Abstract

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Abstract The bacteriological quality of treated piped water in distribution system in Ilorin metropolis was assessed. The pH, suspended solid and microbiological characteristics (heterotrophic bacteria count and coliform count) of treated water collected from thirty different locations within the metropolis were determined. The samples were slightly acidic (pH 5.16 to 6.53); the suspended solid content was low (3-OxlO"4 to 6.5xl0"3 mg/ml) but the bacterial counts were high (l.OxlO4 to 2.25xl05 cfu/ml); the coliform count varied between 0 and 19cfu/ml. In all 11 bacterial species were encountered; Bacillus subtilis Enterobacter aerogenes Micrococcus luteus were the predominant organisms. Each samples contained between 3 and 7 bacterial species. The results suggest that the treated water sometimes fall below the WHO bacteriological standard required of drinking water. Post-treatment contamination especially, breach of distribution network's integrity is suspected. The study highlights the need for regular surveillance of the water distribution system

Keywords: distribution network, drinking water, contamination, surveillance