混凝-超滤工艺处理饮用水厂滤池反冲洗水和排泥水的效能

为探究饮用水厂滤池反冲洗水和排泥水的直接回用和处理后回用对水厂的影响及两类水处理过程中的差异，采用了污染负荷计算、实验室混凝小试和现场混凝-超滤中试装置对两类生产废水分别进行了研究。溶解性有机碳(dissolved organic carbon，DOC)、氨氮 (NH₄⁺-N)、Al³⁺和全氟类化合物(perfluorinated compounds，PFASs)的污染负荷计算结果表明生产废水直接回用会为水厂带来一定的额外负荷，其中排泥水和反冲洗水分别对PFASs和Al³⁺负荷贡献较大；通过对小试中浊度，UV₂₅₄以及5种荧光组分去除效果的对比，反冲洗水的混凝效果稍好于排泥水，同时10 mg·L⁻¹的聚合氯化铝为最佳混凝剂方案；在中试过程中，两类水中的浊度、有机物、Al³⁺和PFASs均可被有效去除，出水差异较小，但反冲洗水中的亲水性和小分子有机物使得其去除效果低于排泥水。总体来说，经过处理之后，两类生产废水均可回用，回用可有效减少废水排放量，提高水厂水资源利用率。

Efficacy of coagulation-ultrafiltration treatment for filter backwash water and sedimentation sludge water from drinking water treatment plants

To investigate the impacts of direct reuse and treated reuse of filter backwash water and sedimentation sludge water on water treatment plants, as well as the different performance in the treatment processes of these two types of water, this study employed pollution load calculations, laboratory-scale coagulation experiments, and pilot-scale coagulation-ultrafiltration trials to examine the two types of production wastewater. The pollution load calculations for dissolved organic carbon (DOC), ammonia nitrogen (NH4+-N), Al3+, and perfluorinated compounds (PFASs) indicated that the direct reuse of production wastewater would impose an additional pollution load on the drinking water treatment plants, of which sedimentation sludge water and filter backwash water contributed significantly to the load of PFASs and Al3+, respectively. Comparative analysis of turbidity, UV254, and PFASs removal in the laboratory-scale tests revealed that the coagulation performance of filter backwash water was slightly better than that of sludge discharge water. A dosage of 10 mg·L−1 of poly-aluminum chloride was found to be the optimal coagulant. In the pilot-scale experiments, turbidity, DOC, Al3+, and PFASs in both types of water were effectively removed, with small differences in effluent quality. However, the presence of hydrophilic and small-molecule organic matter in filter backwash water resulted in lower removal efficiency compared to sedimentation sludge water. Overall, after appropriate treatment, both the two wastewater types can be reused, thereby reducing wastewater discharge and improving water resource utilization in drinking water treatment plants.