陶瓷微滤膜在纳滤系统预处理的生产性试验

Productive Test of Ceramic MF Membrane for NF System Pretreatment

为了研究陶瓷膜(ceramic membrane,CM)作为纳滤系统预处理技术的可行性,选取4种不同孔径的CM(0.1、0.3、0.5、1.0μm),进行20 m^(3)/h规模的生产性试验。结果表明,不同孔径CM出水淤泥密度指数(silt density index,SDI)和修正污染指数(modified fouling index,MFI)相比试验原水有不同程度的降低,整体呈现膜孔径越小,出水SDI和MFI越低的趋势,且能满足纳滤进水SDI小于5、MFI小于10的要求。但4种孔径CM对有机物的去除率均低于10%,对无机盐离子的去除率也低于2%。膜孔径越小,清洗越频繁,不仅影响膜的产水量和纳滤系统的稳定性,且增加设备运行维护成本,综合比较,0.5μm CM膜通量下降相对较缓,清洗频率低,更适合作为纳滤系统的预处理工艺。

To investigate the feasibility of CM for nanofiltration systems pretreatment technology,four types of CM with different pore sizes(0.1,0.3,0.5,1.0 μm) were selected for a productive test at a scale of 20 m^(3)/h.Results showed that the inflow SDI and MFI of four CMs decreased to different degrees compared with test raw water,and overall trend was that the smaller the pore size of membrane,the lower the outflow SDI and MFI,the low trend meets the requirements of nanofiltration inflow SDI of less than 5 and MFI of less than 10.However,the removal of organic matter by the four CMs was less than 10% and the removal of inorganic salt ions was less than 2%.The smaller the membrane pore size,the more frequent the cleaning,which not only affects water treatment capacity and the stability of nanofiltration system,but also the higher operation and maintenance costs.Comprehensive comparison,0.5 μm CM has a relatively slow membrane flux rate drop and a lower cleaning frequency,which makes it more suitable as a nanofiltration pretreatment.