Improving Quality of Water from Murchison Bay using Clay from Chelel, Kapchorwa District, Ugandao

Pollution resulting from increased human activities is threatening Lake Victoria, its effects are characterized by eutrophication, high turbidity, pH, iron(II) concentration and chemical oxygen demand (COD). In this study we have investigated the effect of Fe-montmorillonite clay from Chelel on turbidity, pH, concentration of iron, total suspended soils, total nutrients and COD of water sampled from Murchison bay watershed of Nakivubo channel south of Kampala. Varying amounts of clay powder was vigorously stirred with water samples for 5 minutes, filtered using Whitman paper at ambient temperatures. The optimum concentration of clay of 0.4gl-1 was found to produce 73.5+ 2% fall in COD indicating elimination of microbes and organic waste. The pH of water became 6.3+ 0.2 showing that impurities had been bound to clay. The turbidity of filtrate dropped to 15.7+ 0.3NTUshowing that clarity of water was improved by adsorption of suspended solids to clay minerals. The concentration of iron(II) fell from 3.7 + 0.3 to 2.5+ 0.2mgl-1 indicating fairly high extent of heavy metal removal from Murchison bay (MB) waters. The TSS and nutrients in MB water   also decreased greatly when clay was stirred with water at ambient temperatures. The available data can be relied on to recommend use of this clay in treatment of waste water and/or sewage from Kampala. Further studies on combined use of clays with alums, zeolites and/or lime need to be carried out.&nbsp

How variations in concentrations of metal ions and suspended solids downstream river Rwabakazi in Uganda can be used to study pollution

Pollution is affecting river Rwabakazi in the Nile basin. Its effects are reflected by high turbidity, pH, total suspended solids, (T.S.S.), electrical conductivity, metal ions concentrations, and low concentration of dissolved oxygen (DO5). In this study, we report the variations in selected physicochemical parameters of waters of the Rwabakazi river.  Turbidity, pH, concentrations of selected metal ions, T.S.S., and DO5 of water sampled from three selected sites on the river in Kabale were very high. Mean DO5 fell from 96 ± 2 mg/L to 86± 1.5 mg/L downstream. The mean pH fell from 7.8 ± 0.03 to 7.6 ± 0.04, showing the removal of basic components. The turbidity dropped from370 ± 3 NTU to 305 ± 2 NTU, showing that the haziness of water decreased. The concentration of iron(II) fell from 320 ± 0.3 mg/L to 291 ± 0.2 mgL-1 indicating the fair extent of heavy metal ions downstream. The T.S.S. decreased from 330 ± 5 mg/L to 300± 5 mg/L, and concentrations of calcium and magnesium ions also decreased, providing evidence for self-purification. The available data suggests that river Rwabakazi is polluted as a result of poor agricultural practices, erosion, and flash flooding.  Further studies on nutrient and pesticide pollution of this river need to be carried out, and trees should be planted on steep open surfaces to minimize erosion.