Evaluation of water supply system Case study in Naka ... - ENGEES
Evaluation of water supply system Case study in Naka ... - ENGEES
Evaluation of water supply system Case study in Naka ... - ENGEES
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<strong>Evaluation</strong> <strong>of</strong> <strong>water</strong> <strong>supply</strong> <strong>system</strong> – <strong>Case</strong> <strong>study</strong> <strong>in</strong> <strong>Naka</strong>, Nigeriabuy<strong>in</strong>g <strong>water</strong> from <strong>water</strong> sellers dur<strong>in</strong>g the dry season at the rate <strong>of</strong> 20 naira for 20litres; this <strong>water</strong> generally came from the WTP tap or from ponds <strong>in</strong> the dam bed.5.2.3 Water quality at tapA majority <strong>of</strong> the consumers <strong>in</strong>terviewed (70%) were compla<strong>in</strong><strong>in</strong>g about the chemicalodour and taste <strong>of</strong> the <strong>water</strong> supplied, blam<strong>in</strong>g an over dosage <strong>of</strong> chemicals <strong>in</strong> thetreatment <strong>in</strong> the WTP. The manual treatment dosage could expla<strong>in</strong> this problem, but itcould also be a matter <strong>of</strong> habits: the acceptance <strong>of</strong> treated <strong>water</strong> by consumers has<strong>of</strong>ten been a problem <strong>in</strong> develop<strong>in</strong>g countries’ <strong>water</strong> projects because people are notused to the “new” taste <strong>of</strong> this <strong>water</strong> and prefer the usual taste they have from theirtraditional sourcesThe appearance <strong>of</strong> <strong>water</strong> was <strong>of</strong>ten said to be coloured for the first litres dischargedbut good after, especially when <strong>water</strong> had not been discharged for a long time. Thecorrosion state <strong>of</strong> the assets, especially the tanks, comb<strong>in</strong>ed with long stoppages couldexpla<strong>in</strong> this problem.The non-accessibility or non-existence <strong>of</strong> data about faecal coliforms or residualchlor<strong>in</strong>e test<strong>in</strong>g led to only an estimation <strong>of</strong> potential risk rather than a measure <strong>of</strong>contam<strong>in</strong>ation itself. The sanitary survey showed that there are high risks <strong>of</strong>microbiological contam<strong>in</strong>ation (cf. Appendix F). As the <strong>system</strong> was <strong>of</strong>ten down, therewas stagnant <strong>water</strong> <strong>in</strong> the clear-<strong>water</strong> tank and <strong>in</strong> the over-head tank, possibility <strong>of</strong>external <strong>in</strong>trusion <strong>in</strong> the pipes due to the depression <strong>in</strong> the pipe and to the brokenassets. That was made worse by the fact that there was no post-chlor<strong>in</strong>ation.Nevertheless there had been no reported outbreak <strong>of</strong> <strong>water</strong>-related disease the last 2years. There were reported cases <strong>of</strong> diarrhoea which did not lead to death, but nogu<strong>in</strong>ea worm, nor cholera; but this might be because cases were not reported becausepeople do not always go to a health centre. There were cases <strong>of</strong> bilharziosis,especially among children, reflect<strong>in</strong>g a problem <strong>of</strong> bath<strong>in</strong>g <strong>in</strong> the dam and streams, orwalk<strong>in</strong>g bare foot <strong>in</strong> stagnant <strong>water</strong>.5.2.4 System performance at WTPAt the WTP, one major problem was the power <strong>supply</strong>. The diesel-generator had notbeen work<strong>in</strong>g for many months. The battery was changed around May 2006 and theCranfield University at Silsoe 22 Florianne Bourrigault (2006)
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