of reducing dental decay in children was temporarily reduced for 5 months, resulting in a lower average level of fluoride at 0.7 parts per million compared with a nominal target of 1.0 parts per million.
10.73. Close control of bacteriological purity of supply throughout the distribution system was maintained and overall results of sampling continued to be very satisfactory, comparing favourably with those achieved elsewhere. The ideal standard aimed at is absence of coliform organisms in 100 millilitres of sample. Of 2,553 regular samples taken from service reservoirs outlets 99.1% conformed to this standard. Random samples were also taken from consumers' premises and public standpipes. 99.3% of the 1,424 samples from taps connected directly to mains and 97.7% of 1,240 samples taken from taps fed via private storage tanks were free from coliform organisms. There has been a notable improvement in the quality of tap samples over the last 3 years, possibly reflecting greater care by the public in the maintenance of private storage tanks and service reservoirs.
10.74. As a precautionary measure chlorination of all supplies was temporarily increased during the cholera outbreak in July.
CONSULTANTS' LIAISON UNIT
Senior Engineer:
S. K. KWEI, B.Sc.(Eng.), C.Eng., M.I.C.E.
General
10.75. The unit is responsible for liaison with the consulting engineers working on water supply schemes for the Hong Kong Government. Expenditure on works during the year amounted to about $16 million.
Plover Cove Scheme
10.76. The installation of the valves and pipework to integrate the draw-off of water from the Jubilee Reservoir with the releases from the Plover Cove Scheme was completed. Take-over tests were successfully concluded on the Stage II supervisory control and instrumentation plant.
10.77. Repairs were carried out to the Tai Po Tau fabridam which was seriously damaged and put out of commission on 28th April.
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