TREATMENT OF BIO-HAZARDOUS WASTEWATER BY FENTON OXIDATION COMBINED WITH COAGULATION/ FLOCCULATION PRETREATMENT: A CASE STUDY

摘要

A vehicle mounted full-scale facility with a sequential combination of coagulation/flocculation (CF) and Fenton oxidation (FO) processes was used to treat BHW from thirteen biotechnology enterprises. The facility with a capacity of 6 tonnes/day consisted of three stages: pH adjustment, CF pretreatment and FO. The appropriate conditions with a view to practical application were as follows: 70 mg/1 of polymeric aluminum ferric chloride sulfate (PAFCS) for CF; 1.5 g/1 of H_2O_2 at initial pH 3.5 and 12 ℃ for FO. The [H_2O_2]/[Fe~(2+)] molar ratio was controlled at 20 throughout all FO experiments. After continuous operation for 30 days at 6.3±5.1℃, the average total plate count (TPC), adeno-sine triphosphate (ATP) and inhibition ratio of luminescence (IR) were reduced from 3.1xl05 to 4 cfu/ml, 25265 to zero RLU/ml and 55 to -0.9%, respectively, which indicate that the treatment was very effective. The average removals of chemical oxygen demand (COD), soluble COD (SCOD), linear alkylbenzene sulfonates (LAS), suspended solids (SS), ammonia nitrogen (NH3-N), total nitrogen (TN) and total phosphorus (TP) were 92, 89, 96, 74, 67, 49 and 98%, respectively. The cost of all chemicals to treat a tonne of BHW was about 1.338 US$, with H_2O_2 accounting for 74.7% of the total cost. The CF-FO combined process offers a safe, effective and feasible treatment for BHW, even if applied at low temperatures.