Water-supply paper Volume 293

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 Excerpt: ...at which the water is delivered, and 1 foot at the end where it is taken out. From the settling basin the water flows through a flume over a weir into the coagulating basin with a capacity of 300,000 gallons, at whose entrance it is met by the coagulant solution. From 2 to 5 grains of sulphate of alumina to" the gallon is used, the amount depending on the condition of the raw water. The alkalinity is tested daily. The filter alum is dissolved in tanks into which air is blown under pressure through pipes at bottom. The solution flows by gravity to a lead-lined centrifugal pump, by which it is lifted to an upper tank, which overflows into the bottom tanks, from which it is fed by gravity into the water in the coagulating basin. This method is believed to keep the solution at uniform strength and insure a uniform head. The water in the coagulating basin is given three hours for the completion of the process, and is then pumped under pressure through the filters into the main distribution. Each of the 10 horizontal filter shells is 32 feet long and 7J feet in diameter. Each shell is divided into two compartments, hi each of which are 5 feet of sand. The filter shells are capable of sustaining a pressure of 200 pounds to the square inch. The bacterial efficiency is reported to range from 96 to 99.06, the percentage increasing with the number of bacteria in the raw water. An upper and lower distributing service is employed. The lower service is supplied from the river station, winch is designated station No. 1, and serves, under direct pressure, the business section of the town and that along the flood plain of the river. At station No. 2 the filtered water is pumped into a reservoir and the mains are so arranged that the pumps can be brought into commission...