苦土处理氮磷废水的研究

Treatment of nitrogen and phosphorus from wastewaters by magnesia

采用苦土为沉淀剂对模拟氮磷废水和实际氮磷废水进行了脱氮除磷实验研究,探讨了苦土投加量、pH及反应时间对废水中氮磷去除率的影响。此外,对苦土处理氮磷废水的动力学进行了研究,并对苦土及反应沉淀物进行了XRD分析。结果表明,以苦土为沉淀剂,处理氨氮浓度为200 mg/L的模拟废水的最佳条件为:苦土与氨氮(NH4+-N)的质量比为25∶1,平衡时间10 min,氨氮去除率可达到93%,磷去除率达到99%。用苦土为沉淀剂处理南京某厂的实际氮磷废水(氨氮浓度为590 mg/L,磷浓度为1 630 mg/L),氨氮的去除率达到92%,磷的去除率达到99%。苦土处理氮磷废水的动力学数据符合二级动力学模型,主要以化学反应为主。处理后废水中沉淀物的XRD分析表明其主要成分为磷酸铵镁,进一步证明苦土处理氮磷废水主要以化学反应为主。

Removing nitrogen and phosphorus from simulated and actual wastewaters by magnesia was carried out.Some factors affecting the removal efficiency of nitrogen and phosphorus were discussed,including the dosage of magnesia,pH,and the reaction time.In addition,the dynamics of the process was studied as well.Meanwhile,the magnesia and the products of the process were analyzed by XRD.The results show that the optimal technological conditions for the removal of nitrogen and phosphorus from wastewater（200 mg/L nitrogen） were： mass ratio of magnesia and nitrogen of 25∶1;balance time of 10 min,the removal rate of ammonia nitrogen and phosphorus reached to 93% and 99%,respectively.For the actual wastewater（590 mg/L ammonia and nitrogen,1 630 mg/L phosphorus） in Nanjing,the removal rate of ammonia nitrogen and phosphorus reached to 92% and 99%,respectively.The dynamic data could be described by the pseudo second-order model,implying a chemical reaction.The XRD analysis indicates that the major component of the precipitation is NH4MgPO4,which demonstrates further a chemical reaction.