Sand filtration is frequently used in the treatment of groundwater to remove dissolved iron. Iron and manganese in the groundwater are oxidised by aeration and the flocs formed are subsequently trapped in the sand filter. After a certain period of time, the filter is saturated with particles and must be cleaned to prevent it from blocking up completely. The sand filters are cleaned by backwashing with air and/or water.
Sand filters can be a great pre filter for ultrafiltration modules and systems since it filtrates very accurate. An sand filter is not used to remove bacteria and virusses, therefore an ultrafilter should be installed downstream the sand filter.