Browsing by Author "Wali, Umaru G."

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    Characterization of wastewater from an Abattoir in Rwanda and the impact on downstream water quality
    (2010-01) Muhirwa, Déogratias; Nhapi, Innocent; Wali, Umaru G.; Banadda, Noble; Kashaigili, Japhet; Kimwaga, Richard
    This study analyzed processes and products at Nyabugogo Abattoir in Kigali, Rwanda, and investigated how they can be optimized for environmental safety. The average capacity of the abattoir is 566 cattle and 1,512 goats and sheep slaughtered per week. The study assessed the quantity and quality of different raw materials, by-products and wastewater streams and the potential impacts of applying cleaner production principles in abattoir processes. The samples were collected fortnightly, and analyzed using Standard Methods. The analysis emphasized on nutrients, biologically active constituents, and receiving water impacts. The data were processed for trends and variance using SPSS computer package. The wastewater parameters analyzed are temperature, salinity, conductivity, turbidity, dissolved oxygen pH, TSS, TDS, BOD5, COD, fat oils and grease, NO3-N, TKN, total phosphorus, chloride, calcium and total coliforms. The findings showed that the abattoir wastewater streams' total chemical oxygen demand (TCOD) ranged from (7,533±723) for evisceration to (23,778±1,673) mgl-1 from slaughtering step and the discharge into Mpazi River increased its TCOD from (213±29) to (852±94) mgl-1. The TSS varied between 2,452±51 from the slaughter process and 5,252±174 mgl-1 for the effluent from the goat and sheep slaughter section. Results from the bacteriological analysis showed that the average abattoir wastewater discharge count was (560±81)105 cfu/100ml of total coliforms which increased from (2.8±0.58)105 to (8.2±0.86)105 cfu/100 ml. It was concluded that the current effluent quality is not suitable for discharge into watercourses. It was recommended that further treatment of the effluent is required coupled with the application of cleaner production principles.
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    Heavy Metals Inflow into Lake Muhazi, Rwanda
    (2012-01) Nhapi, Innocent; Wali, Umaru G.; Usanzineza, Denise; Banadda, Noble; Kashaigili, Japhet; Kimwaga, Richard; Gumindoga, Webster; Sendagi, S.
    Most tropical African lakes are facing pollution problems due to the rapid population growth and industrializa-tion in their riparian communities. Lake Muhazi in Rwanda is one of such lakes which has experienced a dramatic decrease in fish production since the eighties, with also reports of low water transparencies and high turbidities. The lakeshores are now being developed for ecotourism and this requires sound environmental management to make the planned activities viable. The purpose of this study was to assess heavy metal pollution in the tributary rivers of Lake Muhazi. The concentration of heavy metals in major tributaries was monitored for the period July to October 2007. The parameters studied are cadmium, chromium, copper, iron, lead, manganese, zinc, pH and temperature. Fourteen sampling stations on the Inflow Rivers and the spillway were monitored fortnightly. The samples collected for heavy metal analysis were preserved and stored in cooler boxes and analyzed in the laboratory using Standard Methods. Temperature and pH were measured in the field using HACH field testing kits. The concentration (mean ± standard deviation) of Zn was found to be 0.040±0.103 mg/L, Cd 0.031±0.007 mg/L, Pb 0.487±0.452 mg/L, Fe 7.53±13.34 mg/L, Mn 1.01±1.31 mg/L, chromium 0 mg/L and copper 0 mg/L. The concentrations of measured parameters deviate much from the recommended ones thus posing serious problems to aquatic life. It has also been shown that the high metal concentration levels in Lake Muhazi are related to landuse activities in the catchment. It is thus recommended that farming practices and erosion be controlled in the catchment to contain pollutant discharges into the lake. Lead is the main anthropogenic pollutant which has been found in the watershed of Lake Muhazi.
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    Integrated Flood and Drought Management for Sustainable Development in the Kagera River Basin
    (2011) Munyaneza, Omar; Ndayisaba, C.; Wali, Umaru G.; Mulungu, Deogratias M. M.; Dulo, Simeon O.
    Integrate Flood Management (IFM) integrates land and water resources development in a river basin, within the context of Integrated Water Resources Management (IWRM), with a view to maximizing the efficient use of flood plains and minimizing loss to life. For flood management to be carried out within the context of IWRM, Nile river basins should be considered as integrated systems. Socio-economic activities, land-use patterns, hydro-morphological processes, etc., need to be recognized as constituent parts of these systems. The aim of this paper is to identify the flood and drought periods in the river basin for future agricultural development and establish functioning integrated measures for flood and drought management in the Kagera Basin, which is one of sub-basin of Nile basin. Digital Elevation Model (DEM) map was used for Kagera river basin delimitation and its patterns (topography, land use and land cover). Impacts of floods and drought on livelihoods of residents were outlined. Survey methods were also used to derive a risk assessment methodology and management plans for hazard prone communities. The flood disaster management strategic plan in the Kagera Basin contains three phases such as prevention and mitigation before the occurrence, response in case of disaster, and rehabilitation after the occurrence. Thus, the most important key strategy is the cooperation and co-ordination across institutional boundaries, noting that the mandates of many institutions will either cover only part of the river basin or extend well beyond the basin boundary. At the core of integration is effective communication across institutional and disciplinary boundaries, which can take place only if there is a perception of common interest. Emphasis was on the adoption of flexible strategies tailored to each flood-prone region (characterized by their various physical, social, cultural and economic aspects) – recognizing the importance of evaluating different options and their relative advantages and disadvantages.