城市污水处理厂协同沉淀除磷与后续混凝除磷对比实验研究

Comparative Study on Synergism Sedimentation and Subsequent Coagulating Sedimentation Phosphorus Removal

在室温条件下,选用氯化铁、明矾、硫酸铝和聚合氯化铝（PAC）4种常见混凝剂,对城市污水处理厂氧化沟出水和二沉池出水进行协同沉淀和后续混凝除磷对比实验;协同沉淀实验的混凝剂投药量为0～40m g/L,pH值为2.36～10.09;后续混凝除磷实验的混凝剂投药量为0～100m g/L,pH值为2.31～10.07。结果表明,协同沉淀除磷时,PAC、明矾、氯化铁以及硫酸铝的适宜投药量分别为15m g/L、20m g/L、30m g/L和25m g/L,pH值适宜范围分别为6.79～8.32、5.82～8.32、6.79～6.92和6.79～6.92;后续混凝除磷时,PAC、明矾、氯化铁以及硫酸铝的适宜投药量分别为30m g/L、70m g/L、50m g/L和40m g/L,pH值适宜范围分别为5.92～10.07、6.92～8.08、6.92～10.07和6.92～8.08。在4种混凝剂中,PAC能够在较小投药量条件下有效地降低出水中的总磷含量,优于其他3种混凝剂的处理效果;在实现相同除磷效果的条件下,后续混凝除磷工艺所需投药量为协同沉淀工艺的1.6～3.5倍,因此建议采用PAC混凝剂和协同沉淀工艺进行总磷去除处理,pH值保持在中性范围内。

In this paper,effluent of oxidation channel and secondary sedimentation tank are treated by coagulation sedimentation method with four kinds of coagulant agents,i.e.,FeCl3,Potash Alum,Al2（SO4）3 and polyaluminum chloride（PAC）,respectively.The coagulant dosage range of synergism sedimentation experiment is from 0 to 40mg/L,and the pH is between 2.36 and 10.09.The coagulant dosage range of subsequent coagulating sedimentation experiment is between 0 and 100mg/L and the pH is between 2.31 and 10.07.The result shows that the suitable four kinds of coagulant dosages of PAC,Potash Alum,FeCl3,Al2（SO4）3 are 15mg/L,20mg/L,30mg/L,25mg/L,and the pH scope are 6.79～8.32,5.82～8.32,6.79～6.92,6.79～6.92,respectively.The suitable four kinds of coagulant dosages in subsequent coagulating sedimentation experiment are 30mg/L,70mg/L,50mg/L,40mg/L,and the pH scope are 5.92～10.07,6.92～8.08,6.92～10.07,6.92～8.08,respectively.PAC is better than the other three kinds of coagulant agent due to its small dosage and high efficiency.Furthermore,the coagulant dosage of subsequent coagulating experiment is about 1.6 to 3.5 times as what is in the synergism sedimentation experiment.So PAC and synergism sedimentation method is suitable to be used for phosphorus removal in neutral condition.