Investigating the efficiency of a Biosand filter :

Abstract

Over 1 billion people in the world lack access to safe water. Nearly all of these people live in developing countries, especially in rapidly expanding urban fringes, poor rural areas and indigenous communities which includes our very own Uganda, Municipal water treatment systems are frequently impractical and often un affordable in these settings. At the present time household water treatment systems provide the only reasonable alternative for many. Due to the increase in the number of deaths reported every year as a result of drinking contaminated water, Point of Use(POU)water treatment systems are encouraged in rural areas of developing Countries. One of the most promising is a Bios and filter. However, despite this successful implementation there has been almost no systematic process engineering research to substantiate the effectiveness of the BSF in its design and operation. This study is proposed for five mouths targeting, a population segment of Busia district, Busire village who depend on river Okame. The major objectives of this research were to (1) Investigate the rural raw water quality, parameters of river Okame (2). TO determine the effects of hydraulic retention time on removal of turbidity and microbiological contaminants and (3) determine the percentage removal of microbiological contaminants and turbidity using a Bios and filter Feed water was charged to the filter for 6 weeks. The performance of the filter in reducing microbial concentrations was highly dependent upon filter ripening over weeks of operation. Reductions of E. coli ranged from 96% to 99% with geometric mean reductions after at least 30 days of operation of 98.5% Turbidity reductions ranged from 179%to 85% Ecoli effluent data indicates that E.coli reduction by BSF may differ substantially depending upon the specific pathogens. It is recommended that this should, be looked into quantitatively. During the raining seasons, the raw water was highly turbid thus the author recommends sedimentation or design an extra feature in the unit that caters for turbidity.