Experimental Plant
11.105 The experimental plant was disposed of by public tender and some of the associated equipment was salvaged and stored for future use.
11.106
WATER QUALITY CONTROL UNIT
Senior Waterworks Chemist:
D.L. MAKER, C. Chem., F.R.I.C., F.I.W.E.S.
The main responsibilities of the unit are the control of treatment of water at filter stations and the maintenance, by the most economical means, of standards of purity in conformity with international recommendations.
11.107 The unit operates laboratories on the Mainland and Hong Kong Island for the chemical, bacteriological and biological examination of water samples taken daily throughout the supply system from raw water sources to consumers' taps, and for the examination of miscellaneous chemicals and materials connected with the water industry.
11.108
The total number of samples tested was 41,696 (an increase of 5% over last year) of which 1,317 were for other Government departments, commercial and industrial firms and the general public who continued to utilise the unit's services.
Water Treatment
11.109 Much of the territory's supply comes from relatively unpolluted upland resources, and is fully treated by coagulation with alum and lime followed by rapid gravity filtration, pH value correction, sterilisation with chlorine and fluoridation. Additional facilities such as pre-chlorination, sedimentation and activated carbon dosing for taste and odour control are available at filter stations designed to treat raw water derived from poorer quality lowland resources.
11.110 The major part of the unit's resources were concerned with the operation of the most important treatment works at Sha Tin and with extension works increasing its capacity from 795,550 cubic metres per day to 1,091,040 cubic metres per day.
11.111 No serious treatment difficulties were encountered during the year but as an extra precaution against the possibility of virus infection of certain lowland streams special treatment and chlorination criteria were instituted at the relevant stations.
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