Application effect of improved AAO process in coal mine domestic sewage treatment

LI Xuanlong; LIU Gangchao; CHENG Jining

doi:10.11799/ce202508006

Abstract：Coal mine domestic sewage has the characteristics of large fluctuation of water quality,low concentration of organic matter,high concentration of suspended solids,and high cost of sludge disposal far away from the city.It is limited by environmental protection policies and needs to be fully reused.And it is difficult to meet the demand using the traditional treatment process.In this paper,the improved AAO process(AAO+suspended filler process)is taken as the research object,and its application effect and optimization direction in coal mine domestic sewage treatment are discussed.Through the actual case of a coal mine in Yan'an City,the analysis shows that the process can still operate stably under low carbon-nitrogen ratio(BOD5/N=5.5)and low temperature(-21℃)conditions,and the effluent quality is better than the design standard.The removal rates of COD,BOD5,SS,NH3-N and TP are 97.8%,99.7%,99.7%,93.5%and 87.1%,respectively,which meet the requirements of green plot sprinkling and coal washing water.The improved AAO process has high biological stability,good and stable effluent quality,less sludge production and good sedimentation performance.In addition,the improved AAO process has the flexibility of operation and design,which is suitable for the upgrading and expansion of existing treatment stations.Optimization studies have shown that adjusting the reflux method and introducing sludge in-situ reduction technology can further improve phosphorus removal.Therefore,improved AAO processes(AAO+suspended packing media process)have become the main process for coal mine domestic sewage treatment.