Reduction of microbial contamination using household techniques in rural area of India

Abstract

Groundwater is the major source of domestic water for people residing in Amingaon – a rural area in North Guwahati, Assam, India. However, it contains an excessive amount of dissolved iron (Fe) (11.3 mg/l); hence, the people resort to the use of indigenous household groundwater filter (IHGF) units. A survey of different variants of IHGF units within a radius of 5–6 km from the campus of Indian Institute of Technology Guwahati reveals that the filter medium – that is, river sand, gravel, wooden charcoal and mesh – are arranged in different combinations layerwise and bounded in plastic buckets, reinforced cement concrete rings and tin (Sn) containers. An IHGF unit is selected for performance monitoring. The iron concentration in the filtered water is within the permissible limits (0.3 mg/l), but when the water is assessed for pathogenic contamination using the hydrogen sulfide (H2S) strip test, it is found to be contaminated with pathogens, making it unfit for drinking. Efforts have been made to reduce the faecal microbial contamination present in the filtered groundwater using household treatment options such as additional filtration using folded cloth, use of Ocimum tenuiflorum (tulsi) and copper (Cu) utensils and solar disinfection (Sodis). Sodis is found to be the most effective in reduction of faecal microbial contamination present in the filtered water.