磷酸铵镁结晶技术处理模拟氨氮废水

从工程应用角度出发,考察了不同氨氮起始浓度、反应温度、搅拌速率及搅拌时间对磷酸铵镁化学结晶技术沉氨效果的影响。研究结果表明,当氨氮起始浓度超过200 mg/L时,氨氮去除率达到90%以上。不同温度条件下,氨氮去除率超过80%。随着温度升高,氨氮去除率明显上升,最高可达90%以上。搅拌是晶粒生长的一个重要影响因素;搅拌速率对晶粒生长作用复杂,当搅拌速率低于150 r/min时,加速了晶粒生长,达2.25 nm;提高搅拌速率,晶粒大小降至1.54 nm。而搅拌时间对晶粒生长起着非常明显的促进作用;随着搅拌时间的延长,晶粒出现明显的增长,从5 min的0.47 nm长至120 min的1.71 nm。

Ammonium removal from simulated wastewater by struvite crystallization technology

The effects of initial concentration of ammonium, stirring speed, mixing time and reaction temperature on the removal of ammonium by magnesium ammonium phosphate precipitation were investigated from the aspect of engineering application. The results showed that the removal rate of ammonium was more than 90% when the initial concentration of ammonium was above 200 mg/L. An ammonium removal rate of more than 80% was achieved for all test temperatures, and the removal rate increased up to 90% with the increase of reaction temperature. As a key factor, stirring was observed to influence the grain growth in a complicated manner. A complicated effect of stirring speed on grain growth was found, a stirring speed lower than 150 rpm would accelerate the struvite crystal nucleation, with a grain size of 2.25 nm. The grain size decreased to 1.54 nm with the increase of stirring speed. Finally, the grain growth was significantly accelerated by extending the mixing time, from 0.47 nm (5min) to 1.71 nm (120 min).