The Purification of Public Water Supplies

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D. Van Nostrand Company, 1898 - Water - 304 pages
 

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Page 104 - Bacillus coli, justifies one in concluding that the water under consideration has been polluted by intestinal evacuations from either human beings or animals. Waters so exposed as to be liable to such pollution should never be considered as other than a continuous source of danger to those using them.
Page 240 - Worms, it appears that the efficiency of the two systems of filtering, which are there worked side by side, are practically identical, so far as regards their effect upon the chemical purity of the water, but the percentage of bacteria left by the Fischer process is somewhat greater than is left by the sand filter when clean and in good working condition. This, however, is not considered a defect of practical importance. The water delivered by the new filters at Worms, as well as at the other places...
Page 53 - This condition is the amount of rainfall higher up the river, or, in other words, the volume of water flowing along the river-bed. The interesting observations of Dr. Marshall Ward leave no doubt that sunlight is a powerful germicide ; but it is obvious that its potency in this respect must be greatly diminished, if not entirely annulled, when the solar rays have passed through a stratum of water of even comparatively small thickness before they reach the living organisms ; and the author shows,...
Page 36 - ... St. Louis, 39. Average, 58. Cities using filtered water— London, 14.4; Berlin, 7.1; Rotterdam, 5.7; Hamburg (filters put in service May, 1893), 9.7. Average, 9.1. But there are no more striking examples than those of Lawrence and Lowell, Massachusetts: "The city of Lawrence, with a population of 55,000, draws its water supply from the Merrimac River, after it has received the sewage from Lowell, nine miles above. The city of Lowell, with a population of 85,700, draws its water supply partly...
Page 120 - ... disease germs and the toxic properties in a polluted water. 3. Even if a satisfactory filter was obtainable, it is doubtful if the average householder would give this the attention it would require to keep it at all times in condition to act as a safeguard. In view of which I have reached the conclusion that if the consumer is to have a safe drinking-water, it must come to him in this condition through the public water - mains. In other words, the matter of purity must be looked after by the...

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