Stack emissions, municipal solid waste

Pitea D, Lasagni M, Bonati L, et al. 1989c. The combustion of municipal solid wastes and PCDD and PCDF emissions Part 2. PCDD and PCDF in stack gases. Chemosphere 18 1465-1474. 

Theoretical studies into the mechanisms of formation of PCDD/Fs in combustion systems, with the specific aim of elucidating emission control strategies, commenced in the early 1980s. Seminal contributions7-9 examined free radical, homogeneous gas-phase reactions in the hot, combustion zone of municipal solid waste (MSW) incinerators, and concluded that this formation mechanism could not account for measured concentrations of PCDD/Fs in incinerator stack emissions. Measurements taken at various stages of the combustion and gas cleaning train of a MSW incinerator at Tsushima, Japan,... 

Incineration of rubber tires, paper, and municipal waste is an additional source of atmospheric selenium. Hashimoto et al. (1970) reported selenium concentrations in rubber tires to be 1.3 mg/kg. Seventy different kinds of paper have been found to contain selenium (West 1967). Combustion of municipal solid waste results in stack emissions ranging from 0.00098 to 0.00216 pounds (0.44-0.98 g) of selenium per ton of refuse (Johnson 1970). 

TCDD was detected in stack emissions, slag, or wash water, while some PCDDs were detected only in ppt amounts in stack emission (Brenner etal. 1986). The levels of PCDDs and PCDFs in the incinerator flue gases were found to be slightly high when the amount of wet leaves in the municipal solid waste was higher (Marklund et al. 1986). The increase in polyvinyl chloride (PVC) content in the waste feed did not produce emissions with detectable concentrations of dioxins and dibenzofurans (Carrol 1988 Giugliano et al. 

Consumer batteries are generally smaller and are discarded with other products in the municipal solid waste. When the waste reaches a landfill, water is leached and then nickel, cadmium, and mercury are extracted from the used and broken batteries. High concentrations of the metals are sorted out from the landfill base. When the waste reaches the incinerators, the batteries contribute high levels of metal fumes to the stack emissions and ash, which escalates the cost of environmental control. Battery producers claim that used batteries accounted for close to 1.5 million metric tons of municipal from solid waste. However, this quantity is less than 1% of the total municipal solid waste generated. This solid waste contains about 67% of the lead, 90% of the mercury, and more than 50 percent of the cadmium. In countries where county and municipal regulators mandate the removal of Pb-acid batteries from the municipal solid-waste incinerators and landfills, they require safe disposal of used batteries with appropriate certification. 

Prom an engineering viewpoint, the most direct way to estimate pollution emissions from an industrial plant is by mass balance. The concept is mass in = mass out —that is, everything the purchasing department buys and is delivered to the plant must somehow leave the plant, whether within the manufactured product as solid waste to a landfill as air emissions either through a stack or vent or as liquid waste either to an on-site treatment plant or to the sewer and the municipal wastewater treatment plant. 

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