ABSTRACT
A In order to reduce arsenic concentrations in drinking water to very low levels (below <µg1/L), we investigated the effect of coagulation with iron(III) prior to ultrafiltration on arsenic removal. It was found that arsenic could be removed to below 1 µg/L, as long as only infiltrated dune water is used as a source. When natural groundwater is also abstracted, removal of arsenic by coagulation – ultrafiltration is not sufficient due to resulting higher concentrations of arsenic and various anions in the feed water. At a dose of 0.4 mg Fe/L and a flux of 55 L m-2 h-1, membrane fouling could be controlled by chemically enhanced backwashing with citric acid and sodium hypochlorite.
