矿渣制备的无机复合絮凝剂在城市污水深度除磷中的应用

以制铝矿渣及铝土矿制备的无机复合絮凝剂进行污水深度除磷研究。在模拟废水条件下,确定了自制絮凝剂除磷的最佳pH为8、最佳投加量0.08 g/L及最佳水力条件(快速搅拌30 s、转速200 r/min;慢速搅拌15 min、转速20 r/min);然后将其用于处理生活污水站二级出水,TP、TN、COD、NH3-N和浊度去除率分别为94.69%、62.78%、78.93%、47.94%和89.30%,优于《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级B标准,自制絮凝剂除磷效果优于常用市售絮凝剂PAC(TP去除率91.73%);自制絮凝剂的除磷机理主要以沉淀和电性中和作用为主,以吸附架桥和网捕卷扫作用为辅。

Inorganic composite flocculant prepared from slag and its application in advanced phosphorus removal of municipal sewage

In this study, a novel inorganic composite flocculant was prepared from low-grade aluminum slag and bauxite, and the advanced removal of phosphorus from wastewater by this flocculant was investigated. The optimal pH value and dosage for the phosphorus removal from simulated wastewater by this flocculant were 8 and 0.08 g/L, respectively, and the optimum hydraulic condition was as follows: rapid stirring for 30 s at 200 r/min; slow stirring for 15 min at 20 r/min. The prepared flocculant was then used in the treatment of secondary effluent from sewage treatment plant, and the removal efficiencies of TP, TN, COD, NH₃-N, turbidity were 94.69%, 62.78%, 78.93%, 47.94%, 89.30%, respectively and met the first level B class criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002). The removal efficiency of TP was significantly higher than that of conventional flocculant PAC (91.73%). The mechanisms of phosphorus removal by the prepared flocculant are mainly precipitation and electrical neutralization, supplemented by bridging absorption and sweep netting.