Rural Water Disinfection In The Developing World: Designing A General Chemistry Lab Experience

Abstract

A simple electrolysis apparatus was set up with a 10 wt% NaCl solution using a stainless steel cathode and a graphite anode to produce a hypochlorite ion solution. The hypochlorite ion solution was quantified to around 600 ppm by spectrophotometry analysis at 515 nm using N,N-diethyl-p-phenylenediamine (DPD). The efficacy of the hypochlorite solution was determined by contaminating a 1 ppm solution of the hypochlorite solution with the sulfide-producing bacterium, Salmonella typhimurium. At this level, the bacteria were not viable. The procedure used to generate the hypochlorite solution and determine its disinfection effectiveness was adapted to a lab experience for first-year chemistry students.