污水处理厂同步化学除磷对生物除磷的影响

Effect of simultaneous chemical phosphorus removal on biological phosphorus removal in WWTPs

为满足不断提高的污水处理排放标准要求,化学除磷工艺被越来越广泛地应用,其中同步化学除磷(Simultaneous chemical phosphorus removal,SCPR)是运行较为简单、投资较少的工艺。以两座采用SCPR工艺的污水处理厂为研究对象,进行了系统性的水质检测与分析,探究了SCPR对生物除磷的影响及其机理。研究结果表明,协同除磷时,除磷药剂的过量投加导致外回流污泥含有大量的残余除磷药剂。当外部条件满足聚磷菌释磷环境时,回流污泥中的残余除磷药剂对厌氧释磷过程无明显影响。但回流污泥中的残余除磷药剂可瞬间与进水TP及聚磷菌在厌氧期释放的磷反应,使得进入好氧区的TP浓度较低,好氧吸磷作用不能发挥或作用降低,同时除磷药剂的过量投加导致运行费增加。建议设置精准加药系统,根据好氧出水实时TP浓度确定除磷药剂投加量,既可减少药耗,又可同时发挥生物除磷最大潜力,有利于SCPR工艺的高效运行。

To meet the ever-increasing requirements of wastewater treatment discharge standards,chemical phosphorus removal processes have been increasingly widely used,among which simultaneous chemical phosphorus removal(SCPR)is the simplest to operate and the least invested process.In this study,two wastewater treatment plants using the SCPR process were used as research objects,and systematic water quality tests and analyses were conducted to investigate the effects of SCPR on biological phosphorus removal and its mechanism.The results showed that the overdosing of phosphorus removal chemicals during synergistic phosphorus removal resulted in the outflow sludge containing a large amount of residual phosphorus removal chemicals.The residual phosphorus removal chemicals in the return sludge had no significant effect on the anaerobic phosphorus release process when the external conditions met the environmental factors required for phosphorus release by phosphorus accumulating organisms(PAOs).However,the residual phosphorus removal chemicals in the return sludge can instantly react with the influent TP and phosphorus released by the PAOs in the anaerobic phase,so the concentration of TP entering the aerobic zone is low,and the aerobic phosphorus absorption effect cannot be exerted or the effect is reduced,resulting in an increase in the cost of phosphorus removal chemicals during operation.It is recommended to set up aprecise dosing system,according to the real-time TP concentration of aerobic effluent to determine the dosage of phosphorus removing chemicals,which can reduce the consumption of drugs,and at the same time give full play to the maximum potential of biological phosphorus removal,which is conducive to the efficient operation of the SCPR process.