磷酸铵镁沉淀法处理氨氮废水及沉淀剂的回用  

Treatment of Ammonia Nitrogen Wastewater by Magnesium Ammonium Phosphate Precipitation Process and Recycling of Precipitant

作　　者：陈徉[1] 陈英文[1] 彭慧[1] 沈树宝[1] 

机构地区：[1]南京工业大学制药与生命科学学院,江苏南京210009

出　　处：《化工环保》2008年第1期16-19,共4页Environmental Protection of Chemical Industry

基　　金："十一五"国家"863"项目(2006AA022211);江苏省省级污染防治专项资金(2006-1-W-19);江苏省自然科学基金(BK2006181;BK2007188)。

摘　　要：用磷酸铵镁沉淀法处理氨氮废水,在pH为8.5、反应时间为20 min、n(PO_4^(3-)):n(Mg^(2+):n(NH_4^+)= 1.2:1.1:1的最佳条件下,氨氮去除率为97.6%。采用加入足量饱和Ca(OH)_2溶液的方法,可使上层清液中多余的Mg^(2+)与PO_4^(3-)形成Mg(OH)_2和Ca_3(PO_4)_2沉淀,离心后再用浓硫酸溶解,可达到回用的目的,而处理后上层清液中剩余磷酸盐质量浓度低于1 mg/L,达到GB 8978—1996《污水综合排放标准》中第二类污染物国家二级排放标准的要求。所得MgNH_4PO_4沉淀用加热碱溶方法回用,MgNH_4PO_4沉淀的回用次数小于6时,氨氮去除率在80%左右;所得MgNH_4PO_4沉淀用加酸溶解方法回用,氨氮去除率最高为35%。Ammonia nitrogen wastewater was treated by precipitation process with magnesium ammonium phosphate as precipitant. Under the optimum conditions of pH 8.5, reaction time 20 min andn（PO4^3-） ： n （Mg^2 ＋） ： n（NH4^＋） =1.2 ： 1. 1 ： 1, the removal rate of ammonia nitrogen is 97.6%. The redundant Mg^2＋ and PO4^3- in the supematant can be reused by adding Ca（OH） 2 saturated solution to form Mg（ OH）2 and Ca3 （PO4）2 precipitates and then dissolving the precipitates with oil of vitriol after centrifugation. The mass concentration of phosphate remained in the supematant is below 1 mg/L, which can meet the second grade of national standard GB 8978-1996. The precipitate MgNH4PO4 can be recycled by adding alkali and heating with about 80% of ammonia nitrogen removal rate when it is recycled less than 6 times. The precipitate MgNH4PO4 can be recycled also by adding acid with 35 % of the highest ammonia nitrogen removal rate.

关 键 词：氨氮 化学沉淀法 磷酸铵镁 回用 

分 类 号：X703.1[环境科学与工程—环境工程]