用于改进水质的生物膜技术

由于传统的和新兴的水处理技术可选择的范围很广，生物膜技术亦被广泛地用于水质的改进，并且它的应用范围正在不断增加．对于一个好的生物膜技术，其关键就是有一个适当高的比表面积．大比表面积可减少系统的体积，占地面积和造价．而另一方面，若比表面积太大，有可能引起氧传递和堵塞问题．对生物膜技术最好的选择取决于它具有什么用途．如果以体积小为主要目的，流化床生物膜反应器具有最高的比表面积．但是循环床生物膜反应器、生物曝气滤池和气升式内循环反应器比传统的滴滤床和生物塔的比表面积要高．生成甲烷的生物膜法具有最高体积负荷，因为在这一过程中，氧的传递不是限制因素．如果以出水质量为主要目的，曝气生物滤池具有较好的应用前景，因为它们也是以颗粒滤池形式操作．最后，当目的是还原氧化性的污染物，而不是去除BOD时，氢气渗透滤膜表面上附着生物膜的反应器已引起人们的注意．

Biofilm technology used to improve water quality

Biofilm technologies are widely used to improve water quality, and the applications are increasing due to the wide range of traditional and emerging options. One key to a good biofilm technology is having an appropriately high specific surface area. A large specific surface area decreased the systems volume, footprint, and capital costs. On the other hand, the specific surface area can be too large, and this can cause problems of in oxygen transfer and clogging. The best choice for a biofilm technology depends on what benefit is most valuable. If a small volume is of prime importance, fluidized - bed biofilm reactors have the highest specific surface area, but circulating - bed biofilm reactors, biological aerated filters, and the internal airlift reactor have significantly higher specific surfaces areas than do traditional trickling filters and biological towers. The highest volumetric loadings can be attained with methanogenic biofilm processes, for which oxygen transfer is not a limiting factor. If excellent effluent quality is a primary goal, biological aerated filters offer good potential, since they also operate as particle filters. Finally, when the goal is to reduce oxidized contaminants, instead of removing BOD, the H2 - based the membrane biofilm reactor gains a pre -eminent position.