Increase access to clean water in households and schools

Lack of access to water supply and sanitation has significant health impacts, According to WaterAid, more than 3 million people in Rwanda don’t have access to clean water, 4.5 million don’t have access to adequate sanitation in Rwanda and 600 children under five die every year from diarrhea caused by unsafe water and poor sanitation in Rwanda.

What we contribute to address this issue?

To contribute to reduction of the huge number with no access to clean water and unsafe water related consequences, Hand In Hand for Development in collaboration trains communities on entrepreneurship and bio sand water filter construction; thereafter the trained groups spread bio sand water filters in their communities as tool to access clean water. HIHD provides also bio sand water filters to families of women and children living with HIV/AIDS and other vulnerable families.

What we expect from our contribution

⦁ Access to clean water in communities
⦁ Improved living conditions in communities.
⦁ Improved health conditions
⦁ Access to clean water at a low cost in communities

What is a bio sand water filter (BSF)?

A biosand filter (BSF) is a point-of-use water treatment system adapted from traditional slow sand filter. Biosand filters remove pathogens and suspended solids from water using biological and physical processes that take place in a sand column covered with a biofilm. BSFs have been shown to remove heavy metals, turbidity, bacteria, viruses and protozoa. BSFs also reduce discoloration, odor and unpleasant taste. Studies have shown a correlation between use of BSFs and a decrease in occurrence of diarrhea. Because of their effectiveness, ease of use, and lack of recurring costs, bio sand filters are often considered appropriate technology in developing countries.

The bio sand Filter is a proven technology, which removes pathogens such as bacteria, protozoa and helminth. BSFs are also somewhat effective for the removal of virus (CAWST 2009). Physical parameters such as turbidity and iron are also eliminated from drinking water. However, dissolved chemicals (such as organic pesticides or arsenic) are not removed. The treated water generally has an agreeable color, taste and odor. The table below shows the bio sand filter treatment efficiency in removing pathogens, turbidity and iron (adapted from CAWST 2009).

Health impact studies estimate a 30 to 47% reduction in diarrhea among all age groups, including children under the age of five, an especially vulnerable population group.

Effectiveness of bio sand water filter

Applicability

Bio sand water filters are suitable for the treatment of water at household-, school- or community-level. BSF can efficiently and directly treat contaminated surface or ground water since it also removes turbidity and iron. However, it is recommended not to use water with turbidity more than 50 NTU. Further, dissolved chemicals (e.g. organic pesticides or arsenic) are not removed. Chlorinated water should not be poured into this filter as chlorine kills microorganisms presented in biofilm resulting in low pathogen removal performance. Nevertheless, the water can be chlorinated after filtration in order to improve the security for elderly or infant members of the household/community. A BSF should be constructed only by trained technicians. Though the construction and installation look very simple, incorrect filter design and installation can lead to poor filter performance. However, materials are generally locally available and the construction by trained local staff may create opportunities for local business.

Advantages

⦁ High removal of pathogens
⦁ Removal of turbidity, color, odor and iron (water tastes and looks good)
⦁ Relatively high flow-rates can be achieved (over 30 L per hour)
⦁ One-time installation with few maintenance requirements and negligible operation costs
⦁ Long life
⦁ Can be fabricated from locally available materials generating an opportunity for local businesses
⦁ Easy to operate and maintain

Disadvantages

⦁ Biological layer takes 20 to 30 days to develop to maturity
⦁ Low rate of virus inactivation
⦁ High turbidity (> 50 NTU) will cause filter to clog and requires more maintenance
⦁ Requires that the filter be used on a regular basis
⦁ Cannot remove dissolved compounds
⦁ Can be difficult to move or transport (due to weight)
⦁ Lack of residual protection (risk of re-contamination)