Study Of Field Experiment On Small Town Sewage With Denitrifying Phosphate Accumulating Bacteria

The biological denitrifying phosphorus removing simultaneously has being a difficult problem in the wastewater treatment domain. At the base of laboratory experiment, this paper developed a new denitrification and phosphorus removal process aiming at treating small town sewage and carried out the field experiment.The new designed treating process — TSS-SBR(Two-Sludge Switching -SBR) is composed of a main reactor and two smaller sludge hoppers. The hoppers contains different actived sludges, witch works by switching between the main reactor and the hopper. Denitrifying phosphate accumulating bacteria (DPB) play the mostly role of denitrification and phosphorus removal, at the same time the poly-phosphate accumulating organisms(PAOs) are also used in order to avoid the disadvantage of denitrifying phosphorus.We applied this wastewater treating process in treating septic tank wastewater and hotel wastewater, results showing that: when the COD, NH₄⁺, TP of influent are 200-500 mg/L, 20-60 mg/L, 2-9 mg/L and the temperature of the wastewater is higher 18℃, effluent are less than 50 mg/L, 1 mg/L, 0.5 mg/L respectively, and TN of effluent is less than 15 mg/L. The quality of the effluent water can meet the first grade of Discharge standard of pollutants for municipal wastewater treatment plant (GB18918-2002). The effects of temperature and DO, the change of MLSS and ORP had also been discussed. By compareing with other wastewater processes, it is proved that this new TSS-SBR process could reduce aeration, project investment, output of sludge and running expenses.However, this new TSS-SBR process need higher automatization and its scale could not oversize. This paper will be the reference and application for treating the small town sewage in the future.