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Utilities: Public Works divisions: Related links: |
Bloomington Utility infrastructure historyby William Lloyd, 1960-1994 Utilities Superintendent
Bloomington building boomFollowing World War II, there was an extreme demand for housing across the United States and the Twin Cities area was no exception. The Village of Bloomington had considerable open land on the east side that was relatively level and had a high water table. Such land was ideal for the mass production of housing. Before long, a boom in building began. In 1950, the population of Bloomington was about 10,000; by 1960, the village had grown to about 52,000. Because the community had no water or sewer utilities, each building was provided with a well for potable water and a septic tank cesspool system for waste disposal. In most cases, the well consisted of a length of pipe with a well point attached, driven into the shallow aquifer about twelve to fifteen feet below the surface. The waste disposal systems were positioned just above this. Within a few years, the wastewater from these systems had begun to seep into the aquifer, causing its water to be unfit for drinking. Installation of City's water and sewer systemsIn 1959, after careful study, a referendum was held and voters approved the installation of water and sewer systems for the community. Bloomington hired a consulting engineering firm to design these systems. On the advice of an advisory committee, the Village Council approved a thirty-year water purchase agreement with the City of Minneapolis. In the spring of 1960, a massive crash construction program was initiated. In the first year, approximately 100 miles of water and sewer piping were installed, including a major sewage pumping station. All of the community's wastewater was routed to this station and then pumped through Richfield and Minneapolis to the Pig's Eye treatment facility in St. Paul. Thus Bloomington was able to construct water distribution and sewage collection systems without building its own treatment facilities. All water was to be purchased from the City of Minneapolis and the wastewater was to be treated by the Minneapolis-St. Paul Sanitary District on a contract basis. Components of water systemAt this early stage, there were three major components of Bloomington's water system: a water supply line from the City of Minneapolis, the Valley View elevated tank and the initial stages of transmission piping within Bloomington.
City contracted water supply from MinneapolisThe Minneapolis water supply contract provided for "on demand" water delivery for the first three years. During this startup time, the City of Bloomington was to construct a reservoir and pumping station that would enable the taking of water from Minneapolis during off-peak hours. The Bloomington system could fill its reservoir overnight when the demand on the Minneapolis system was at its minimum and, then, pump the accumulated water to Bloomington consumers during the day as it was called for. To accommodate this procedure, the first of two-10 million gallon reservoirs was constructed in 1964. Through the 1960s, Bloomington made a series of improvements to its water system to facilitate the community's growth. These included building the Western Reservoir, adding a 42-inch supply line, constructing a second reservoir, and adding considerably to the distribution and sewage systems throughout the city. Bloomington Water Treatment Plant addedIn 1969, a water system review indicated that within a few years the water available from Minneapolis would not meet Bloomington's needs. It recommended that Bloomington develop a local water supply and treatment plant. The City Council approved the project in 1971 and the plant was put into operation on May 4, 1974. The plant was originally designed to process six million gallons of water per day, but with subsequent modifications it currently operates successfully at 7.0 million gallons per day. Raw water enters the plant from four deep wells at a hardness of around 320 parts per million (or 19 grains). Slackened quicklime is added to the groundwater to precipitate calcium and magnesium, the elements which account for the water's hardness. The pH is then adjusted by adding carbon dioxide. Chlorine and ammonia are added to disinfect the water as it travels through the distribution system, and fluoride is added to protect teeth. The resulting water is softened to 90-95 ppm of hardness (or about 5.5 grains). The plant has operated a Wet Laboratory since its opening. In it, plant operators run various tests several times each day to ensure that the plant's production meets strict standards. The Water Plant added a second laboratory, the Analytical Lab, in 1993. This lab provides advanced testing of raw and finished water. Among its testing equipment is a graphite furnace/flame atomic absorption which allows analysis of trace metals, such as lead and copper, and a gas chromatograph/mass spectrometer for detection of low-level organic compounds. Tests are conducted on water entering the distribution system, as well as on samples obtained throughout the city. Bloomington's water consistently meets or exceeds all of the criteria established by federal and state regulations and guidelines. For more information, contact: Robert J. Cockriel, Utilities Superintendent
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