摘要
Abstract
Anoxic-oxic(AO)is widely used as a classical nitrogen removal process in small and medium-sized wastewater treatment plants(WWTPs).With the continuous improvement of wastewater discharge requirements,it is of great significance to upgrade the existing WWTP.In this case,the designed treatment water of the WWTP is 500 m3/d.Due to the increased requirements for TN and CODCr discharge,it is urgent to upgrade the WWTP.By directly returning the sludge of sedimentation tank and mixing the nitrification liquid of aerobic tank into the regulating tank,denitrification and bacterial culture acclimation are carried out by making full use of the space of the regulating tank and the high quality carbon source in wastewater.The results show that the average concentration of TN in effluent decreased from 41.50 mg/L to 17.89 mg/L after modification.The average CODCr concentration decreases from 187.50 mg/L to 48.55 mg/L.It is found that the reflux of sludge and nitrification liquid make the regulating tank play a good role in denitrification and nitrogen removal.The TN of the effluent from the regulating tank is reduced from 95.6 mg/L to 47.5 mg/L,which lays a foundation for the denitrification efficiency of the whole section.In addition,due to the improvement of sludge performance,the sludge discharge volume of WWTP is reduced by 80％compared with that before the transformation,the use of reagent is greatly reduced,and the interval of sand filter backwashing is extended by 300％,which saves operating costs for enterprises.In conclusion,it is a cost-effective method to improve the denitrification capacity of the regulating tank in AO process by reflux design,which provides a certain reference for the future upgrading and potential transformation of the same type of process.关键词
AO改造/脱氮/调节池/污泥回流/污水处理站/污泥减量Key words
AO transformation/denitrification/regulating tank/sludge reflux/wastewater treatment plants(WWTPs)/sludge reduction分类
建筑与水利
