temperature and contains chemicals such as acetic acid, acetone, and methanol; and (3)a char consisting of almost pure carbon plus any inert material that may have entered the process. For cellulose C6H1oOs) the following expression has been suggested as being representative of the pyrolysis reaction 3C6H1oO5-8H20+ C6H8O+ 2C0+ 2CO2+ CH4 + H3+7C (14-15) In Eq.(14-15), the liquid tar and/or oil compounds normally obtained are represented by the expression C6HgO Gasification. The gasification process involves partial combustion of a carbonaceous fuel so as to generate a combustible fuel gas rich in carbon monoxide, hydrogen, and some saturated hydrocarbons, principally methane. The combustible fuel gas can then be combusted in an internal combustion engine or boiler. When a gasifier is operated at atmospheric pressure with air as the oxidant, the end m== dioxide( coz) char containing yrolytic oil Other Chemical Transformation Processes. In addition to the various combustion, pyrolysis, and gasification processes under investigation and/or construction, a variety of other public and proprietary processes are being developed and evaluated for the transformation of solid waste. The hydrolytic conversion of cellulose to glucose, followed by the fermentation of glucose to ethyl alcohol, is an example of such a process Biological Transformations The biological transformations of the organic fraction of MSw may be used to reduce the volume and conditioner; and to produce methane. The principal organisms involved in the biological transformations of organic wastes arc bacteria, fungi, yeasts, and actinomycetes. These availability of oxygen The romplished either aerobically or anaerobically, depending on the principal differences between the aerobic and anaerobic conversion eactions are the nature of the end products and the fact oxygen must be provided to accomplish the aerobic conversion. Biological processes that have been used for the conversion of the organic fraction of MSw include aerobic composting, anaerobic digestion, and high-solids anaerobic digestion Aerobic Composting. Left unattended, the organic fraction of MSw will undergo biologica decomposition. The extent and the period of time over which the decomposition occurs will depend on the nature of the waste the moisture content, the available nutrients, and other environmental factors Under controlled a stable organic residue known as compost in a reasonably short period of time(four to six weeks) Composting the organic fraction of MSW under aerobic conditions can be represented by the following equation Organic matter +Oz+ nutrients- new cells resistant organic matter CO2+ H2O+ NH3+ SO42-+heat (14-16) In Eq. (14-16), the principal end products are new cells, resistant organic matter; carbon dioxide water, ammonia, and sulfate. Compost is the resistant organic matter that remains. The resistant organic matter usually contains a high percentage of lignin, which is difficult to convert biologically in a relatively short time. Lignin, found most commonly in newsprint, is the organic polymer that holds together the cellulose fibers in trees and certain plants Anaerobic Digestion. The biodegradable portion of the organic fraction of msW can be convened biologically under anaerobic conditions to a gas containing carbon dioxide and methane( CH4). Thi conversion can be represented by the following equation Organic matter +H2O +nutrients- new cells resistant organic matter CO2+ CH4+ NH3 +h,s+ heat 14-17 Thus, the principal end products are carbon dioxide, methane, ammonia, hydrogen sulfide, and resistant organic matter. In most anaerobic conversion processes carbon dioxide and methane constitute over 99 percent of the total gas produced. The resistant organic matter(or digested sludge) must be dewatered before it can be disposed of by land spreading or landfilling. Dewatered sludge is often composted aerobically to stabilize it further before application. Other Biological Transformation Processes. In addition to the aerobic composting and anaerobic digestion processes, a variety of other public and proprietary processes are being developed and evaluated for the biological transformation of solid waste Importance of waste Transformations in Solid Waste Management Typically, physical, chemical, and biological transformations are used (1)to improve the efficiency of 14-814-8 temperature and contains chemicals such as acetic acid, acetone, and methanol; and (3) a char consisting of almost pure carbon plus any inert material that may have entered the process. For cellulose C6H10O5) the following expression has been suggested as being representative of the pyrolysis reaction: 3C6H10O5 → 8H2O + C6H8O + 2CO + 2CO2 + CH4 + H2 + 7C (14- 15) In Eq. (14- 15), the liquid tar and/or oil compounds normally obtained are represented by the expression C6H8O. Gasification. The gasification process involves partial combustion of a carbonaceous fuel so as to generate a combustible fuel gas rich in carbon monoxide, hydrogen, and some saturated hydrocarbons, principally methane. The combustible fuel gas can then be combusted in an internal combustion engine or boiler. When a gasifier is operated at atmospheric pressure with air as the oxidant, the end products of the gasification process are (1) a low-Btu gas typically containing carbon dioxide (CO2), carbon monoxide (CO), hydrogen (H2), methane (CH4), and nitrogen (N2); (2) a char containing carbon and the inerts originally in the fuel, and (3) condensible liquids resembling pyrolytic oil. Other Chemical Transformation Processes. In addition to the various combustion, pyrolysis, and gasification processes under investigation and/or construction, a variety of other public and proprietary processes are being developed and evaluated for the transformation of solid waste. The hydrolytic conversion of cellulose to glucose, followed by the fermentation of glucose to ethyl alcohol, is an example of such a process . Biological Transformations The biological transformations of the organic fraction of MSW may be used to reduce the volume and weight of the material; to produce compost, a humus-like material that can be used as a soil conditioner; and to produce methane. The principal organisms involved in the biological transformations of organic wastes arc bacteria, fungi, yeasts, and actinomycetes. These transformations may be accomplished either aerobically or anaerobically, depending on the availability of oxygen. The principal differences between the aerobic and anaerobic conversion reactions are the nature of the end products and the fact oxygen must be provided to accomplish the aerobic conversion. Biological processes that have been used for the conversion of the organic fraction of MSW include aerobic composting, anaerobic digestion, and high-solids anaerobic digestion. Aerobic Composting. Left unattended, the organic fraction of MSW will undergo biological decomposition. The extent and the period of time over which the decomposition occurs will depend on the nature of the waste, the moisture content, the available nutrients, and other environmental factors. Under controlled a stable organic residue known as compost in a reasonably short period of time (four to six weeks). Composting the organic fraction of MSW under aerobic conditions can be represented by the following equation: Organic matter + O2 + nutrients → new cells + resistant organic matter + CO2 + H2O + NH3 + SO4 2- + heat (14- 16) In Eq. (14- 16), the principal end products are new cells, resistant organic matter; carbon dioxide, water, ammonia, and sulfate. Compost is the resistant organic matter that remains. The resistant organic matter usually contains a high percentage of lignin, which is difficult to convert biologically in a relatively short time. Lignin, found most commonly in newsprint, is the organic polymer that holds together the cellulose fibers in trees and certain plants. Anaerobic Digestion. The biodegradable portion of the organic fraction of MSW can be convened biologically under anaerobic conditions to a gas containing carbon dioxide and methane (CH4). This conversion can be represented by the following equation: Organic matter + H2O + nutrients → new cells + resistant organic matter + CO2 + CH4 + NH3 +H2S + heat (14- 17) Thus, the principal end products are carbon dioxide, methane, ammonia, hydrogen sulfide, and resistant organic matter. In most anaerobic conversion processes carbon dioxide and methane constitute over 99 percent of the total gas produced. The resistant organic matter (or digested sludge) must be dewatered before it can be disposed of by land spreading or landfilling. Dewatered sludge is often composted aerobically to stabilize it further before application. Other Biological Transformation Processes. In addition to the aerobic composting and anaerobic digestion processes, a variety of other public and proprietary processes are being developed and evaluated for the biological transformation of solid waste. Importance of Waste Transformations in Solid Waste Management Typically, physical, chemical, and biological transformations are used (1) to improve the efficiency of