Access to clean, safe water is spreading to Cambodia's rural areas thanks to the installation of arsenic mitigation technology.

Arsenic contamination of groundwater resources has become a significant health threat in rural Cambodia where people rely on groundwater for drinking, washing, and much of their daily domestic needs. Several cases of skin disease and cancer due to arsenic poisoning (arsenicosis) have been confirmed by Cambodia's Ministry of Rural Development (MRD) and Ministry of Health (MoH) over the years. A UNICEF study, commissioned by MRD, estimates that over 320,000 people in 1,600 villages are at risk.

But arsenic contamination is not new; it has been known in Bangladesh, India, Nepal, and Vietnam since the 1990s and effective mitigation options are available. It is crucial, however, to identify which technology can best be adapted to the local context.

Thanks to an ADB Water Pilot and Demonstration project in rural Cambodia, the Kanchan Arsenic Filter (KAF) was identified as a suitable and affordable arsenic mitigation technology for the Asian country.

Testing the water

The grant for the pilot project, approximately $50,000, allowed the installation of a total of 30 KAF units in 30 households and benefitting about 200 people in Cambodia's Kiensvay and Prey Veng provinces. Water in the selected households represented various water chemistry conditions, covering the high to low range of the quality parameters believed to affect KAF's performance, namely arsenic, iron, phosphate, and pH-level.

The test involved pouring 20 liters of tube well water into each filter twice a day. The filtered water would be used only for washing and cleaning, not drinking. Staff from the Institute of Technology of Cambodia (ITC) and the MRD in-charge of the project made scheduled visits to test the water after filtration.

Water from each filter was tested 1 week, 6 weeks, and 10 weeks after installation to measure the 6 priority parameters according to Cambodian water safety standards, which include arsenic content, iron content, turbidity, pH-level, amount of total dissolved solids, and presence of E. coli. The result: 99% of all filtered water samples satisfied these water safety parameters.

KAF technology

The KAF technology was developed by the Massachusetts Institute of Technology (MIT), together with Canada-based Centre for Affordable Water and Sanitation Technology (CAWST). The principle behind KAF technology is simple, similar to many biosand water filters already in use in rural households, with many layers of gravel, stone, and sands. What makes it different is the layer of rusting iron nails that absorbs the arsenic.

In 2006, the KAF was singled out and proposed to be tested in Cambodia. The technology has been successfully implemented in Nepal and was specifically designed for arsenic contaminated tube wells in rural Asia. At present, each KAF unit costs $62 to produce, though it is estimated that mass production can bring down the cost to about $30. The KAF can filter at least 40 liters of water daily, more than enough for a typical rural household.

Looking forward

The pilot project, completed in January 2009, strengthened the knowledge and capacity building of ITC on water treatment and field research, especially in quality assurance and control. It also helped MRD increase its knowledge and capacity in household water treatment technologies, verification process, field work, and project management.

One lesson from the pilot project is that water technology verification is more than just water quality testing; it also involves setting policies on which the water testing results will be measured against. Official guidelines that define safe drinking water quality should be put in place. The pilot project provided a needed first step for policy-makers to establish such a guideline.

About 15,000 households are now using KAF technology which is being promoted by the government, UNICEF, UN-Habitat, Red Cross, Finnida, a number of local NGOs, and a few private businesses. In the meantime, some 27,000 rural households in the country are still affected by arsenic contamination and are clamoring for the KAF.

The Country Water Action series was developed to showcase reforms and good practices in the water sector undertaken by ADB's member countries. It offers a mix of experience and insights from projects funded by ADB and those undertaken directly by civil society, local governments, the private sector, media, and the academe. The Country Water Actions are regularly featured in ADB's Water for All News, which covers water sector developments in the Asia and Pacific region.