摘要
Coking wastewater poses a higher challenge to traditional biological treatment processes due to its strong biological toxicity, high corrosiveness, and high COD/TN ratio. The exploration of new biological processes is of great significance to the feasibility of meeting special water quality standards and the economy of the process. Based on these considerations, this study constructed a new type of Aerobic-Hydrolysis-Aerobic (OHO)-Membrane Bioreactor (MBR) combined process for coking wastewater treatment. The actual coking wastewater was used to carry out an on-site small test study and investigate the treatment effect of typical pollutants in the coking wastewater. Combining the measurement results of process operating parameters and water quality indicators, the conversion characteristics of typical pollutants in the OHO-MBR process were analyzed. Under stable operation conditions, the actual operation results of coking wastewater treated by OHO-MBR process showed that, under the conditions of HRT = 56 h and the average influent COD, TN, NH+4-N and SCN?-N of 3 063, 146, 27.3 and 85.1 mg·L?1, respectively, the average removal rates of COD, TN, NH+4-N and SCN?-N achieved by the combined process were 85.9%, 65.4%, 95.1% and 98.6% even at low ambient temperatures(10~20 ℃), respectively. After 3 months running of the process with the membrane flux of 20 L·(m2·h)?1 for the membrane module, the transmembrane pressure maintained below 10 kPa, which showed the preliminary feasibility of the combined process to treat actual coking wastewater. The potential direction of the process to further improve the effect of pollutant treatment was clarified. The existence of the membrane module in the O2 reactor of OHO could remove the suspended solids and colloidal components in the coking wastewater, effectively intercepted and enriched the special functional microorganisms that were not easy to proliferate in the conventional process. The loading rate and shock resistance capability increased for the process without the need for large-scale transformation of infrastructure facilities, and it can be used as an improvement technology option for the existing process to improve the quality of the effluent.
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