Designing Iron‐Amended Biosand Filters for Decentralized Safe Drinking Water Provision

There are ongoing efforts to render conventional biosand filters (BSF) more efficient for safe drinking water provision. One promising option is to amend BSF with a reactive layer containing metallic iron (Fe 0 ). The present communication presents some conceptual options for efficient Fe 0 ‐amended BSF in its fourth generation. It is shown that a second fine‐sand layer should be placed downwards from the Fe 0 ‐reactive layer to capture dissolved iron. This second fine‐sand layer could advantageously contain adsorbing materials (e.g. activated carbons, wooden charcoals). An approach for sizing the Fe 0 ‐reactive layer is suggested based on 3 kg Fe 0 per filter. Working with the same Fe 0 load will ease comparison of results with different materials and the scaling up of household BSF to large scale community slow sand filters (SSF).