A study of a solar powered hypochlorite solution generator for drinking water disinfection in rural areas.

This dissertation reports on the use of solar energy in the electro generation of sodium hypochlorite solution for rural drinking water disinfection. A hypochlorite solution generator was designed, constructed and its applicability in water disinfectant production was studied. The study showed that the use of solar energy in electrogeneration of sodium hypochlorite and for charging a lead/acid battery was a useful technology for rural communities of developing countries. The generator was most effective in generating aqueous sodium hypochlorite solution when using a flow-through cell and raw brine flowing through at rates greater than 28 cm 3/min. Sodium hypochlorite solution with a concentration of 0.2% available chlorine was obtained in water cooled, once through, flow through cell system at a flow rate of 29 cm3/min. this system produced current efficiencies higher than 90 percent. The solar powered hypochlorite generator system was used to study disinfection of samples of several natural waters in Tanzania. The water samples used were chosen such that they represented surface water of international standards in their physical and chemical parameters but had high bacteria counts similar to those reported by other researchers. Results showed up to 100 percent of bacteria kill could be achieved in all the water samples. The effect of hypochlorite on corrosion of the local steel pipes ferrying disinfected water was also studied. A comparison of the change in weight of the pipes with hypochlorite has revealed that at higher sodium hypochlorite concentration and with pH controlled at around 4.0, large amounts of weight loss, by corrosion, occur in cast iron water pipe specimens. Those tested under alkaline conditions did not show this trend. The weight loss observed in this work were slightly lower when compared to corrosion due weight loss already reported in literature