The Viability of Biosand Filters to Recycle Water in a School Environment

Krishi D. Mavani, Raju Baloliya

Abstract: The biosand filter is a slow sand water filtration system that is widely used in developing countries. The filter works through the use of a biological layer to kill pathogens in the water. The focus of this research was to determine the effectiveness of a biosand filter in relation to its ability to filter greywater- contaminated water from sinks, showers, and dishwashers- from handwashing and create recycled water in a school. River water was put through the filter daily to build the biological layer, a layer of the filter with live bacteria. Bacterial samples concluded the biological layer took six weeks to grow resulting in filtered river water having the same number of small bacterial colonies as school water. The newly filtered water was placed into a female?s bathroom and used as hand washing water. Hand washing greywater was collected from the bathroom to be recycled but, it contained a high concentration of all-natural soap which the biological layer was unable to process. To determine the number of female students who used the bathroom, data was collected on bathroom water usage over a 2-month period. Data on female bathroom usage showed that the females? bathroom sinks used 0.67% of the school water, resulting in an average of Rs.650 (INR) water cost and a Rs. 780 (INR) sewer charge over a 2-month period. Ultimately, it was found that implementing biosand filters in a female bathroom is beneficial. However, it would not be feasible to recycle greywater due to the soap harming the biological layer composed of pathogen killing bacteria. The inability of the filter to recycle greywater results in a sewer cost greater than the cost of the water itself, making the bio sand filter financially impractical.

Keywords: Biosand Filter, Recycle Water, pathogenes