Study on Natural Organic Matter Removal and Trihalomethanes Control in Uganda's Water Treatment Plants
Research conducted at Kampala and Masaka water treatment plants in Uganda evaluated volcanic ash, pumice, and Moringa oleifera for natural organic matter (NOM) removal. Coagulation and filtration tests revealed challenges specific to each plant's raw water sources.
The Ggaba plant showed operational and design issues requiring modifications, while Masaka experienced a 4000% increase in total trihalomethanes due to pre-chlorination. Characterization of NOM indicated a hydrophilic nature without variation through treatment processes.
Pilot and laboratory tests demonstrated effective results, with a simple horizontal flow roughing filter at Masaka achieving 27% dissolved organic carbon (DOC) and 89% ferrous iron removal. Using pumice and hydrogen peroxide improved DOC removal to 68%.
A jar test indicated that alum combined with M. oleifera as a coagulant aid is effective for waters with high humic and iron content. The study confirmed that roughing filtration with hydrogen peroxide can replace pre-chlorination, and volcanic ash is a suitable filtration material, increasing filter run length by 2.5 times compared to mono medium columns.
