23May2014

BIO SAND FILTER: Worth the Wait

Sonal Birla

According to the United Nations, 18 percent of world’s population lack access to safe drinking water. Even if the UN Millennium Development Goal to halve the population without drinking water by 2015 is achieved, 29% of the rural population, or 244 million people in India would still lack access to adequate safe, sustainable water. Access of households to safe drinking water is dependent on both water availability and quality. The poor quality of available drinking water has enormous implications on health.

While households in urban areas can afford water purifiers, rural communities still struggle with unavailability of clean drinking water in proximity to their households. Many women walk miles every day to fetch water. A direct outcome of this is that girls drop out from school to collect water along with their mothers or look after younger siblings when the mother is away. According to a UN water report, 2013, on an average, women and girls spend 6 hours in a day to fetch water. What a loss of productive time!

Most parts of the Mewat district of Haryana, predominantly an agrarian economy inhabited by a unique ethnic group named ‘Meo Muslims’, lack access to safe drinking water. Almost 55% of the geographical expanse of the district does not have fresh groundwater. Majority of the area in Nuh, Nagina, Punhana and Firozpur Jhirka blocks is characterised by brackish to saline ground water.

Piped water, hand pumps, wells (open wells and tube wells), submersible pumps and rain water are vital sources available for inhabitants to fend for their water needs. However, in absence of public wells in some villages, very few households who can afford to pay either purchase water or get their personal tube well/submersible pump installed. Rural households largely rely on public unprotected wells for procuring water for drinking. As a result, the inhabitants face a tradeoff between the availability and quality of drinking water.

Just having access to water is not enough; for drinking, quality is essential. Filtering water to ensure quality is not a common practice in the region. Those who filter water majorly use cloth. Other common practice such as boiling water is used only on doctor’s advice when somebody falls ill in the family.

In the absence of clean drinking water and with limited financial resources, bio sand filters (BSF) offer a low cost solution of providing clean drinking water to rural communities. A BSF is a simple container in which there are layers of sand and gravel that remove dirt, bacteria, viruses, and other physical and biological impurities from the water. The water poured at the top of the filter passes slowly through the several layers, and then travels up through piping encased in the concrete and out of the container for the user to collect.

BSF benefits all those rural households who fetch water directly from unprotected water resources. The benefits of BSF are acknowledged worldwide in terms of reduced disease incidence. BSF users in the villages of Mewat have shared similar experiences of decreased incidence of water borne diseases. “The frequency of number of people falling ill in my family has reduced by 70 percent’’, says Ismail of Khanpur village, Nagina block. Households using the BSF note that it requires no electricity or chemicals and can filter 0.6 litres of water per minute.

Despite the benefits, the adoption rate of BSF in rural households has been slow. The users comment that it is difficult to control the flow of water from the outlet in the filter in the absence of a tap. The households perceive the filter as an added responsibility to their daily household chores given the upkeep needed for the filter and the slow filtration process. Few other households also report a bad smell from the filter’s gravel content over time, as a result of which the filtration rate reduces.

A study conducted to find out the reasons behind the slow adoption rate revealed that the households are unaware of the design of BSF and the biological process of sand filtration that makes for the slow rate of filtration. In order to fill the gap, awareness on the working of BSF should be imparted to the households to make them understand the reasons for the slow filtration process, the absence of a tap in the filter and the importance of maintenance of gravel content to avoid bad smell. Once these corrective steps are taken, the BSF is surely an alternative ‘worth the wait’ in communities that do not have access to safe drinking water.