基于磷容量的污水处理厂除磷效能提升控制技术研究

Research on phosphorus removal efficiency improvement control technology of sewage treatment plant based on phosphorus storage capacity

针对污水处理厂回流污泥除磷能力无法准确表征以及除磷药剂使用效率低的问题,首次建立了污泥磷容量的检测方法,研究了除磷药剂种类及用量对污泥磷容量的影响,同时开展了除磷药剂效能提升研究工作。结果表明,使用化学除磷工艺的污水处理厂污泥有不同程度的磷去除能力,即“磷容量”,通过现场实测及拟合计算得到污水处理厂磷容量为0.32~3.25 mg/g(以单位污泥混合液悬浮固体的溶解态活性磷酸盐(sRP)去除量计),折合除磷药剂投加量为0~15.85 mg/L。除磷药剂种类与投加量是影响回流污泥磷容量的关键因素,相同投加量水平下,投加硫酸铝的污泥磷容量较投加聚合氯化铝(PAC)的污泥磷容量高,除磷药剂的预水解程度是导致磷容量差异的主要原因。污泥磷容量与除磷药剂投加量呈正相关。基于污泥磷容量的检测结果,污水处理厂可以采用改变污泥外回流比或将剩余污泥回流到初沉池的方式提高除磷药剂使用效率,可使进水的sRP下降10%以上。此外,剩余污泥回流初沉池可以减少30%的污泥排放量,既强化了除磷效果又实现了污泥的减量化,对污水处理厂绿色发展具有非常重要的指导意义。

A detection method for sludge phosphorus storage capacity was firstly established to address the problems of inaccurate characterization of the phosphorus removal capability of sewage treatment plant return sludge and low efficiency of phosphorus removal agents.The effects of phosphorus removal agent types and dosages on sludge phosphorus storage capacity were investigated,and how to improve the efficiency of phosphorus removal agents was conducted.The results showed that the return sludge of sewage treatment plant using chemical phosphorus removal process had varying degrees of phosphorus removal efficiency,namely“phosphorus storage capacity”.Through on-site measurement and fitting calculation,the sludge phosphorus storage capacity was determined to be 0.32-3.25 mg/g(calculated by the removal of soluble reactive phosphorus(sRP)per unit of sludge mixed liquor suspended solids),converting into the dosage of phosphorus removal agents was 0-15.85 mg/L.The type and dosage of residual phosphorus removal agent were key factors affecting the sludge phosphorus storage capacity.At the same addition amount,aluminum sulfate could achieved higher sludge phosphorus capacity than PAC.The pre-hydrolysis degree of the agent was the main reason for the difference in phosphorus storage capacity,and the phosphorus storage capacity of the sludge was positively correlated with the dosage of the phosphorus removal agent.Based on the detection results of sludge phosphorus storage capacity,the sewage treatment plant could improve the efficiency of phosphorus removal agent usage by changing the external sludge return ratio or returning the remaining sludge to the primary settling tank,which could decrease the influent sRP by more than 10%.In addition,returning the remaining sludge to the primary settling tank could reduce sludge emissions by 30%,which not only enhanced the phosphorus removal effect but also achieved sludge reduction,providing important guidance for the green development of sewage treatment plants.