Bioaugmentation as a tool to enhance the removal of refractory compound in coke plant wastewater

Abstract

Pollution caused by coal conversion wastewater has been a severe problem for decades in China due to the use of coal as the main energy source. An aerobic–anoxic–oxic (A1–A2–O) system was developed for treating coke plant wastewater and good results were obtained. GC/MS analysis indicated that the main ingredients of the effluent were aromatic and heterocyclic compounds, alkanes and phthalic acid esters etc. Bioaugmentation with specialized microorganism could be a powerful tool to improve the wastewater treatment processes. In this study, quinoline, which was poorly removed by the A1–A2–O system, was chosen as a target pollutant, and a quinoline-degrading bacterium, identified as Burkholderia pickettii was used as bioaugmentation microorganism. The feasibility of bioaugmentation in combination with A1–A2–O system was investigated. The performance of the A1–A2–O system and the contribution of each stage to COD removal were investigated. The contribution of anaerobic, anoxic and oxic reactors to COD removal was 25, 16 and 59%, respectively. The results of bioaugmentation experiments showed that the oxic reactor, to which the aerobic microorganism was added, was the best location of bioaugmentation in the A1–A2–O system. Bioaugmentation could be used as an efficient and effective method of improving the removal efficiency of recalcitrant organic compounds from industrial wastewater.