Dioxin abatement strategies and mass balance at a municipal waste management plant.
Since the thermal management of municipal solid waste (MSW) is considered to be one of the major sources of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), the purpose of this study was to show the results of a dioxin abatement program performed in the municipal waste incineration (MWI) plant of Tarragona (NE Spain). Previously, stack gas emission levels of PCDDs/PCDFs around 3.26 ng I-TEQ/Nm3 were determined when the gas-cleaning system consisted only of an electrostatic precipitator (ESP). Decreased levels, below 0.1 ng I-TEQ/ Nm3, were observed when a new air pollution control system was installed. This new system was improved by the injection of activated carbon, which helped to lower the levels of PCDDs/PCDFs to around 0.01 ng I-TEQ/Nm3. Considering the absence of a particular impact on herbages, soils, and ambient air around the plant, as reported in previous works, and the hypothesis that a modern installation could become a sink for dioxins instead of a source, a dioxin mass balance was evaluated. The study compared in a large-scale MWI plant the levels of PCDDs/PCDFs of all input and output contributors (MSW, ambient air, stack gas emission, fly ash, and slag) forming part of the inventory collected in various monitoring campaigns. The findings revealed a remarkable homogeneity in output values (between 1.19 and 2.62 ng I-TEQ/yr) in contrast to the large variability observed in input values. In the first sampling campaign, the dioxin content in MSW was around 64.15 ng I-TEQ/kg, and a negative balance of 7.68 g I-TEQ/yr was calculated. However, in the latest campaign, levels were about 2.36 ng I-TEQ/kg MSW, resulting in a positive balance of 2.28 g I-TEQ/yr.
Abad
E
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Mass Spectrometry Laboratory, Department of Ecotechnologies, IIQAB-CSIC, Barcelona, Spain.
Adrados
M A
MA
Caixach
J
J
Rivera
Josep
J
D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control*; D001572:Benzofurans / Q000032:analysis*; D004147:Dioxins / Q000032:analysis*; D004784:Environmental Monitoring; D017745:Incineration; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis*; D012037:Refuse Disposal / Q000379:methods*; D012989:Soil Pollutants / Q000032:analysis*
D000393:Air Pollutants; D001572:Benzofurans; D004147:Dioxins; D000072317:Polychlorinated Dibenzodioxins; D012989:Soil Pollutants; C023614:dibenzofuran