溶气气浮工艺用于城镇污水处理厂二级出水的深度除磷研究

STUDY ON DEEP DEPHOSPHORIZATION OF EFFLUENT FROM URBAN SEWAGE TREATMENT PLANT BY DISSOLVED AIR FLOATATION PROCESS

以江苏省某城镇污水处理厂二级出水为研究对象,通过模拟试验及混凝+气浮深度除磷中试,探索了气浮工艺取代过滤工艺的深度除磷效果。结果表明:FeCl3的除磷效果最优,投加量为5 mg/L时可将出水ρ(TP)降至0.2 mg/L,投加量为15 mg/L时可将出水ρ(TP)降至0.05mg/L;气浮工艺对PAM的依赖性较强,需通过投加PAM保证水质达标稳定性和达到除磷效果(ρ(TP)<0.05 mg/L),PAM投加浓度为0.6 mg/L;溶气压力与回流比相关,当回流比为20%、溶气压力为0.6 MPa左右时,装置运行效果稳定;将污水中磷组分分为TP、STP、PO43--P和不可混凝磷组分,通过对进出水磷组分分析,表明气浮工艺对悬浮态TP和磷酸盐去除效果较好,对不可混凝磷组分无去除效果。

In this paper,the secondary effluent of a municipal sewage treatment plant in Jiangsu Province was taken as the research object. Through the simulation test and the pilot test of coagulation+air flotation deep phosphorus removal,the deep phosphorus removal effect of air flotation process instead of filtration process was explored. The results showed that FeCl3 had the best phosphorus removal effect. When the molar ratio was 2. 3,the TP of effluent could be reduced to 0. 2 mg/L,and when the molar ratio was 7,the TP of effluent could be reduced to 0. 05 mg/L;the process of air flotation had a strong dependence on PAM,so it was necessary to add PAM to ensure the effect of phosphorus removal and the stability of water quality up to standard. The concentration of PAM was 0. 6 mg/L;when the reflux ratio was 20% and the dissolved gas pressure was about 0. 6 MPa,the operation effect of the device was stable;through the analysis on the phosphorus components,it was found that the air floatation process had a good effect on the removal of suspended TP and phosphate,but no effect on the removal of noncoagulable phosphorus components.