Biosand Filtration.
https://www.emergency-wash.org/water/en/technologies/technology/biosand-filtration
👉🏼 PDF: https://app.box.com/s/5bl7ifdr2n4zjerkaxo2drkqb7oqmn2k ____ Biosand Filters (BSF) remove suspended solids and microbial contaminants from water with varying levels of turbidity through a combination of physical and biological processes. They are an adaptation of the continuousflow traditional Slow Sand Filter T.9 and can be used intermittently, making them suitable for household use.