Harnessing biodegradation potential of rapid sand filtration for organic micropollutant removal from drinking water: A review

A cost-effective approach for efficient organic micropollutants (OMPs) removal is to optimize existing infrastructure at drinking water treatment plants. A promising option is rapid sand filtration (RSF), as OMPs removal has been observed in this treatment technology. However, the mechanisms and pathways involved are not fully understood and strategies to optimize removal have yet to be thoroughly explored. Therefore, this article firstly described basic RSF functions that can support OMPs removal. OMPs can be removed by chemical and biological Mn/Fe oxides or degraded co-metabolically by ammonia oxidizing bacteria and methane oxidizing bacteria. In addition, heterotrophic bacteria can metabolically transform OMPs and their transformation products. Then, we reviewed current literatures described OMPs removal in RSF, showing biodegradation can contribute significantly to OMPs removal. Thereafter, we presented strategies to improve OMPs biodegradation, including bioaugmentation, optimizing hydraulic conditions by adjusting contact time and backwashing intensity, and adding biocarriers to retain biomass during rapid flow rates. Finally, we provided recommendations for further research towards optimizing and maintaining OMPs removal in RSF for safe drinking water production. This review therefore gives a critical evaluation of RSF-based technologies for OMPs removal from drinking water and provides recommendations for further improving OMPs removal in RSF.