School of Civil Engineering, Wuhan University, Wuhan, Hubei 430072, PR China; Engineering Research Center of Urban Disasters Prevention and Fire Rescue Technology of Hubei Province, Wuhan University, Wuhan, Hubei 430072, PR China.
College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
Sci Total Environ. 2018 Dec 10;644:306-314. doi: 10.1016/j.scitotenv.2018.06.220. Epub 2018 Jul 11.
We investigated biofouling in ultrafiltration (UF) for drinking water treatment and its control by backwashing with chlorinated-water or pure water. By using sodium azide to suppress biological growth, the relative contribution of biofouling to total fouling was estimated, and its value (5.3-56.0%) varied with the feed water, and increased with the increases of filtration time and membrane flux. The biofouling layer could partially remove biodegradable organic matter and ammonia (32.9-74.2%). Backwashing using chlorinated-water partly inactivated the microorganisms (23.8%) but increased the content of extracellular polymeric substances (7.7%) in the biofouling layer. In contrast, backwashing using pure water led to a looser and more porous fouling layer according to optical coherence tomography observation. Consequently, the latter was more effective in reducing fouling resistance (33.41% reduction) compared to backwashing by chlorinated-water (8.6%). These findings reveal the critical roles of biofouling in pollutants removal in addition to membrane permeability, which has important implications for addressing seasonal ammonia pollution.
我们研究了饮用水处理中超滤过程中的生物污染及其通过氯化水或纯水反冲洗的控制。通过使用叠氮化钠抑制生物生长，估计了生物污染对总污染的相对贡献，其值（5.3-56.0%）随原水而变化，并随着过滤时间和膜通量的增加而增加。生物污染层可以部分去除可生物降解的有机物和氨（32.9-74.2%）。使用氯化水进行反冲洗部分灭活了微生物（23.8%），但增加了生物污染层中胞外聚合物物质的含量（7.7%）。相比之下，根据光相干断层扫描观察，使用纯水进行反冲洗会导致污染层更加疏松和多孔。因此，与使用氯化水反冲洗相比（减少 8.6%），后者在降低污染阻力方面更有效（减少 33.41%）。这些发现揭示了生物污染除了对膜通透性外，在污染物去除方面的重要作用，这对于解决季节性氨污染具有重要意义。
