Treatment of coke oven wastewater in an anaerobic–anoxic–aerobic moving bed bioreactor system

Abstract

AbstractIn this work, sequential moving bed bioreactor (MBBR) system with mixed heterogeneous biomass was selected for the treatment of coke oven wastewater (CW). The reactors were arranged in anaerobic (R1)–anoxic (R2)–aerobic (R3) sequence. CW was collected from an industrial site which contains phenol, ammonia, sulfate, iron, oil, and grease. Few heavy metals (cadmium, lead, and cobalt) were also detected in CW at low concentrations. Raw CW was pretreated by primary settling process to remove high solid concentrations. Thereafter, CW was spiked with synthetic pollutants to make the picture of model industrial wastewater. Phenol (1,350 mg/L), ammonia-N (500 mg/L), thiocyanate (800 mg/L), pyridine (50 mg/L), m-, o-, and p-cresols (50 mg/L each) were added as synthetic pollutants in CW. The system was operated at 6 d hydraulic retention time. R1 showed only less phenol (2–5%) and chemical oxygen demand (COD) (~2%) removal. However, R2 and R3 removed significant amount of thiocyanate (>85%), cresols (~88%)...