MFPAC混凝沉淀-矿化垃圾吸附预处理垃圾渗滤液

采用化学还原法制备纳米四氧化三铁，与聚合氯化铝（PAC）制备MFPAC磁性混凝剂，利用混凝沉淀-矿化垃圾吸附预处理垃圾渗滤液，用单因素变量法确定实验的最佳运行参数。结果表明：MFPAC磁性混凝剂对COD和色度的去除效果优于单独投加混凝剂PAC，在纳米四氧化三铁与PAC的质量比为1：3、MFPAC的投加量为1.5 g·L-1、搅拌条件为转速为300 r·min-1下搅拌60 s、溶液pH值为7.5（垃圾渗滤液原水的pH值）、絮凝时间为30 min的最佳运行条件下，COD由5 810 mg·L-1降低到2 173 mg·L-1，色度由1 658倍降低到556倍，其COD去除率为62.6%，色度去除率为66.5%；利用矿化垃圾作为吸附剂处理MFPAC混凝处理后的出水，在矿化垃圾粒径小于2 mm、焙烧温度为700℃、吸附剂投加量为40 mg·L-1、pH值为9的最佳条件下，经过12 h的处理，COD和氨氮的去除率分别为56.7%和68.4%，最终出水的COD和氨氮的浓度分别为941 mg·L-1和343 mg·L-1；最终，MFPAC混凝沉淀-矿化垃圾吸附工艺对垃圾渗滤液COD、色度和氨氮的去除率分别为83.8%、78.5%和74.3%。

MFPAC coagulation and aged refuse adsorption pretreatment of landfill leachate

Fe3O4 nanoparticles were prepared by a chemical reduction method and then, along with polyferric chloride (PFC), used to produce a composite coagulant, MFPAC. Experiments investigating the pretreatment of landfill leachate were conducted using the combined coagulation process and aged-refuse adsorption process. The optimum working conditions of the combined process were determined by a single factor method. The results indicated that MFPAC offered a higher coagulation efficiency than PAC, with COD and color removals of 62.6% and 66.5%, respectively. The optimum working conditions for the coagulation process were as follows:Fe3O4/PAC mass ratio of 1:3, MFPAC dosage of 1.5 g·L-1, stirring speed of 300 r·min-1, stirring time of 60 s, coagulation time of 30 min, and pH of 7.5. Under these conditions, the COD decreased from 5 810 to 2 173 mg·L-1, and the color declined from 1 658 to 556 times. The effluent of the coagulation process was further treated by an aged-refuse adsorption process. The optimum working conditions of the adsorption process were as follows:aged refuse particle size of less than 2 mm, 700℃roasting temperature, 40 mg·L-1 adsorbent, and pH 9. In the adsorption process, the COD and ammonia nitrogen removals reached 56.7% and 68.4%, respectively, after treatment for 12 h. The COD and ammonia concentrations decreased to 941 mg·L-1 and 343 mg·L-1 in the final effluent. By combining MFPAC coagulation with aged refuse adsorption, the COD, color, and ammonia nitrogen reduction could be increased to 83.8%, 78.5%, and 74.3%, respectively.