Removal of Physicochemical and Microbial Impurities of Water Using Modified Homemade Filter

摘要

Background: There are many different methods, which are used to purify water. Some are conventional and expensive, while others are traditional and small scale, still having interesting results in killing pathogenic organisms and reducing the concentration of some chemicals and other impurities, especially for rural communities of developing countries who are suffering from water borne diseases. But because conventional water treatment methods are not affordable in rural communities of developing countries, other small-scale methods are needed. An experimental study was conducted to test the effect of modified homemade filter in reduction of turbidity, fecal coliform, fluoride and its effect on pH and temperature. Method And Materials: Representative water samples were taken from’ kochi’ stream and laboratory analysis was done both for the raw water samples and the filtrates in school of environmental health laboratory, Jimma University. Filter tanks fitted with half-inch pipe were constructed and filled with stone (10 cm), gravel (9 cm), sand (40 cm) and crushed brick (10 cm) for fluoride test and local charcoal (10 cm), instead of the crushed brick for physical and biological test. Filter tanks without crushed brick, and without local charcoal were used as control. For the determination of fecal coliform, pH and temperature, turbidity and fluoride, MPN technique, pH meter, turbidimeter and Alizarin spectrophotometry method were used, respectively. Results: With a flow rate adjusted initially to 0.35 L/min the test resulted an average concentration of fluoride 1.42 mg/l (71.6%) from 5mg/l after filtered in a Modified Homemade Filter (MHMF1) with crushed brick. After a month operation the MHMF2 (with local charcoal) reduced the faecal coliform to 1 /100ml (99.95%) and turbidity to 0.13 FTU (99.83%), which was improved as the time of filter run increased and the flow rate decreased. CONCLUSION: The study showed that filtration of raw, fluoridated water with the study media could remove physical, chemical and biological impurities up to significant values for developing countries. The filter unit is very light in weight for easy transportation and costs 210 Ethiopian Birras of March 2004. Communities who have no access for treated water supplies can have this method as alternative, appropriate and cost effective technology with careful handling and timely cleaning. Ethiop J Helath Sci . Vol. 16, No.2 July 2006