Solid wastes, Incineration

Hearth incinerators. This type of incinerator is designed primarily to incinerate solid waste. Solids are moved through the combustion chamber mechanically using a rake. 

To deal with the hazardous status of ashes from CCA-treated wood, the arsenic must either be extracted or the ashes would need to be encapsulated through solidification/stabilization. Hypothetically, the recovery and reuse of arsenic from the incineration of CCA-treated wood could reduce arsenic mining and imports. However, arsenic use has declined in recent years (Chapter 5) and there is little economic incentive to incinerate solid wastes and recover any volatile arsenic (Leist, Casey and Caridi, 2000, 126, 127). 

Dioxins are some of the most toxic chemicals known to science. Dioxins are unwanted by products of a wide range of manufacturing processes including smelting, chlorine bleaching of paper pulp, and the manufacturing of some herbicides and pesticides. In terms of dioxin release into the environment, waste incinerators (solid waste and hospital waste) are often the worst culprits, due to incomplete burning [115]. One of the most toxic chemical in the class is 2,3,7,8-tetrachlorodibenzo-/ /Y/-dioxin (TCDD) and probably the most toxic compound ever synthesized by man. 

Of the 200 million tons of municipal solid waste collected in the United States in 1993 (1), 22% was recycled while 62% was placed in landfills and 16% incinerated (2). Plastics comprised 9.3% of these materials. The number of U.S. residential collection programs increased from 1,000 in 1988 to more than 7,000 involving more than 100 million people in 1993 (2). Approximate 1994 U.S. recycling rates are given in Table 1. 

D. Tillman, A. Rossi, and K. Vick, Incineration of Municipal and Iia rdous Solid Wastes, Academic Press, Inc., San Diego, Calif., 1989. 

Pollutant Emissions from Solid Waste Incinerators. 

R. S. Magee, Plastics in Municipal Solid Waste Incineration A Eiterature Study, Hazardous Substance Management Research Center, New Jersey Institute of Technology, Mar. 1989. 

Disposal The final func tional element in the sohd-waste-management system is disposal. Disposal is the ultimate fate of all solid wastes, whether they are wastes collected and transported direc tly to a landfQl site, semisolid wastes (sludge) from industrial treatment plants and air-pollution-control devices, incinerator residue, compost, or other substances from various solid-waste processing plants that are of no further use. 

Reduction of volume of solid wastes through burning (incineration)... 

Incineration with Heat Recovery Heat contained in the gases produced from the incineration of solid wastes can be recovered as steam. The low-level heat remaining in the gases after heat recoveiy can also be used to preheat the combustion air, boiler makeup water, or solid-waste fuel. 

Concentration of WTE Incinerators The total number of municipal waste incinerator facihties as hsted in the Solid Waste Digest, vol. 4, no. 9 September 1994 (a publication of Chartwell Information Publishers of Alexandria, VA) is 62. See Table 25-69, which covers over 200 existing units. The wastes burned in these facilities totals 8.44 percent of total municipal wastes managed in landfills, incinerators, and transfer stations. This amounts to 88,470 tons per day combusted municipal waste. 

TABLE 25-69 Solid Waste Price Index, WTE Incinerator Intake TPD-Tip Fee, September 1994... 

Section 129 of the CAAA of 1990 applies to a range of solid waste incinerators including MWCs, medical waste incinerators (MWls)... 

EPA must issue New Source Performance Standards (NSPS) for any solid waste incineration unit not covered by another deadline lor issuance of such standards. 

EPA must issue NSPS for solid waste incineration units combusting industrial or commercial waste. (See May 15, 1992 action.)... 

Wastes Anaerobic breakdown Admixture of effluents Open handling of effluents or wastes Atmospheric venting Solid wastes Uncontrolled incineration... 

Contaminated solid wastes are generally incinerated, and the flue gases are scrubbed. The emissions levels cited in Table 4 are those recommended by the World Bank Organization that should be achieved. 

The specific molecular mechanisms by which PCDDs and PCDFs are initially formed and become part of the PIC remain largely unknown and are theoretical. The theoretical basis for conjecture is derived primarily from direct observations in municipal solid waste incinerators. The emissions of... 

Venmri scrubbers have been applied to control PM emissions from utility, industrial, commercial, and institutional boilers fired with coal, oil, wood, and liquid waste. They have also been applied to control emission sources in the chemical, mineral products, wood, pulp and paper, rock products, and asphalt manufacrnring industries lead, aluminum, iron and steel, and gray iron production industries and to municipal solid waste incinerators. Typically, venturi scrubbers are applied where it is necessary to obtain high collection efficiencies for fine PM. Thus, they are applicable to controlling emission sources with high concentrations of submicron PM. 

USATHAMA) completed a trial burn of explosive, contaminated soil in a rotary kiln (Noland, 1984). Soil contaminated from red and pink water lagoons was successfully burned. A transportable rotary kiln yrstem was set up. The technology by Therm-All, Inc., had been used in industry for destruction of solid wastes. The normal screw feed system was not used, due to fear of a soil explosion during the extruded plug feed process. Therefore, the soil was placed in combustible buckets and individually fed by a ram into the incinerator. The feed rate was 300 to 400 Ib/hr and the operational temperature was 1200° to 1600°F in the kiln and 1600° to 2000°F in the secondary chamber. 

Permitting of enviromnentally sound solid waste management facilities, including landfills and incinerators... 

Solid wastes arc disposed of by two basic methods. The first is by some type of dumping or landfill procedure the second is by incinerating (burning) the waste. This section focuses on incinerators, namely the rotary kiln, liquid injection, fuidized-bed, and multiple-hearth dc ices, which are the four types... 

Fluidized-bed process incinerators have been used mostly in the petroleum and paper industries, and for processing nuclear wastes, spent cook liquor, wood chips, and sewage sludge disposal. Wastes in any physical state can be applied to a fluidized-bed process incinerator. Au.xiliary equipment includes a fuel burner system, an air supply system, and feed systems for liquid and solid wastes. The two basic bed design modes, bubbling bed and circulating bed, are distinguished by the e.xtent to which solids are entrained from the bed into the gas stream. 

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