Identification of - unsaturated aldehydes as sources of toxicity to activated sludge biomass in polyester manufacturing wastewater

摘要

Wastewater generated in industrial production processes are often contaminated by hazardousnchemicals. Characterization by means of toxicity-directed analysis is useful for identifying whichnfractions of a waste stream possess the most toxicity. We applied this approach to evaluate toxicncomponents of a polyester manufacturing wastewater. Using the reduction in oxygen uptake ratenof activated sludge as an indicator of toxicity, it was determined that increasing the pH fromn3 to 11 followed by air stripping significantly reduced the toxicity of the wastewater. Comparativenheadspace GC/MS analysis of wastewater at different pHs selected a group of Volatile OrganicnCompounds (VOCs) associated with the observed effect of air stripping at pH 11. Ten of thesencompounds were identified as a,b unsaturated aldehydes (acrolein (2-propenal) congeners);nthese compounds are known to be toxic as well as mutagenic. Confirmation that thesencompounds were a cause of toxicity was achieved by demonstrating that removal of thesencompounds by air stripping significantly reduced the wastewater mutagenic potency in anSalmonella mutagenicity assay. Formation of these volatile compounds by base catalyzed aldolncondensation at pH 11 may account for the effectiveness of air stripping in reducing toxicity.nTo date there is no record in the literature about the toxicity and presence of acrolein congenersnin polyester manufacturing wastewater.