Phenolic compound removal in coal-gas wastewater by O₃-IBAC

Acclimated bacteria with high ability of phenolic compound biodegradation were immobilized on granular activated carbon to form Immobilization Bacteria Activated Carbon (IBAC). Ozone and IBAC combined process was applied to treat coal-gas wastewater containing phenolic compounds. Optimum ozone dosage and contact time were determined to be 18 mg/L and 20 min. Although pre-oxidation contributed little to the removal of total organic carbon (TOC), it changed the characteristics and structure of organic substance in the wastewater. By using of ozone-IBAC treatment, when influent contained 500 mg/L COD and 95 mg/L phenol, the removal rates of COD and phenol are higher than 80% and 92%. After 6 months of operation, acclimated bacteria abundance maintained above 6.1 × 10³ cfu/(g carbon) and kept in dominant status. Moreover, bacteria distribute evenly on the activated carbon. The long-term steady viability and high biodegradation efficiency of acclimated bacteria are discussed according to the ecological principle.