磷酸铵镁沉淀法回收污水中磷的反应条件优化

A reaction condition optimization for phosphorus removal from wastewater by magnesium ammonium phosphate sedimentation

用磷酸铵镁沉淀法(MAP)进行污水处理厂污泥脱水上清液等含磷废水的处理是目前最具有前景的实现除磷及磷回收途径之一。模拟污水厂富磷液水质,以MAP法进行了可溶性磷回收试验研究。通过正交试验确定了MAP沉淀反应影响因素的次序依次是:pH值、氮磷比、镁磷比和反应时间。通过单因素试验进一步对反应工艺条件进行了优化,得到最优反应条件:pH值为10、n(Mg)/n(P)为1.5∶1、反应时间20 min,氮与磷的量比超过理论值1∶1时无需考虑氮源对MAP法磷回收率的影响。在相同的最佳反应条件下,模拟废水的磷回收率可达97.33%,污泥脱水上清液中磷回收率可达到80%左右。

Using magnesium ammonium phosphate （MAP） sedimentation process to treat supernatant liquid from sludge dehydration in wastewater treatment plant and some other phosphorus containing wastewater is one of the most prospective paths for the realization of phosphorus removal and recovery at present. A test that reclaimed dissoluble phosphorus from simulant P-rich water in wastewater treatment plant by MAP process was carried out and studied. The principal orders of factors which affect MAP sedimentation process concluded by orthogonal experiment are as follows： pH value, nitrogen-phosphorus ratio, magnesium-phosphorus ratio, and reaction time. Through the single factor experiment, the process condtition for the reaction was further optimized, and the optimal condition was determined finally, that was： pH value was 10, n（Mg）/n（P） was 1.5 ： 1, reaction time was 20 nfin, when the N-P ratio exceed the theoretic value 1 ： 1, the influence of nitrogen source on MAP recoverying phosphorus could be ignored. Under the same optimal reaction condition, the phosphorus recovery rate of the simulant wastewater and the supernatant liquid of sludge dehydration reached 97.33%, and about 80% respectively.