Daystar University Publications

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Browsing Daystar University Publications by Author "Achoka, J. D."

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    A Comparison of Transmittance of the Wastewater from Pan African Paper Mills (EA) Limited and River Nzoia Water in Kenya
    (Discovery and Innovation, 2001) Achoka, J. D.
    Colour (nuisance) chromophoric materials cause visible and negative impacts on water bodies. Coloured materials get into water via natural processes and industrial wastes. Visible colour is characterised by dominant wavelength (D/WL), purity and hue. These characteristics were determined by obtaining the luminous transmittance of wastewater from the kraft pulp and paper mills at Webuye and River Nzoia water samples using a spectrophotometer. The chromophoric materials in the samples were determined at original and adjusted (7.6) pH. It was found that the treated wastewater (DP) contained a higher content of chromophoric materials than both the untreated wastewater (BC) and River Nzoia water (WSC). Seasons did not seem to affect the content of chromophoric materials in treated wastewater as they did in untreated wastewater and River Nzoia water.
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    The efficiency of oxidation ponds at the Kraft pulp and paper mill at Webuye in Kenya
    (Elsevier, 2002) Achoka, J. D.
    Two streams of wastewater from the Kraft Pulp and Paper Mills at Webuye are released from the pulping, bleaching and paper pressing departments. One stream is made up of clear wastewater and the second is made up of turbid wastewater. The wastewaters from the mills are treated using oxidation ponds, after which the treated wastewater is discharged into the River Nzoia. The wastewater was analysed for Cd, Cr, Cu, Ni, Pb, Zn, Ca, K, Mg and Na. The results are that the concentrations of Ca and Na significantly increased in the treated wastewater. The concentrations of Cd, Pb, Zn, K and Mg also increased in the treated wastewater, though not significantly. The concentrations of Cr, Cu and Ni decreased in the treated wastewater but not significantly. Mass loadings of the metals discharged into River Nzoia were calculated. It was found that the mean mass loading of two metals (Ca and Na) significantly increased in the treated wastewater. Five metals (Cd, Pb, Zn, K and Mg) increased in the treated wastewater although not significantly. Three metals (Cr, Cu and Ni) decreased in the treated wastewater but the decrease was not significant. The concentrations of Cd, Cu, Ni, Pb and Zn were all above the limits set by EC for drinking water. These findings pose serious questions of the effectiveness of oxidation ponds system to safeguard the receptor against pollutants from the pulp and paper industry at Webuye.