NITRIFICATION INHIBITION AT LOW TEMPERATURE BY THE AZO DYE ACID BLACK 1

摘要

A municipal wastewater treatment plant (WWTP) receiving industrial dyeing dischargecontaining acid black 1 (AB1) failed to meet discharge limits, especially during the winter.Dyeing discharge was mixed with domestic sewage in volumetric ratios reflecting the rangereceived by the WWTP and fed to sequencing batch reactors at 22℃ and 7℃. Analysis of thevarious nitrogen species revealed complete nitrification failure at 7℃ with more rapidnitrification failure as the dye concentration increased; slight nitrification inhibition occurred at22℃. Dye-bearing wastewater also reduced COD removal at 7oC and 22℃ and increasedeffluent TSS at 7℃. Activated sludge quality at 7℃ deteriorated, as indicated by excessivefoaming and the presence of filamentous bacteria and by decreased endogenous and exogenousoxygen uptake. Decreasing AB1 loading led to partial nitrification recovery. Eliminating thedye-bearing discharge to the full-scale WWTP resulted in improved performance bringing theWWTP into compliance with discharge limits.