钙镁复配药剂对污水的除磷脱氮作用

Removal of phosphorus and nitrogen from sewage by calcium and magnesium compounding agent

针对高氮磷含量污水处理,以钙镁合剂利用化学沉淀法对滤液进行除磷脱氮实验。分析钙镁合剂除磷脱氮的机制,考察NaOH投加量和钙镁药剂复配投加量的影响,得到最佳工艺条件。结果表明:实验中NaOH、MgCl_2和CaCl_2的质量浓度分别为150、60和40 mg/L时,污水中总磷(TP)去除率达到90%,总氮(TN)和NH_3-N去除率达到25%;动态小试试验中选取NaOH、MgCl_2和CaCl_2的质量浓度分别为105、48和24 mg/L时,TP去除率达到90%,TN和NH_3-N去除率达到30%;Ca^(2+)和Mg^(2+)在一定条件下与PO^-_4、NH^+_4等基团发生反应,生成磷酸铵镁以及羟基磷酸钙沉淀,从而达到除磷脱氮效果。

Calcium-magnesium mixture agent was used for treating sewage with high nitrogen and phosphorus content, and phosphorus and nitrogen removal experiments were carried out. The mechanism of denitrification and phosphorus removal by calcium and magnesium compound was analyzed. And the dosages of NaOH and calcium and magnesium mixture agent were investigated, through which the optimized conditions were obtained. It is found when the mass concentration of NaOH, MgCl2 and CaCl2 is 150 mg/L, 60 mg/L, and 40 mg/L respectively, the removal rate of total phosphorus(TP), total nitrogen TN and NH3-N reaches 90% and 25% after treatment. In the dynamic test, when the mass concentrations of NaOH, MgCl2 and CaCl2 is 105 mg/L and 48 mg/L, and 24 mg/L respectively, the removal rate of TP reaches 90% and the removal rate of TN and NH3-N is 30%. When Ca^2+ and Mg^2+ react with PO4^-, NH4^+ and other groups to form magnesium-ammonium-phosphate and hydroxyapatite precipitation, the phosphorus and the nitrogen in the sewage can be removed.