A review with 77 refs. covering coagulation and microfiltration, softening of water, removal of iron and manganese, adsorption on alumina, iron oxide- or MnO(2)-coated sand, granulated ferric hydroxide, zero-valent iron, hybride and other ion exchangers, activated carbon, and membrane processes. WHO (1993) recommends 10 mu g As/l. as the max. contaminant level in drinking water.