Biological Treatment of Wastewater from Nitrosophenol Production

Abstract

Nitrosophenol is an intermediate organic chemical used in dye synthesis. Wastewater from nitrosophenol production is high‐strength in terms of chemical oxygen demand (COD), phenol, and total dissolved solids concentrations. Previous reports on treatment of wastewaters containing nitrosophenol addressed chemical oxidation methods. Biological treatment of nitrosophenol wastewater was evaluated in this study using a bench‐scale sequencing batch reactor. Substrate inhibition by phenol was observed, but methods to overcome inhibitory effects were developed. Biodegradation of nitrosophenol was concluded to occur by cometabolism in the presence of phenol, based primarily on COD balances and by ruling out abiotic mechanisms of nitrosophenol removal. The biomass developed in the reactor was unable to grow on nitrosophenol as a sole carbon source, and consisted predominantly of two eukaryotic morphotypes and a dispersed bacterial population. Based on results from the study, nitrosophenol wastewater is amenable to biological treatment but the effluent may require further treatment before discharge.