In order to deal with the problem that the high total phosphorus (TP) concentration of effluent from one municipal wastewater treatment plant in Beijing,using the biological process(A2O) followed with chemical phosphorus removal process,laboratory tests and technical scale experiments were conducted in order. The aerobic tank effluent was sampled for evaluating the phosphorus removal efficiency of PAC, PFS, FeCl3 respectively, and the phosphorus removal mechanisms of the three reagents were further discussed. Phosphorus removal efficiency of PAC was the best among three coagulants. The TP concentration of effluent could be lower than 0.5mg/L and the coagulant cost was 0.078Yuan/t with the dosage of 60mg/L and the coefficientβof 4.15. The aerobic tank outlet was selected to be the dosing position for the technical scale experiments. Results showed that demand in phosphorus removal efficiency could be met with a PAC dosage of 60mg/L and coefficientβof 4.15. Considering the water quality and loading fluctuation, in order to ensure TP concentration of effluent discharged lower than 0.5mg/L, a detailed optimization scheme was proposed, through taking effective measures of improving the biological phosphorus removal and dosing the coagulants with feedback control methods to decrease the dosage amount of PAC,therefore reduced the operation cost and chemical sludge amount.%为有效解决北京某城市污水处理厂出水总磷含量较高的实际问题,通过在生物处理工艺(A2O)后端添加化学除磷强化单元的方法,依次开展了实验室试验和现场的生产性试验.实验室试验以好氧池出水为试验用水,对不同浓度梯度的聚合氯化铝(PAC)、聚合硫酸铁(PFS)、三氯化铁(FeCl3)等除磷效果进行了对比研究,并分别对其除磷机理进行了深入的探讨.试验结果表明：3种药剂中,PAC除磷效果最好,当其投加量为60mg/L,投加系数β为4.15时,出水总磷含量可小于0.5mg/L,而且药剂投加成本较低,仅为0.078元/t.现场生产性试验选取好氧池出水端为药剂投加点,对PAC的除磷效果进行现场验证.经试验测定,当PAC投加量为60mg/L,投加系数β为4.22时,污水处理厂出水总磷含量远低于0.5mg/L,符合排放要求.考虑到进水量和负荷的波动,在保证出水达标排放的前提下,为保证药剂的有效利用,通过采取针对性措施提高前端生物除磷效率及反馈投加药剂的方法,以有效减少药剂的投加量及化学污泥的排放量,达到节能减排的目的.
展开▼
