult for recycled resources to compete. This is particularly the case for low value plastics and recycled paper. However, in many cases, recycling makes good environmental and economic sense.

  7. Recycling • Recycling is a process that utilises waste materials and applies various technologies to change the material into useful feed stocks for industrial or manufacturing processes. Recycling is further down the hierarchy due to the higher costs involved in collection, transport and reprocessing. The recycling industry can sometimes be volatile, with market fluctuations creating uncertainty within the industry. Recycled materials are usually competing against virgin products, which are often relatively cheap. Virgin materials do not have the environmental costs of their product built into the price, making it difficult for recycled resources to compete. This is particularly the case for low value plastics and recycled paper. However, in many cases, recycling makes good environmental and economic sense.

  8. T R E A T M E N T A N D S E C U R E D I S P O S A L This segment of the waste hierarchy is the one with the highest costs, and the highest environmental risks. There is a range of options put forward by various proponents for the following technologies: · Pre-treatment for waste stabilization · Incineration (sometimes incorporating waste to energy) · Sanitary landfilling Particularly landfilling and incineration options have environmental risks as well as high capital input requirements. For many communities the choice for final disposal is often based on the cost of establishing and operating these facilities. Internationally the waste management industry supports both technologies provided that both are operated to the highest environmental standards possible. This is achieved through employing best practice design, management and monitoring criteria. However, by applying all of the higher principles of waste management, the problem of residual waste disposal can be substantially minimized.

  9. Incineration

  10. 2.1.2 Integrated solid waste management systems Definition: Integrated Waste Management (IWM) systems combine waste streams, waste collection, treatment and disposal methods, with the objective of achieving environmental benefits, economic optimization and societal acceptability. This will lead to a practical waste management system for any specific region.

  11. Raw materials Processing and manufacturing Products Solid and hazardous wastes generated during the manufacturing process Waste generated by households and businesses Remaining mixed waste Food/yard waste Hazardous waste Plastic Glass Metal Paper To manufacturers for reuse or for recycling Hazardous waste management Compost Incinerator Landfill Fertilizer

  12. A Integrated Waste Management: Priorities for Dealing with Solid Waste First Priority Second Priority Last Priority Primary Pollution and Waste Prevention Secondary Pollution and Waste Prevention Waste Management Treat waste to reduce toxicity Change industrial process to eliminate use of harmful chemicals Reuse Repair Incinerate waste Use less of a harmful product Recycle Bury waste in landfills Reduce packaging and materials in products Compost Release waste into environment for dispersal or dilution Buy reusable and recyclable products Make products that last longer and are recyclable, reusable, or easy to repair Approaches in ISWM Life cycle based Generation based Management based

  13. Life cycle assessment • A process to analyze the materials, energy, emissions, and wastes of a product or service system, over the whole Life Cycle ‘from cradle to grave’, i.e. from raw • material mining to final disposal. Currently considered to consist of four stages: Goal Definition, Inventory Analysis, Life Cycle Impact Assessment and Life Cycle Interpretation. • Goal Definition and Scope • Stage at which the functional unit for comparison is defined (normally per equivalent use), as well as the study purpose, system boundaries, Life Cycle stages, unit processes and scope of the assessment. • b) Life Cycle Inventory • Process of accounting for all the inputs and outputs of Analysis the product system over the Life Cycle. Will result in a list of raw material and energy inputs, and of individual emissions to air, water and as solid waste. • c) Life Cycle Impact Assessment • Associates the inputs and outputs with particular environmental issues, e.g. ozone depletion, and converts the inventory of materials, energy, and emissions into representative indicators, e.g. an aggregate loading of ozone-depleting chemicals. • d) Life Cycle Interpretation • Evaluation of the significance of the inputs, outputs, and indicators of the system Life Cycle. This stage is the least well accepted or defined.

  14. 2.2 Products development from wastes • Energy from Waste • Waste to Energy is a common solution for numerous environmental challenges • Renewable energy • Safe and economic waste disposal • Reduce emission of greenhouse gas • CO2 Emission Reduction • Emission Control • Landfill Environmental Impact Reduction ENVIRONMENT • Cost Reduction • Profit Product • New Industry ECONOMY • Energy Recovery • Alternative Energy Potential • Improved Energy Efficiency ENERGY

  15. Electricity Smokestack Turbine Steam Crane Generator Wet scrubber Furnace Boiler Electrostatic precipitator Water added Waste pit Bottom ash Dirty water Conveyor Fly ash a waste-to-energy incinerator with pollution controls. It burns mixed solid wastes and recovers some of the energy to produce steam used for heating or producing electricity. Ash for treatment, disposal in landfill, or use as landfill cover

  16. Composting Is the controlled biological decomposition of organic solid waste under aerobic (in the presence of oxygen) conditions. Organic waste material are transformed in to soil amendments as humus or mulch.

  17. Composting COMPOSTING NEEDS • Air • Water • Food (Organic materials) • * Browns categories • * Greens categories

  18. Composting WHAT TO COMPOST • Grass/lawn clipping • Hay • Kitchen wastes • Leaves • Manure • Straw • Weeds and other garden wastes • Wood chips and sawdust

  19. 2.3 E-technologies and their development

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