Fabrication of rapid sand filter for water treatment using sand and activated carbon

Abstract

It is pertinent to provide safe drinking water to the people as quality of water keeps deteriorating. According to World Health Organization (WHO), water and hygiene are the primary drivers of public health. Filtration is a water treatment process used for removal of microorganisms and colloidal matters from raw water, therefore this study aims at comparing the effects of sand and activated carbon when used separately in rapid sand filters for water treatment. Fabrication of two models of the rapid sand filters were carried out with 1.2mm stainless steel plates. One of the filters was loaded with gravel (grain size 5mm) at the bottom and this was followed by coarse sand (grain size 3mm) and fine sand (grain size 1mm) at the top. The second filter was loaded with gravel at the bottom and this was followed by coarse sand, fine sand and capped with activated carbon. Raw water, obtained from borehole was stored in a tank and made to pass through each of these filters independently. Sample of the raw water was collected for laboratory analysis in addition to samples of the treated water from each of the two rapid sand filters. The outcomes of the tests reveal that the filtration processes had positive impact on the raw water but the filter capped with activated carbon produced better quality water. The use of activated carbon as the topmost material in a rapid sand filter is recommended as it enhances the quality of treated water in parameters such as colour, conductivity, chloride, hardness, sulphate, total dissolved solids, sodium, magnesium, iron and total plate count. The rapid sand filters would afterwards be used for students’ practical to explain filtration as a water treatment process.