Treatment efficiency of water produced at the Kwanyaku water treatment plant in the Agona District of the Central Region and distribution line contamination

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October, 2015
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A study was conducted to assess the treatment efficiency of water produced at the Kwanyaku Water Treatment Plant and Contamination in the distribution system. The physico-chemical and bacteriological quality of water from the raw water to the final treated water and three selected locations along the distribution chain were analysed. Raw water, Settled water, Filtered water, Final water and randomly selected water in three locations along the distribution chain were sampled and examined for thermotolerant coliforms (TTC) using the most probable number method (MPN). The pH and alkalinity values for all the water samples were within the recommended limit of 6.5 -8.5 and 200 mg/l respectively. Colour and turbidity values except of that for the raw water were also within the WHO range of 0 -15 HU and ≤ 5 NTU respectively. Total Hardness, Calcium Hardness, Calcium, Magnesium Hardness, Magnesium, chloride and conductivity for raw to final water samples were all within the WHO acceptable limit of 0-500 mg/l, ≤ 200 mg/l, ≤ 80 mg/l, ≤ 30 mg/l, 50-150 mg/l, ≤ 250 mg/l and 300 μS/cm respectively. All Raw water samples were positive for TTC. The mean value of MPN per 100 ml of Raw water was 220. However, the three distribution locations sampled recorded low levels of residual chlorine, with temperature and indicator bacteria (TTC) above those of the WHO guideline. There were significant differences between residual chlorine values recorded in the Final water at the treatment plant site and those recorded for the water at the three distribution points. Residual chlorine was less than the WHO limit of 0.6 mg/l in the distribution samples making it prone to bacterial growth.Temperatures increased along the distribution chainfavouring growth of biofilms in the water. Recontamination of the treated water occurred along the distribution chain and this could be as a result of bursts along the distribution chain, high temperature and low chlorine residual coupled with poor monitoring and maintenance practices. The efficiency of treatment was 100% as the quality of water produced at the Kwanyaku Water Treatment Plant met the international standard recommended by World Health Organisation (WHO). However water samples along the distribution chain revealed that the quality of the water degrades before getting to some of the consumer points, hence more work need to be done in maintaining the quality up to all the consumer points.
A thesis submitted to the Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements Master of Science degree in Environmental Science, 2015