Waste to energy

starch, and other compostable plastics biodegraded in an industrial compost and an in-vessel industrial compost (Greene 2007a). 

The use of green yard waste compost on farmland can lead to a positive environmental impact with lower water usage, lower fertilizer usage, lower herbicide usage, and sequestration. Life cycle impact assessments of environmental concerns from production and application of composted products provide a net positive environmental impact. The use of composting process and products provides a reduction in GHG, human toxicity potential, ecotoxicity potential, and eutrophication potential due to lower use of fertilizers, herbicides, water, and electricity (LCA for Windrow Compost 2006). 

Solid waste can be burned to create energy in waste-to-energy facilities. The carbon sources in plastic can be a fuel source for several types of waste-to-energy processes. Four types of waste-to-energy facilities can use the plastic waste as a fuel in the combustion chamber. The types of waste-to-energy municipal solid waste (MSW) combustion include the following  

The US EPA provides a website for guidelines for generating electricity from MSW (EPA 2010). The MSW is unloaded at the waste-to-energy facility. Metals, glass, and other recyclables are separated out. The remaining burnable waste is fed into a combustion chamber and burned. The released heat produces steam that turns a steam turbine and generates electricity. 

The United States has approximately 87 MSW-fired power generation plants, generating approximately 2500 MW, or about 0.3% of total national power generation. The burning of MSW can create air emissions of 1671 kg of C02/MWh, 0.54 kg of S02/MWh, and 3.0 kg of nitrogen oxides/MWh. Emission and effluents can be minimized with efficient design (Fodor and Klemes 2012). 

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J. Barton, Evaluation of Trommels for Waste to Energy Plants, Phase I, National Center for Resource Recovery, Washington, D.C., 1982. 

Refuse-Derived Fuel. Many processing faciUties divert a portion of the material that is not recovered for recycling to waste-to-energy plants, also referred to as resource recovery faciUties, where the material is employed as fuel. The processes involved in the production of refuse-derived fuel (RDF) are outlined in Figure 4 (23). Nine different RDFs have been defined, as Hsted in Table 3 (24). There are several ways to prepare RDF-3, which is perhaps the most popular form and is the feed used in the preparation of densified refuse-derived fuel (d-RDF). AH forms of RDF are part of the broader set of waste-derived fuels (WDF), which includes various waste biomass, eg, from silvaculture or agriculture (see Fuels frombiomass Fuels fromwaste). 

The extent to which each technology is poised to advance is described in separate discussions of photovoltaics, solar-thermal power, and wind, biomass, waste-to-energy, geothermal, hydropower, and wave energy. 

The conventional means of disposiag of MSW is hy landfilling. About 75% of MSW is disposed of ia this manner, with the balance handled by converting waste to energy (about 15%) and recycling. However, because landfills are becoming a less acceptable solution, alternative means of disposiag MSW have been advanced (Fig. 6). 

Fig. 6. An iategrated approach to the management of municipal soHd waste (MSW), advocated by the U.S. EPA, that links source segregation, recycling, waste-to-energy (WTE), and landfilling ia a single system. Source segregation refers to the separation of compostable and recyclable components from the balance of the trash at the poiat where MSW is collected. In source reduction (not shown), another action to reduce waste to landfills, changes are made ia...

Resource Recovery Act, 1970 The Solid Waste Disposal Act of 1965 was amended by Public Law 95-512, the Resources Recovery Ac4 of 1970. This act directed that the emphasis of the national solid-waste-management program should be shitted from disposal as its pri-maiy objective to that of recycling and reuse of recoverable materials in sohd wastes or the conversion of wastes to energy. 

The purpose of this subsection is to introduce the reader to the tech-niqiies and methods used to recover materials, conversion products, and energy from solid wastes. Topics to be considered include (I) processing techniques for solid waste, (2) processing techniques for hazardous wastes, (3) materials-recoveiy systems, (4) recovery of biological conversion products, (5) therm processes, and (6) waste-to-energy systems. 

FIG. 25-66 Waste -to-energy price index. National index, September 1994, 57.49/ton. Data from Solid Waste Digest, -ool. 4, no. 9, Sept. 1994. Fuhlished hy Chatiwell Information Publishers, Alexandria, VA. )... 

Meridian Corporation. (1986). Waste-to-Energy A Primer for Utility Decision-Makers. Golden, CO Western Area Power Administration. 

Energy Products of Idaho, Coeur d Alene, ID Waste-to-Energy Technology... 

Waste-heat and other special-purpose boilers Special designs provide boilers for waste heat and chemical recovery, waste-to-energy, and combined-cycle installations, pulverized-bed, and even biomass applications. 

E. Berenyi. "Overview of the Waste-to-Energy Industry." Chem. Eng. Prog, 82 (11), November 1986, 13. 

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