Journal of the New England Water Works Association, Volume 9

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New England Water Works Association., 1895 - Water-supply
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Page 55 - We can say further at present that the physicians have very generally reported a marked improvement in the health of the people since the filter came into use. The study of this problem and its solution have established with more of certainty than ever before three important points in sanitary science : — 1. The insufficiency of the self-purification of streams. 2. The ready conveyance of typhoid fever down a stream by sewage-polluted drinking water. 3. The practicability of protecting a community...
Page 46 - The question may arise, if water contains so much air why does not nitrification take place in the reservoir? The reason is that nitrification will not take place unless the water with the air comes in contact with certain bacteria which in some unknown way cause the process to be carried on. These bacteria attach themselves to the grains of sand of the filter and remain there, and when air is present they can in a short time cause the nitrifying process to be carried on so completely that nearly...
Page 52 - ... the bacteria in the water applied to it. But the result given to the people is better than this. It appears that with the removal of those parts of the organic matter that are...
Page 90 - The proscenium opening of every theatre shall be provided with a two and one half inch perforated iron pipe, or equivalent equipment of automatic or open sprinklers, so constructed as to form, when in operation, a complete water curtain for the whole proscenium opening, and there shall be for the rest of the stage a complete system of fire apparatus and perforated iron pipes, automatic or open sprinklers.
Page 48 - ... sand which spreads to a width of twenty feet. Upon this rests the filtering sand from four to five feet deep. The valley in the excavation is deepened in the part occupied by the pipe so that the pipe has a slope of one foot in one hundred feet. The pipe was applied as far from the filter-gallery, or conduit in extension of the gallery, as it and the stones surrounding it cost less than the much larger area of stones required to give the desired freedom of flow. Beyond this the large stones were...
Page 51 - ... glazed pipes, in lengths of 30 feet, laid as in the underdrains. This conduit was surrounded by the large stones 2 inches in diameter for a thickness of 4 inches, with layers of decreasing sizes around this, making a total thickness of about 8 inches. Great care was taken to deposit the filtering sand so that the mass should be as homogeneous as possible. It was deposited in two layers. The first layer was covered with planks as fast as laid, upon which the loads were hauled, and these were dumped...
Page 49 - Q expresses the quantity of water in million gallons per acre per day, h the acting head in feet, / the distance flowing through the sand in feet, and d the maximum diameter in millimeters of the finer ten per cent, of the sand grains. This formula expresses quite satisfactorily the quantity of water that will pass through clean sand from which air has been pushed out when the temperature is about 50 Fah., and is convenient to use in comparing sands of different sizes ; but Mr.
Page 46 - ... water in the river, could by a proper inlet be flooded by gravity to a depth of about two feet, thus forming a shallow pond of two and a half acres area, which would gradually filter downward through the sand to the underdrains and be conveyed to the old gallery, and through this to the pumpwell. One of the essential qualities of the design required that the inlet water should be shut off once a day and the pumps kept running until the sand was uncovered and the water within the sand drawn out,...
Page 52 - ... through the filter and consequently the greatest draft from the ground. At the same time there was an increase in the free ammonia of the filtered water, evidently due to the same cause ; but this cause was an exceptional condition due to the surface of the bed not having been cleaned for three months, which will probably not occur again. While the improvement of the water by the removal of the suspended matter and the burning up of the organic matter that was readily oxidizable was very satisfactory,...
Page 46 - ... drawn out, so that the sand could fill with air from top to bottom. This condition of filling the sand with air daily was regarded necessary to insure the burning up of the organic matter which penetrated the sand below the surface and forming nitrates in the water, thus producing conditions the most unfavorable for the continuation of the life of bacteria within the water in their passage through the sand and in the water after leaving the filter. There is nearly air enough in our drinking waters...

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