养猪场废水的化学混凝后处理

养猪场废水经曝气－解－两段接触好氧处理后，氨氮、悬浮物、色度、ＰＨ值都达到了排放标准，但是ＣＯＤｃｒ未达排放标准，采用混凝剂聚合硫酸铁、聚合氯化铝对废水进行混凝试验比较，结果表明采用聚铝的最适ＰＨ选择ＰＨ６．５为宜，最佳投药量为２００ｍｇ／Ｌ；对于混凝剂聚铁采用ＰＨ４．５－５．７范围较好，其最佳投加量为２５０ｍｇ／Ｌ。以聚铁作混凝剂的出水的ＰＨ值偏酸性，需在出水中加少量碱液中和，同时由于用聚铁作混

POST - TREATMENT OF CHEMICAL COAGULATION IN PIGGERY WASTEWATER

Through bubbling - hydrolysis two stage contact oxidation treatment, NH_4-N, suspending substances, color grade, and pH value of piggery wastewater met the National Discharge Standard of China with COD_(cr) being an except. The results of coagulating treatments of polyaluminumchloride and polyferrosulphate as coagulants demonstrated that the most suitable pH values were 6.5 and 4.5 - 5. 7, and the optimum adding amounts were 200mg/L and 250mg/L, for polyaluminumchloride and polyferrosulphate respectively. The out - water with polyferrosulphate as coagulant, tends to be acid, and thus needs to be neutralized by adding small amount of lye, and was meanwhile often yellow. Therefore adapting polyaluminmchloride as coagulant seems to be a economically practical method of piggery wastewater treatment. With polyaluminumchloride as coagulating treatment, the final out - water reached a COD(cr) of 78 - 95 mg/L and color grade of < 50, and the other indices met the National Standard.