Abstract:station of Zhengtong Coal Mine and meet the improved wastewater discharge standard, a process of "synchronous biological oxidation tank (SBOT) + micro flocculation filtration" was adopted to upgradethe original system. The SBOT process has the advantages of large biomass and high treatment capacity,and can simultaneously remove COD and ammonia nitrogen. The operation results show that the averageconcentrations of COD, TN, ammonia nitrogen, TP and SS in the effluent of the upgraded system are12.3, 7.5, 1.1, 0.29 and 6.2 mg/L. The effluent quality stably meets the requirements of integratedwastewater discharge standard of Yellow river basin in Shaanxi Province (DB 61/224—2018), as wellas the requirements of greening irrigation, road flushing, water supply of coal preparation plants andvehicle flushing. Close-