10. Case studies

The TOP contains two promising case studies, both making use of iron oxide coated sand (IOCS), a by-product from groundwater treatment plants in the Netherlands and other countries, which makes an effective filter for arsenic.

Point- of-use filter – Bangladesh

UNESCO-IHE in close cooperation with Dutch water supply company VITENS have developed a family filter to remove arsenic at household level. Following trials, the design was twice improved. In later trials, supported by a local NGO, 12 family filters consistently removed arsenic to a level below the Bangladesh standard of 50 µg/L for a testing period in excess of 450 days, and ten out of 12 filters removed arsenic to well below the 10 µg/L WHO standard. The capacity of the filter is approximately 100 litres a day, sufficient for drinking and cooking for a typical family. Operation is simple and easy and the prototypes were well accepted.

Centralised removal system – Hungary

Within the European Union, Hungary is most seriously affected with arsenic in groundwater exceeding the EU norm in 400 towns and villages. UNESCO-IHE and partners have been testing demonstration scale pilot plants for arsenic removal in the Makó region. Extensive water quality analysis during several months of continuous operation confirmed the ability of this treatment technology to produce arsenic-free water and to remove methane, ammonia, iron and manganese. This technology has now been licensed for use in Hungary.

Further information

The TOP contains a full list of references and a wealth of information for further reading, listing books, articles and papers and helpful websites.