Abstract: Since the wastewater from dairy farms contains high concentration of organics, wastewater must be treated to meet the requirements of related discharge standards. In order to reduce environment pollution caused by wastewater from dairy farms located at the suburb of Beijing, this paper designed a pretreatment experiment at bench-scale to optimize the operational parameters of chemical flocculation. Poly aluminum chloride (PAC) and 3 types of ionic polyacrylamide (PAM) were used as flocculants, and 2 flocculation trials were conducted and compared. The results showed that the effect of PAM was better than that of PAC and PAM combination. As for PAM adding, the ionic types of PAM took a role in the flocculation effects (P＜0.05). The best flocculation effect was observed in adding 2.5 mL NPAM at the dosage of 1 g/L. In such case, the concentrations of COD, NH+4-N and total phosphorus in supernatant were (12 892±2 354) mg/L, (462±53) mg/L and (31±3) mg/L, and the removal rates were 69.48%±4.10%, 13.11%±8.59% and 85.05%±1.27%, respectively. Moreover, it cost only 0.05 yuan/m3. Therefore, it was feasible to pretreat the dairy farm wastewater with non-ionic polyacrylamide, thus easily reducing organics and suspending solid in the wastewater. This study  provided a scientific basis for the application of flocculation on wastewater with high concentration pollutants from dairy cattle farm.

Key words: dairy farm, wastewater, flocculation, poly aluminum chloride, polyacrylamide

摘要： 为了解决奶牛场高浓度污水深度处理难度大的问题，开展了化学絮凝预处理效果研究的试验。选用聚合氯化铝（PAC）和3种离子型的聚丙烯酰胺（PAM）作为絮凝剂，通过对絮凝处理后上清液体积、化学需氧量（COD）和浊度的检测和分析，比较了PAM单独使用以及PAC与PAM复合使用的絮凝效果。结果表明：单独投加PAM比PAC与PAM复合使用的处理效果好，且PAM的离子型对高浓度奶牛场污水处理中COD和浊度的去除率有显著影响。当非离子型聚丙烯酰胺的浓度为1 g/L、投加量为2.5 mL时处理效果最好，出水的COD、氨氮质量浓度和总磷质量浓度分别为（12 892±2 354）mg/L、（462±53）mg/L和（31±3）mg/L，相应的去除率分别可达69.48%±4.10%、13.11%±8.59%和85.05%±1.27%，此时的经济成本为0.05元/m3。采用非离子型聚丙烯酰胺对高浓度奶牛场污水进行预处理是可行的，能够有效降低奶牛场污水中的有机物和悬浮物，减轻后续处理工艺的负荷，研究结果可为奶牛场高浓度污水化学絮凝预处理方法的应用提供科学依据。

关键词: 奶牛场, 污水, 絮凝, 聚合氯化铝, 聚丙烯酰胺