蚀刻液处理中超高浓度氨氮废水除氮工艺

Treatment technology of ultra-high concentration ammonia nitrogen wastewater during etching solution

为去除蚀刻液处理过程中废水残留超高浓度氨氮,配制3000 mg/L氨氮溶液模拟废水.采用鸟粪石沉淀法,研究了pH值、pH调节方式、药剂添加顺序以及n(N):n(Mg):n(P)对3组药剂脱氮效果的影响.结果表明,pH值恒定10.5,摩尔比为n(N):n(Mg):n(P)=1:1.4:1.2时,3组药剂除氮效率分别达98.64%(MgSO_(4)+NaH_(2)PO_(4))、97.73%(MgCl_(2)+Na_(2)HPO_(4))和85.69%(MgO+H_(3)PO_(4));药剂添加顺序对氨氮去除率影响较大;反应过程导致pH下降,因此仅调节废水初始pH值难以获得理想的除氮效果.实际生产废水验证结果表明,最优条件下,MgSO_(4)+NaH_(2)PO_(4)除氮效率能达95.5%.

In order to reduce the ultra-high concentration of ammonia nitrogen in the waste water during the etching solution treatment,3000 mg/L ammonia nitrogen solution was prepared to simulate the waste water by using the struvite precipitation method.The effects of pH value,pH regulation order,additive order and n(N)∶n(Mg)∶n(P)on the denitrification effect of the three groups of agents were studied.The results showed that the nitrogen removal efficiency of the three groups reached 98.64%(MgSO_(4)+NaH_(2)PO_(4)),97.73%(MgCl_(2)+Na_(2)HPO_(4))and 85.69%(MgO+H_(3)PO_(4))when the pH value was 10.5 and the molar ratio was n(N)∶n(Mg)∶n(P)=1∶1.4∶1.2.The order of adding agents has great influence on ammonia nitrogen removal rate.The reaction process leads to the decrease of pH,so it is difficult to get the ideal effect of nitrogen removal only by adjusting the initial pH value of wastewater.The verification results of the actual production wastewater showed that the nitrogen removal efficiency of(MgSO_(4)+NaH_(2)PO_(4))could reach 95.5%under the optimal conditions.