Performance of Baffled Biological Aerated Filter/Stabilization Pond for Domestic Sewage Treatment in Small Towns

Based on case study of WWTP in a small town in Three Gorges Reservoir Region,the design characteristics and performance of the combined process of baffled biological aerated filter(BBAF) and stabilization pond were introduced.When the influent flow rate is 800 m3/d,and the influent COD,NH+4-N,TN and TP are 14 to 315 mg/L,1.00 to 41.72 mg/L,4.90 to 50.16 mg/L and 0.30 to 3.79 mg/L respectively,the effluent can meet the first level B criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB 18918–2002).The combined process has good adaptability to low influent concentration and large fluctuation in influent quality.Changes of season and temperature have no obvious effect on the removal of COD and TP,while the removal rates of NH+4-N and TN are decreased obviously in winter.Stabilization pond can further purify the effluent of the BBAF,playing a good guarantee role.