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from the Rapid Gravity filters and it was found possible to pass this water through the existing slow sand filters. This represents a considerable saving, as approximately 2% of the total output is required for sand washing, i.e., 200,000 gallons per day at maximum output.
186. Water Analysis. The purity of the supply was maintained at a high standard, with the exception of a period in May-June when the Peak mains became contaminated. The contamination, which was never satisfactorily tracked down, affected many of the mains in the Mount Kellett and Mount Gough areas, and was only eliminated after working systematically through the whole system. It is considered most probable that the contamination entered the system through the leaking roof of Mount Gough Service Reservoir, which has since been thoroughly cleaned and repaired. Apart from this local contamination, the reports were normal.
187. Of the samples taken at service reservoirs, two showed B. Coli in 10 c.c. or less. One was on the Peak during the period referred to above, and the other was shown to be due to a dirty sampling tap. Only three other samples were below the standard of B. Coli absent in 100 c.c., two showing present in 100 c.c. and one present in 50 c.c. The overall percentage was 98% of samples showing absence in 100 c.c.
188. Tap samples were 94% free of B. Coli in 100 c.c., and 23% of the bad samples were taken during the Peak epidemic. Chemical and physical analysis continued to be 100% satisfactory. Sampling and testing were carried out by the Government Pathologist and Chemist, respectively.
189. Pumping. Water pumped during the year amounted to 2,091 million gallons of raw water and 1,882 million gallons of filtered water. This showed a considerable saving over the previous year, as, although overall consumption was down by 4.5%, pumping was down by 27%, being attributed to more
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