Pilot study on the treatment of coking wastewater with a three-stage upflow hydrolytic acidification sludge bioreactor

This study employed three-stage upflow hydrolytic acidification sludge bioreactor+A2O activated sludge process to treat coking wastewater, focusing on the reactor’s impact on the efficiency of organic matter removal and the mitigation of influent water fluctuations. The effects of the pilot biochemical system on the treatment of coking wastewater and the distribution of microorganisms in the reactors were compared with the existing system. The pilot results revealed that an average COD removal rate of 57.72% for the three-stage upflow reactor, with a maximum removal rate of 66.67% and fluctuation level at 29.85% of influent fluctuations were achieved. After reaching design-loading, the entire pilot system exhibited an average COD removal rate of 91.38%, with peak of 95.73%, and an ammonia removal rate of 97.20%. Characteristic pollutant analysis indicated that removal rates for cyanides and sulfides were 81.53% and 92.07%, respectively. High-throughput sequencing of microorganisms showed a more diverse microbial population in the pilot reactor, particularly in the enrichment of microorganisms for specific pollutant removal. The pilot process of three-stage upflow hydrolytic acidification sludge bioreator+A2O activated sludge treatment resulted in a shorter retention time, which provided a new process direction for coking wastewater.