BIOLOGICAL TREATMENT OF WASTE-WATER FROM NITROSOPHENOL PRODUCTION

Nitrosophenol is an intermediate organic chemical used in dye synthesi s. Wastewater from nitrosophenol production is high-strength in terms of chemical oxygen demand (COD), phenol, and total dissolved solids co ncentrations. Previous reports on treatment of wastewaters containing nitrosophenol addressed chemical oxidation methods. Biological treatme nt of nitrosophenol wastewater was evaluated in this study using a ben ch-scale sequencing batch reactor. Substrate inhibition by phenol was observed, but methods to overcome inhibitory effects were developed. B iodegradation of nitrosophenol was concluded to occur by co-metabolism in the presence of phenol, based primarily on COD balances and by rul ing out abiotic mechanisms of nitrosophenol removal. The biomass devel oped in the reactor was unable to grow on nitrosophenol as a sole carb on source, and consisted predominantly of two eukaryotic morphotypes a nd a dispersed bacterial population. Based on results from the study, nitrosophenol wastewater is amenable to biological treatment but the e ffluent may require further treatment before discharge.