微电解-芬顿法预处理吡虫啉农药生产废水

Pretreatment of imidacloprid pesticide wastewater by microelectrolysis-fenton process

吡虫啉农药生产废水是一种典型的高浓度难降解有机废水，可生化性差，需采用物化法进行预处理。采用微电解-芬顿法作为吡虫啉农药生产废水的主要预处理工艺，有效地降低了废水中有机物浓度，提高了废水预处理出水的可生化性。实验结果表明，微电解最佳条件：pH3-4，停留时间90min；芬顿法的最佳条件：微电解出水调pH4-5，控制停留时间1h，30％H2O2按140mg／L的比例投加，最终预处理出水的COD去除率为81％，色度的去除率达90％，BOD5／COD提高到0.25以上，废水可生化性大大提高。

Midacloprid pesticide wastewater is a typical organic wastewater. With high concentration of some kinds of persistent organic pollutants, it is difficult to be directly degraded by bio-treatment, and needs to be pre-treated by some physic-chemical processes. Microelectrolysis method and microelectrolysis-Fenton method, microelectrolysis enhanced by addition with H202, were investigated for the pesticide wastewater pretreatment, respectively. The optimal conditions of the pretreatment were determined as follows： pH 3-4 and reaction time 90 min for micro-e-lectrolysis method, while the dosage of H2O2 140 mg/L, pH 4-5, and reaction time 60 min for the microelectroly-sis-Fenton method. Under the above-mentioned conditions for the microelectrolysis-Fenton method, about 81% and 90% removal were obtained for COD and chroma, respectively. Furthermore, the value of BOD5/COD was found to be increased above 0.25, which implied the biodegradability for the wastewater was improved evidently.