应用钙法除磷-碱解-微电解组合工艺预处理吡虫啉农药废水

Pretreatment of imidacloprid pesticide wastewater by a combined process of dephosphorization with calcium and alkaline hydrolysis & micro-electrolysis

根据吡虫啉农药废水成分复杂，含有大量有毒有害物质的特点，在小试实验研究的基础上，确定了预处理的组合工艺流程为：钙法除磷-碱解-催化微电解。实验结果表明，预处理的适宜参数为：钙法除磷的pH值11，搅拌速度为100r／min，钙的投加量为理论计算值的1．4倍；碱解反应的温度70℃，pH值11，反应时间2h；催化微电解反应的pH值3～4，曝气时间3h，催化剂与铸铁屑的质量比1：5。组合工艺对COD、色度、磷的总去除率分别达到81％、90％和99．99％，废水的可生化性能得到很大改善。组合工艺不仅适用于预处理高浓度吡虫啉农药废水，也能为其他高浓度、难生物降解农药废水的治理提供有益的参考。

An efficient combined pretreatment process , dephosphorization with calcium followed by alkaline hydrolysis and micro-electrolysis, was developed through lab-scale to treat the imidacloprid pesticide wastewater corresponding to its toxic and refractory nature. The experimental results show that the removal rates of COD and phosphorus are above 80% and 99.99% , respectively. The results of experiments show that the optimal conditions are ： lime dosage 1.4 times of the theoretical value, pH 11, mixing rate 100 r/min ; micro-electrolysis aeration time 3 h, pH 3 - 4 ; alkaline hydrolysis temperature 70 ℃ , pH 11 and reaction time 2 h. The biodegradability of the wastewater was improved evidently. This new process is not only applicable to treating high-concentration imidaeloprid pesticide wastewater, but also provides instructive example for efficient treatment of other refractory organic wastewaters.