A biotechnological perspective on sand filtration for drinking water production

Gravity-driven sand filters are the dominant groundwater treatment technology for drinking water production. In the past, physicochemical reactions were often assumed to play the main role in the removal of contaminants, but recent breakthroughs showcase the vital role of microorganisms. In this Current Opinion , we thoroughly assess the current understanding of biology in sand filters and explore the potential benefits of shifting toward designs aimed at promoting biological reactions. We highlight the main bottlenecks and propose key areas to be explored toward the next generation of sustainable, resource-efficient groundwater biofilters. • Recent microbial insights shed light on groundwater filter black box . • Promoting biological iron oxidation significantly improves process performance. • Contribution of biological manganese and arsenic oxidation is most likely underestimated. • Nitrification problems often arise from (by)products of iron and manganese oxidation. • Biological processes are key towards resource-efficient groundwater treatment.