CAWST

The village of Na Ngom Mai in Laos had 76 Biosand filters (BSF) installed in January 2008. Five months later, a household survey has found that more than 92% of end users are satisfied with the taste, smell and appearance of the water from the filter.

The evaluation was conducted by the senior staff of Laos Ministry of Health, the National Centre for Water Supply and Environment (Nam Saat), who were not directly involved in the project’s implementation. Using simple evaluation tools, the staff captured the current situation, users’ perceptions, water quality, effectiveness and acceptability of the filter.

CAWST hosted a ‘Project Implementation for the Biosand Filter’ to introduce the BSF technology in Lao in 2006 with the participation and support of local government and non-governmental agencies. Nam Saat decided to implement a filter pilot project in two villages, with the support of CAWST, UNICEF, and WSP-WRP (the World Bank).

To ensure quality control for the technical aspect of the project, CAWST worked with Nam Saat to facilitate an evaluation of the pilot project and also train the evaluation team members to ensure that they are able to carry out independent evaluations in the future.

According to Betman Bhandari, CAWST’s Education Program Developer, “Nam Saat has sufficient water quality testing kits and materials but their staff were not well trained on how to carry out a water quality survey. Therefore, CAWST spent a couple of days of training them on the equipment calibration and evaluation methods before carrying out a field survey. The field survey questionnaire was discussed within the evaluation team and modified according to the local context. Every step of water quality tests and the field survey were discussed the following evening which further enhanced the confidence of the team members.”

The survey found that the filter users were satisfied with the quantity of filtered water and that it was adequate for their drinking and cooking purposes. All villagers expressed that operating the filter was easy and most family members were using the filter properly.

The Na Ngom Mai Village Head, Mr. Vong, mentioned, “All villagers demanded for the filter and now most villagers have a BSF at their home. A few households still have not received a filter, but I plan to provide them one in the near future. In the past, we had to spend between 50,000-80,000 kips per month for drinking water which was about one third of our villager’s monthly income. Nowadays, this expenditure is not necessary for drinking water. Similarly we are expecting that cost of treatment and medicine will be reduced significantly. The filter water looks like a “tiger brand” bottle water and its taste is good. We all feel that it is easy for the everyday operation and maintenance of the filter. We recommended the BSF to our neighbour villages and relatives”.

In regards to the water quality, most chemical contaminants complied with the national drinking water standards. Results of water quality tests show that only 17% of source water is reasonable quality (<10 fecal CFU per 100mL) but after filtration, 71% of the filtered water is of good quality.

Focus Group discussions revealed that the Technical Committee members at Nam Saat have the confidence to replicate the project in other parts of the country. “I would like to thank Centre for Affordable Water and Sanitaton Technology (CAWST), Canada to support us to enhance our technical capacity to implement biosand filter projects in rural communities. Moreover, I would like to thank them for mentoring our staff to carry out the evaluation of biosand filter project including water quality testing in the effective and efficient way,” wrote Dr. Bouakeo Suvanthong, Chief of Environmental Health Division for National Centre for Environmental Health and Water Supply within the Lao PDR Ministry of Health.

In a literature review conducted by a team of researchers at University of North Carolina, Dr. Mark Sobsey, who led the study, affirms that ceramic and biosand filters have been shown to improve water quality and reduce diarrheal disease in epidemiological studies.

The team reviewed a variety of household water treatment technologies including chlorination with safe storage, combined coagulant-chlorine disinfection systems, solar disinfection (SODIS), ceramic filters, and the biosand filter. Ceramic and biosand filters were identified as the most effective with the greatest potential to become widely used and sustainable for improving household water quality to reduce waterborne disease and death.

The criteria used included: water quantity produced, application to a wide range of source water qualities, ease of use and time treating water, cost to treat, and supply chain requirements. Post-implementation use and sustainability evidence for each of the technologies were also summarized.

According to the study, both filters have been shown to improve water quality and reduce diarrheal disease in epidemiological studies, and follow-up studies document sustained, effective performance long after implementation, with filter usage rates remaining high post-implementation. Ceramic and biosand filters have also shown the potential for large scale adoption, as they are used by over 500,000 and 1.5 million people, respectively.

The study also noted that understanding the human behavioural factors that drive people to adopt and continue using technologies is crucial for widespread adoption and continued effective use.

The complete study can be purchased at http://pubs.acs.org/cgi-bin/abstract.cgi/esthag/2008/42/i12/abs/es702746n.html

Sobsey, M., Stauber, C., Casanova, L., Brown, J., and M. Elliott. Point of Use Household Drinking Water Filtration: A Practical, Effective Solution for Providing Sustained Access to Safe Drinking Water in the Developing World. Environmental Science & Technology, 42 (12), 4261–4267, 2008. 10.1021/es702746n. Web Release Date: May 13, 2008.