无机超滤膜预处理垃圾填埋场渗滤液的过程参数分析

目的]对无机超滤膜的液体渗透性进行评价。方法]采用无机超滤膜对垃圾填埋场渗滤液进行预处理,重点探讨pH值、浓缩倍数、操作压差、膜面流速等过程参数对预处理效果和膜通量的影响。结果]较优的运行参数为:pH值宜处于中性偏酸的范围,6.5~7.0效果较佳;操作压差不宜超过0.4 MPa,一般选择为0.34 MPa,膜面流速为3.5~4.0 m/s。在该条件下,对COD、TOC、氨氮、TDS、FDS和浊度的去除率分别达到40.6%、51.2%、6.0%、19.3%、19.9%和70%。结论]渗滤液pH值的改变直接影响无机超滤膜表面的电性,从而与无机离子和腐殖酸共同作用,引起膜通量和去除率的变化。无机超滤膜通量随操作压差和膜面流速的增加而增大,但由于浓差极化和凝胶层的影响,存在临界压差和流速。

Analysis on Process Parameters of Pre-treating Leachate Landfill Site with Inorganic Ultrafiltration Membrane

Objective] The study aimed to evaluate liquid permeability of inorganic ultrafiltration membrane.Method] The leachate in landfill site was pre-treated by inorganic ultrafiltration membrane to discuss on the influences of process parameters such as pH value,concentration multiple,operation pressure and membrane flow velocity on pre-treatment effect and membrane flux.Result] The superior operation parameters were as follows: pH value was in the scope of acid of neutral,the effect was better when pH value was 6.5～7.0;the operation pressure was not suitable to exceed 0.4 MPa and generally chosen to be 0.34 MPa;the membrane flow velocity was 3.5～4.0 m/s.Under these conditions,the removal rates of COD,TOC,ammonia nitrogen,TDS,FDS and turbidity were 40.6%,51.2%,6.0%,19.3%,19.9% and 70% resp.Conclusion] The change of leachate pH value influenced the electrical property of inorganic ultrafiltration membrane surface,so as to act together with inorganic ion and humic acid to induce the change of membrane flux and removal rate.The inorganic ultrafiltration membrane flux increased along with operation pressure difference and membrane flow velocity increasing,but there existed critical pressure difference and flow velocity due to the influences of concentration polarization and gel layer.