Groundwater Purification Using Bio-Sand Filter Modified with Iron Oxide-Coated Sand and Activated Carbon

Abstract

Groundwater is the most used natural resource which serves different diverse purposes and alternative water supply for households mainly in rural areas. However, it is polluted by contaminants such as heavy metals, total hardness and coliform bacteria. One such promising water treatment technology for households in rural areas is the Bio-sand Filter (BSF) because of its low cost and efficient removal of contaminants. Although BSF is efficient to remove contaminants, there is still needed to improve the flow rate and the performance of removing pollutants from groundwater. Therefore, this study focused on the development of a laboratory-scale Modified Bio-sand Filter (MBSF) that was combined with Iron-oxide Coated Sand (IOCS) with Granular Activated Carbon (GAC) made from coconut shells to purify groundwater. Laboratory scale of filters were performed in this study. Groundwater was collected from household’s well water in Kean Svay district, Kandal province. The filters were operated by filling the water source with 10 liters per day and operated for 20 days. Heavy metals were measured by Atomic Absorption Spectroscopy (AAS) and Arsenator. Total hardness was analyzed by Ion Chromatography (IC). Target coliform bacteria such as E. coli and total coliform were cultured by spread plate method. Flow rate was observed by setting time for 1 minute and measure the volume of effluent water. By the results, all physicochemical parameters of MBSF were within the standard limit of drinking water. MBSF showed significantly better removal efficiency for arsenic with 100% than BSF while MBSF can also remove Mn and Fe which was under the drinking water standard of WHO and MIME. Total hardness was achieved more than 80% in MBSF, while BSF with only 40%. MBSF also performed slightly better than BSF as well in removing both E. coli and total coliform with more than 90% reduction. The flow rate of the MBSF was faster about two and a half times than the flow rate of BSF with the average of 0.15 L/min for MBFS and 0.06 L/min for BSF. The results from this study contributed to the improvement of household water treatment method for purifying groundwater efficiently in rural areas.