Atmospheric Release of Organic Chlorinated Compounds from the Activated-Sludge Wastewater Treatment Process.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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The objective of this study was to investigate some of the potentially controlling factors influencing the atmospheric release of volatile organic compounds from the activated-sludge sewage treatment process. The study consisted of field studies at an activated-sludge treatment plant and laboratory studies with a bench-scale aeration vessel. The field studies were designed to evaluate the wastewater and airborne concentrations of three chlorinated compounds hexachloro-bicycloheptadiene Hex-BCH, heptachlorobicycloheptene Hex-VCL and chlordene at various locations of the plant. the laboratory aeration unit was used to investigate the influence of aeration rate, suspended solids concentration, and detergent level on the rate of stripping of Hex-BCH and chloroform from a simulated wastewater solution. The field study revealed that the highest wastewater concentrations of the test compounds Hex-BCH, Hex-VCL and chlordene were found in the sludge of the aeration basins, which suggest significant adsorption of the test compounds to the solids. Comparison of the airborne concentrations of the different aeration basin types at the plant contact, stabilization and digestion, suggested higher release from the contact and stabilization basins than the digestion basins. The higher air flow through the contact and stabilization basins is considered to be the primary factor partially responsible for this. In addition, the digestion and stabilization basins have much higher suspended solids levels than the contact basins, which may suppress the aerial stripping.
- Water Pollution and Control