11.112 A survey of pipe test pieces in the distribution systems of salt water flushing supplies indicated that chlorination at intake pumping stations at existing dosages has curtailed, but not entirely suppressed, fouling by marine growths to a reasonably constant and acceptable level.
11.113 Average dosages and total consumption of principal chemicals used in water treatment are shown in Appendix CC. Despite the increase in water consumption over the previous year the actual cost of chemicals purchased fell slightly, reflecting a greater stability in prices and economies achieved in dosing levels.
Quality of Supply
11.114 The quality of supply, which is characteristically soft and low to moderate in total mineral content, continued to be generally satisfactory. Fluctuations were much less pronounced than in recent years as the residual salinity in Plover Cove reservoir fell to around 80 ppm as sodium chloride, which was close to the predicted long-term minimum.
11.115 Routine samples from consumers' taps indicated that bacteriological purity was the highest yet achieved and well above that recommended by the World Health Organisation. Information on principal water quality characteristics is given in Appendix CC.
11.116 Arising from complaints of discoloured water, tests were carried out jointly with the Architectural Office using a chemical inhibitor to reduce serious corrosion of galvanised iron pipes in the centralised hot water systems of some Government buildings. The tests proved successful and treatment equipment was installed subsequently.
General
CONSULTANTS LIAISON UNIT
Senior Engineer:
LEUNG Kwok-wai, B.Sc.(Eng.), M.I.C.E., M.I.W.E.S.
LEUNG Tat-ming, B.Sc.(Eng.), M.I.C.E.
IP Yun-wing, M.Sc.(Eng.), B.E., M.I.C.E., M.I.E.Aust. (Acting)
11.117 The Unit is responsible for liaising with consulting engineers engaged on water supply schemes other than desalting. Expenditure during the year amounted to about $178 million.
High Island Water Scheme
11.118 Satisfactory progress was maintained in the construction of the West Dam to the High Island Reservoir and the dam reached a level of +22M P.D. At the East Dam, leakage through the foundation of the East Sea Cofferdam was partially confined and foundation excavation for the
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11.112 A survey of pipe test pieces in the distribution systems of salt water flushing supplies indicated that chlorination at intake pumping stations at existing dosages has curtailed, but not entirely suppressed, fouling by marine growths to a reasonably constant and acceptable level.
11.113 Average dosages and total consumption of principal chemicals used in water treatment are shown in Appendix CC. Despite the increase in water consumption over the previous year the actual cost of chemicals purchased fell slightly, reflecting a greater stability in prices and economies achieved in dosing levels.
Quality of Supply
11.114
The quality of supply, which is characteristically soft and low to moderate in total mineral content, continued to be generally satisfactory. Fluctuations were much less pronounced than in recent years as the residual salinity in Plover Cove reservoir fell to around 80 ppm as sodium chloride, which was close to the predicted long-term minimum.
11.115 Routine samples from consumers' taps indicated that bacteriological purity was the highest yet achieved and well above that recommended by the World Health Organisation. Information on principal water quality characteristics is given in Appendix CC.
11.116 Arising from complaints of discoloured water, tests were carried out jointly with the Architectural Office using a chemical inhibitor to reduce serious corrosion of galvanised iron pipes in the centralised hot water systems of some Government buildings. The tests proved successful and treatment equipment was installed subsequently.
General
CONSULTANTS LIAISON UNIT
Senior Engineer:
LEUNG Kwok-wai, B.Sc.(Eng.), M.I.C.E., M.I.W.E.S.
LEUNG Tat-ming, B.Sc. (Eng.), M.I.C.E.
IP Yun-wing, M.Sc.(Eng.), B.E., M.I.C.E., M.I.E. Aust. (Acting)
11.117 The Unit is responsible for liaising with consulting engineers engaged on water supply schemes other than desalting. Expenditure during the year amounted to about $178 million.
High Island Water Scheme
11.118
Satisfactory progress was maintained in the construction of the West Dam to the High Island Reservoir and the dam reached a level of +22M P.D. At the East Dam, leakage through the foundation of the East Sea Cofferdam was partially confined and foundation excavation for the
170
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