A Review of Hybrid Process to Treat Coal Gasification Wastewater
Due to the presence of complicated and considerable amounts of toxic compounds such as phenolic compounds, thiocyanate and ammonium, coal gasification wastewater (CGW) would cause a serious environmental problem. Conventional treatment of CGW includes a series of biological treatment (mostly anoxic-aerobic process and activated sludge process) after a physico-chemical pretreatment to reduce the concentrations of phenols and ammonium. Although quite effective, these processes are still not enough to meet the strict requirements of the National Discharge Standard of China. To find more efficient way to treat CGW, a serious of hybrid processes were reviewed in this study. Through this review we found that A2O combined with MBR (anaerobic-anoxic-aerobic membrane reactor) can effectively remove COD, total organic carbon, NH4+ -N, total phenols and total nitrogen (TN).