Household water purification system comprising cartridge filtration, UVC disinfection and chlorination to treat turbid raw water

Abstract

A system composed of cartridge membrane filters (25 μm, 10 μm and 1 μm opening size), UVC-lamp and chlorinator was constructed and tested with high turbidity water (up to 236 NTU). The proposed system treated around 180 L day−1 of river water and the following parameters were analysed: pressure drop in filters, turbidity, apparent colour, true colour, Escherichia coli, total coliforms (TC), UV 254nm transmittance, UV 254nm absorbance and total organic carbon in both raw and treated water. The study was conducted in three phases. In Phase 1, the raw water was rested for 24 h in a settling tank before filtration in a 10 μm cartridge filter followed by one cartridge of 1 μm, a UVC-lamp (17 W) and manual chlorination. In Phase 2, a 25 μm filter was added before the 10 μm filter. In Phase 3, a blanket filtration step was added before the raw water entered the rest tank. The filtration trials lasted 7, 21 and 69 days in Phases 1, 2 and 3, respectively. The turbidity reduction of the system ranged from 30% to 93%. Disinfection by UVC-lamp was able to inactivate E. coli up to 5.00log, however the TC reduction was lower (up to 4.24log). The final manual chlorination with a dose of 3 mg L−1 of sodium hypochlorite increased the reduction of TC (up to 5.94log), regardless of water turbidity. The system was effective in improving water quality aimed at implantation in rural communities for domestic use at household level.