supplementary fuel and rapid agitation of incoming waste. The main purpose of
incineration is the reduction in the volume of waste (>90%) that ultimately extends
the lifetime of the land disposal facility. The second purpose is the generation of
energy, i.e., “waste to energy.” This energy can be used for heating and electricity
generation purposes. The third benefit of this technique is that it leads to detoxification, i.e., killing of microbes and other pathogenic organisms within the waste. In
modern incinerators, waste is burned at high temperatures under controlled conditions. This combustion of waste leads to the generation of gases like CO 2 , SO 2 , NO X ,
and HCl and some toxic gases like dioxins and furans that are hazardous at very low
concentrations. The process of incineration also produces a particular matter (fly ash,
soot, and dust), incinerator residue (bottom ash), process water, and some heavy
metals (Pichtel 2005). The modern incinerators are equipped with extensive emission control devices like fabric baghouse filters, acid gas scrubbers, and electrostatic
precipitators to remove the fly ash and gaseous by-products. The ash is ultimately
disposed into the landfill site, and if it is found to contain toxic metals, it should be
treated as hazardous waste. The most critical factors that determine the combustion
effectiveness in incineration are (1) the temperature in the combustion chamber,
(2) the time duration for the combustion, (3) the rate of mixing or turbulence, and
(4) the quantity of oxygen present for combustion process (Narayana 2009).
6.3.1.2 Pyrolysis
It is a thermal process, in which biomass is heated at a temperature ranging from
300 to 1000
C in the absence of oxygen and air. It is used to treat the waste to obtain
a solid residue, liquid oil, and gases. During this process, the biomass breaks into
different phase state products, coexisting solids, liquids, and gases at the end of the
process. The ratio is heavily dependent on the velocity of the process (Dhyani and
Bhaskar 2019). It is also called as destrictive distillation as it is endothermic process.
6.3.1.3 Landfills
Landfills are the sites where waste is deposited onto or into the land that results in
leachate leakage and release of landfill gas. Leachate leakage is dependent upon the
relative permeability of the landfill liner. Landfill leachate is responsible for polluting groundwater supplies. As waste decomposes, a combination of chemical, thermal, and microbial reaction releases gases (US Environmental Protection Agency
1999). Landfill gas is a combination of methane and carbon dioxide in almost equal
parts. The remaining 0.01–0.6% is composed of carcinogenic volatile organic
compounds, such as benzene, toluene, xylenes, etc. A landfill site is an area of
land where waste is deposited. It is intended to prevent or minimize the interaction of
waste and its surroundings, especially the groundwater. It is the most common
practice in India to tackle waste.
Landfills are generally classified into three categories as follows.
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S. I. Singh et al.
incineration is the reduction in the volume of waste (>90%) that ultimately extends
the lifetime of the land disposal facility. The second purpose is the generation of
energy, i.e., “waste to energy.” This energy can be used for heating and electricity
generation purposes. The third benefit of this technique is that it leads to detoxification, i.e., killing of microbes and other pathogenic organisms within the waste. In
modern incinerators, waste is burned at high temperatures under controlled conditions. This combustion of waste leads to the generation of gases like CO 2 , SO 2 , NO X ,
and HCl and some toxic gases like dioxins and furans that are hazardous at very low
concentrations. The process of incineration also produces a particular matter (fly ash,
soot, and dust), incinerator residue (bottom ash), process water, and some heavy
metals (Pichtel 2005). The modern incinerators are equipped with extensive emission control devices like fabric baghouse filters, acid gas scrubbers, and electrostatic
precipitators to remove the fly ash and gaseous by-products. The ash is ultimately
disposed into the landfill site, and if it is found to contain toxic metals, it should be
treated as hazardous waste. The most critical factors that determine the combustion
effectiveness in incineration are (1) the temperature in the combustion chamber,
(2) the time duration for the combustion, (3) the rate of mixing or turbulence, and
(4) the quantity of oxygen present for combustion process (Narayana 2009).
6.3.1.2 Pyrolysis
It is a thermal process, in which biomass is heated at a temperature ranging from
300 to 1000
C in the absence of oxygen and air. It is used to treat the waste to obtain
a solid residue, liquid oil, and gases. During this process, the biomass breaks into
different phase state products, coexisting solids, liquids, and gases at the end of the
process. The ratio is heavily dependent on the velocity of the process (Dhyani and
Bhaskar 2019). It is also called as destrictive distillation as it is endothermic process.
6.3.1.3 Landfills
Landfills are the sites where waste is deposited onto or into the land that results in
leachate leakage and release of landfill gas. Leachate leakage is dependent upon the
relative permeability of the landfill liner. Landfill leachate is responsible for polluting groundwater supplies. As waste decomposes, a combination of chemical, thermal, and microbial reaction releases gases (US Environmental Protection Agency
1999). Landfill gas is a combination of methane and carbon dioxide in almost equal
parts. The remaining 0.01–0.6% is composed of carcinogenic volatile organic
compounds, such as benzene, toluene, xylenes, etc. A landfill site is an area of
land where waste is deposited. It is intended to prevent or minimize the interaction of
waste and its surroundings, especially the groundwater. It is the most common
practice in India to tackle waste.
Landfills are generally classified into three categories as follows.
92
S. I. Singh et al.