FILTRATION PLANT AT MINNEAPOLIS
The Minneapolis, Minn., filtration plant, located on Columbus Heights on the East Side of that city, is conceded to be one of the two most important possessions of that section of the city, the other being the pump house on the river bank. This filtration plant has demonstrated by more than a year’s service that it is one of the best of its type. The daily water supply of Minneapolis, 25,000,000 gallons, passes through this plant, which was built at a cost of $1,500,000, after a typhoid epidemic in the city had called attention to the need of means to reduce the danger of infection from the water supply. The time of actual construction of the plant was eighteen months. The plant stands on the highest land around Minneapolis and is three miles away from the pump house. An improved water supply for the city has been agitated for the last quarter of a century and the project was discussed by City Engineer F. W. Cappclen when the American Water Works Association met in that city in 1895. In 1904 the proposition was taken up in earnest. A commission to investigate the feasible methods for an improved water supply was appointed, the commission consisting of Engineer Cappelen, City Engineer Andrew Rinker and Allen Hazen, of New York, consulting engineer. After they presented their report to the City Council the present system was adopted. The buildings are fireproof and 98 per cent, of the total work was done by the day labor system. The clear water basin has a capacity of about 45,000,000 gallons. The mechanical equipment of the plant includes a rock crusher for crushing lime, two lime mixers of forty cubic feet capacity each, an electric elevator of 6,000 pounds capacity, bucket elevator for ten tons’ hourly capacity, vacuum cleaner of eighty-five cubic feet displacement, twenty-four centrifugal pumps ot one-quarter to fifty horse-power capacity, two trolley systems for handling chemicals, gas plant to supply thirty burners, three ventilating fans—one run by fifty horse-power steam engine, others by motors—twelve marble operating tables costing $8,000, and brass wire screens and bronze strainer plates costing $9,500. Completely equipped chemical and bacteriological laboratories are installed for the use of the operators. The centrifugal electric pump at the station does more work than old-fashioned steam pumps many times its size. This pump will suck the water from the river and force it three miles to the filtration plant. The water passes through two reservoirs and layers of sand and gravel before reaching the city mains. In the first reservoir it is treated with two grains of alum to a gallon. The solution is removed by sand and gravel filters. Leaving the filters, the purified water enters a big clear-water basin, where it remains at low temperature.