Household sand filters for arsenic removal : an option to mitigate arsenic from iron-rich groundwater

This report describes the investigation of the arsenic removal efficiency from groundwater by household sand filters in 43 households in rural areas of the Red River Delta in Viet Nam. A mean arsenic removal efficiency of 80% was achieved in groundwaters containing 10-420 ug/L arsenic, 0-47 mg/L iron and 0-3.7 mg/L phosphorus. High iron concentrations clearly enhance arsenic removal, whereas increased phosphate levels (>2 mg P/L) partly lower the removal efficiency. Sand filters use locally available materials, are operated without chemicals, can treat a reasonable amount of groundwater within a short time, and can be easily replicated by the affected communities. The observable removal of iron from the pumped water immediately makes the use of a sand filter intelligible even to people who have never heard of the arsenic problem. Thus, household sand filters are a viable option for arsenic mitigation of iron-containing groundwater in Viet Nam and other arsenic affected regions. The report includes leaflets for widespread information on construction, use and maintenance of household sand filters.