Immobilization of Dominant Bacteria by Polyvinyl Alcohol and Its Effect on COD Removal from Coking Wastewater

Abstract

Coking wastewater is one of the most difficult wastewater to treat in industry, especially in COD removal. In this study, polyvinyl alcohol was used as carrier to immobilize the dominant bacteria which could efficiently remove COD from coking wastewater. Through single factor experiments and microscopic observation, the optimum immobilization conditions were determined to be 10% PVA concentration and 1% bacterial sludge concentration. Compared sludge containing dominant bacteria with polyvinyl alcohol carrier under optimal conditions, the results showed that polyvinyl alcohol carrier had better COD removal effect than sludge containing dominant bacteria. When the initial COD concentration was 1050 mg/L, the removal rate of COD by carrier arrived 84.23%, while that of sludge arrived 77.46%. In addition, the carrier exhibits better tolerance in treating coking wastewater with high concentration of COD than sludge, and its degradation capacity can continuously maintain more than 70% for a long time.