These adsorption filters feature low-cost and low-maintenance solutions for the removal of arsenic from groundwater sources. Arsenic is immobilized by activated alumina, activated carbon or iron/manganese-oxide coated medium (often sand or similar). The filter yield is limited: storage facilities are advised for continuous water availability.
Cheap removal method, depending on filter size. Small (in-door) containers USD12-30 (Kanchan filter). O&M is inexpensive and comprises the replacement of the sand medium (at bigger filter) or the corroded iron medium.
Serious awareness-raising on arsenic threat needs to be complemented by trainings on filter building. Larger concrete or brick containers require mason training. Once the need of arsenic removal is understood by the users, monitoring of removal quality is required centrally.
Arsenic contamination most relevant for South-East Asia (from East-India to Vietnam), but also in other regions. Treatment efficiency depends strongly on presence of other contaminants: iron ions improve, phosphate reduces removal efficiency. Safe disposal of spent filter media is advisable.
Larger tanks are often constructed with water storage tank to allow filter drying. Drying filter between filtering periods is crucial to keep removal efficiency high. Wet filters encourage bacterial growth which quickly reduces treatment efficiency by turning filter anaerobic.
Successfully disseminated solutions include Kanchan filter, Shapla filter, Sono filter and sand filters. Larger units may apply for shared household use. Comfort of use is slightly reduced by frequent replacement of sand filter. Limited operational activities when compared to precipitative arsenic removal methods.
No relevant remarks for Adsorptive arsenic removal.