Evaluation of water supply system Case study in Naka ... - ENGEES

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Evaluation of water supply system – Case study in Naka, Nigeriagenerator worked for one day but then the injector gets damaged probably because ofpoor quality fuel. Therefore power supply was dependent on the electricity supply bythe Nigerian Electrical Power Authority (NEPA) which was not really reliable: therewas no permanent power supply during the day, and sometimes the power was notenough to run the pumps. However, the Local Government repaired the generator atthe end of July.The treatment was not really efficient and not easy to monitor. Chemicals dosage wasdone manually on a daily-basis because the mechanical dosage system of alum, limeand chlorine went down after one year. Furthermore the water system was notpumping regularly so that it was really difficult to dose accurately. As thesedimentation tank was not covered, during rainy season the coagulation-flocculationsedimentationprocess and the chlorination were disturbed.The pH level was quite low all along the process, around 4.5 to 5.5 at the source andbetween 4.5 and 6.5 at the end of sedimentation tank. This was neither good for themetal assets (corrosion due to acidic water), nor for the coagulation-flocculationprocess (optimal pH from 6.0 to 7.2 when alumic sulphate is used, (South WestWater, 2005)). The pH then lied between 6.5 and 7.2 just after the clear-water tank;apparently lime was poured in this tank until pH reach acceptable level. Colour at theend of the process was nil, but the turbidity was always higher than the target of lessthan 1 NTU.5.2.5 Reliability of the water supplyThe level of services was not reliable, from twice a week to once a month, with alower supply or even no supply at all during the rainy season. This could be partiallyexplained by the fact that during the rainy season, water from rain harvesting andhand dug well usually covered the needs of the households so that they sometimeseven did not look if there was water in the tap, especially people who did not own ayard tap. Moreover, the supply usually stopped after 30 to 60 minutes, theapproximate time to empty the over-head tank, without allowing all the people whowere waiting to fetch water.5.2.6 Convenience of water pointsThe main reasons why people were not using the taps were the distance and thecongestion at the water point. Observation during the taps survey clearly showed thatCranfield University at Silsoe 23 Florianne Bourrigault (2006)
Evaluation of water supply system – Case study in Naka, Nigeriaindividual connections were concentrated in the area around the market place, themost populated one. The public taps were spread in the 4 parts of the town, but theywere too few. Moreover the system did not provide satisfactory pressure as shown inTable 2.Table 2: Level of pressure delivered on the public and private tapsTaps High or Problems Not Nil Totalmoderatepressureofpressureworking atallPublic taps 2 4 6 0 12Individual taps 35 31 18 3 87Total 37 35 24 3 99Women and some interviewed people reported that they did not like the push-up taptype which requires power and the need to stay near the tap, compared to the turningheadtap. However, the push-up type appeared to be more resistant as there were nobreakages of the head in contrast to the turning-head tap; it also avoided waste ofwater through the taps being left opened.5.2.7 Use of water facilities and for what purposesConsumers generally used tap water for every domestic purpose, drinking, cooking,bathing and washing. They did not practice irrigation. The proportion of populationusing tap water was very low, due to the low level of services. Therefore, they used allthe water discharged when it occurred, which did not meet all their needs. Overallsources included, the questionnaire from the STU showed an average consumption of23 litres in dry season versus 40 litres in rainy season for daily consumption percapita. There seemed to be no conflict for water use, as there was no irrigation and nocattle; it was all for domestic use, except those using it for their restaurant or to sellwater in plastic bag.5.2.8 EquityAlmost all the public taps from the initial design in 1998 were either not functional atall or with very low pressure (cf. Table 1); the two functioning with high pressurewere located inside the compound of the private school of MLSC, just near the WTP,which explained the high pressure (connection is just near the pump output to theoverhead tank). Even if households with individual connections often shared tapCranfield University at Silsoe 24 Florianne Bourrigault (2006)
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