Research Of O-M Biological Treatment Of Coke Plant Wastewater By A～2-O-M

Coke plant wastewater is difficult to treat, because of it containing high concentration of toxic and refractory organics. Many coke plants have employed the conventional biological process to treat it, which usually was not able to meet the discharge standards. With physical or chemical process, which could meet the demand of drainage by environmental protection, but the cost was very expensive. It is imperative to develop a kind of coke plant wastewater treatment, which should be economic and technique feasible.The anaerobic-anoxic-aerobic-hybrid biological reactor(A2-O-M) was used for coke plant wastewater treatment in this study.The experimental results showed that this system was efficient and stable in COD and NH3-N reductions. The effluent COD and NH3-N removal rate concentration 370.6 — 2336.8mg/L and 146.24—202.45mg/L can achieve 75.54 and 99.26% respectively, when the total HRT of the whole system was 50 hours.The experimental results showed that the aerobic effluent COD, NH3-N and BOD5 when inflow concentration were 184.4— 2980.2mg/L, 4.81 — 155.32 mg/L, 21.6— 311.04 mg/L could achieve 208.27mg/L, 0.80mg/L and 13.71mg/L respectively in 20 hours, under the conditions of pH=6.73—8.60, temperature=30.9— 32.2℃ and DO=1.52—3.92mg/L. The hybrid biological reactor effluent COD, NH3-N and BOD5 can achieve 167.27mg/L, 0.63mg/L and 12.46mg/L respectively in 8 hours, under the conditions of pH=6.84—9.02, temperature=32.1—34.TC and DO =2.58—4. 10mg/L.Employing Matlab, a mathematical operation tool, inspected the experimental results and calculated the long-term effluent water quality. Without variation of system condition, the point estimation of effluent COD could achieve 167.27mg/L, the probability was0.99839 and the confidence interval was 139.39~195.16mg/L. The probability of which is smaller than 150mg/L was 0.8974. The point estimation of effluent NH3-N could achieve 0.63mg/L, the probability was 1 and the confidence interval was 0.0471 ~ 1.2129mg/L.Not have to feeding carbon and alkali, the water quality of effluent from system of A2-O-M could meet the secondary national standard about wastewater discharge(GB8978-1996). The concentration of COD and ammonia nitrogen was less than 150mg/L and 25mg/L each. This technology is economic and technique feasible.