Anaerobic Treatment of a Simulated High-Strength Industrial Wastewater Containing Chlorophenols

An anaerobic fluidized-bed granular activated carbon (GAC) reactor employing carbon replacement was evaluated for the treatment of a simulated high-strength industrial wastewater containing inhibitory concentrations of chlorophenols. The reactor was fed 2 000 to 5 900 mg/L acetic acid; 1 000 to 3 000 mg/L phenol; 1 200 mg/L ortho-chlorophenol (2-CP); 600 mg/L 2,4-dichlorophenol (2,4-DCP); and 150 mg/L 2,4,6-trichlorophenol (2,4,6-TCP). The effects of varying the carbon replacement rate, the bulk operating pH, and the organic loading on reactor performance were investigated. The system was highly effective for treating the wastewater and an overall chemical oxygen demand (COD) removal greater than 98% was achieved. Carbon replacement resulting in a GAC solids mean retention time (SMRT) of 100 days was necessary to control the buildup of an inhibitory degradation byproduct, para-chlorophenol (4-CP).