Albany takes its supply from the raw Hudson River water through screened intakes and passes it through two 18-inch inlets and one 36-inch inlet into a sedimentation basin. After sedi mentation, it passes roughing filters into the slow sand filters where the daily rate of filtra tion is 3,000.000 gallons per acre. It then passes into the covered filtered water reservoirs. its capacity is 21.000.000 gallons per day and its bacterial efficiency is 99 per cent. The usual bac terial efficiency of slow sand filters ranges from 98 to 99 per cent.
Chicago obtains its daily supply of 1,000.000, 000 gallons from Lake Michigan, through nine intake tunnels, reaching seven intake cribs two or more miles from shore.
In 1915 the Chicago Board of Experts re ported that its water from Lake Michigan was turbid, polluted and unsafe for drinking pur poses. The opening of the Drainage Canal in 1901 to send the flow of sewage down the Illi nois River lessened the pollution of near shore lake waters, but did not wholly remedy the diffi culty. City sewage still flows to a limited ex tent into the lake and pollution continues. The problem is a serious one for Chicago as it is for all other cities similarly situated. The in takes of other Great Lake cities, however, are not so near the effluents of their sewage and there is less direct pollution therefrom. Chlori nation was tried in one of the districts in Chicago in 1912, and was attended with good results, except that during the winter months the plant was affected by the severe cold. Un doubtedly Chicago will adopt some modern process for the sterilization of its water supply.
In Milwaukee hypochlorite has been used to eliminate gas-forming bacteria from its Lake Michigan supply, but such large dosages were necessary, that the taste was affected and odors were produced. The water before treatment contained 2,590 microbes per cubic centimeter. Milwaukee's consumption in 1915 was 48,000,000 gallons a day, which was equivalent to 111 gal lons per capita.
Cleveland in 1911 completed its new intake and a marked improvement followed. It in stalled a rapid sand filtration plant and also used calcium hypochlorite as a germicidal dis infectant. Its supply in 1912 was at the rate of 133 gallons per capita a day.
Superior, Wis., has a slow sand filtration plant comprising three units with a total capac ity of 300,000 gallons a day.
Kansas City, Missoun, obtains its supply from the Missouri River at Quindaro above the inflowing polluted Kansas River. The raw Mis
souri River water is pumped into a reservoir of 90,000,000 gallons capacity at Quindaro where there is preliminary sedimentation. The water is thereafter treated with alum and lime. The dear water then returns to the pumping station and is treated in its passage with calcium hypo chlorite and aerated. It is then pumped into Turkey Creek reservoir, where a high pressure service is maintained and thence it is let into the mains. The raw river water in 1911 contained as high as 30,000 B. toll per cubic centimeter and they were reduced by such treatment as stated to less than 100 per cubic centimeter, which is the standard of purity established in 1914 by the Treasury Department of the United States Gov ernment. The purification at Kansas City, Mo., whereby large colonies of pathogenic bacteria in its raw river water supply were eliminated, well illustrates how Missouri River water may be purified and made safe for potable uses.
Buffalo obtains its supply from Lake Erie and it is purified by chlorination at the intake pier in Lake Erie. The daily consumption is approximately 125,000.(XX1 gallons.
New Orleans obtains its supply from the Mississippi River. A Sewerage and Water Board was created in 18)9 and aerial cisterns were ordered closed Thcy were breeding places of the sscgomyur which cause yellow fever. In 1909 a new rapid sand filtration plant was in stalled having a daily capacity of 40,000,000 gallons and the water was first put through sedi mentation aided by sulphate of aluminum and ferrous sulphate as coagulants. In 1910 the rate was 5.99 million gallons per acre per day. New Orleans has two filter plants, namely the Car rollton Filters and the Algiers Filters. From an official report it appears that the rate of filtration through the former in 1914, was five fold that of the latter. In 1915 the daily con sumption was 20,000,000 gallons, which was at the rate of 57 gallons per capita, Omaha, Neb., obtains its supply from the Missouri River which requires purification. Ac cordingly a series of basins were constructed for sedimentation of much of the suspended matter. That was accompanied by coagulation the use of alum. There is also used hypochlorite without filtration. Since the installation of the foregoing processes of puri fication, there has been a great reduction in typhoid and other diseases produced by patho genic bacteria.