Review of biologically active filters in drinking water applications

Biological water treatment processes are based on the growth of microbial communities capable of metabolizing contaminants through mediating oxidation–reduction reactions. Biologically active filters (BAFs) are applied in drinking water treatment for the removal of contaminants including natural organic matter, nitrate, trace organic compounds, perchlorate, sulfate, iron, and manganese. BAFs make use of a fixed film that develops on media such as sand, anthracite, granular activated carbon, or membranes. This biofilm is a diverse community, but the conventional biological treatment process basically takes a “black box” approach with respect to microbial community development. Controlling biofilm thickness and producing microbial communities fully adapted to target contaminants represent significant engineering challenges. This article discusses the advantages and applications of BAFs to remove contaminants in drinking water sources, reviews microbial communities in bulk water and biofilms, and summarizes the current fundamental knowledge about biofilm adhesion and control.