Procurement News Notice |
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| PNN | 206 |
| Work Detail | Five years ago, St. Peter was able to increase its water utility's total capacity from 2 million to 3.3 million gallons per day and deal with nitrate and radium problems at the same time. The system's reverse-osmosis process resulted in softer water moving through the pipes in homes, an extra benefit for the town's 11,000 residents and the Gustavus Adolphus College campus. Construction on the Broadway Avenue plant began in September 2009 and was completed in March 2011. The Jefferson plant kept operating during this period, and the Saint Julien plant was also continued while the building to house the reverse-osmosis equipment was being constructed. The plant on Broadway Avenue provides high-quality drinking water from a groundwater source. Its nine wells range in depth from 130 to 780 feet and draw water from several aquifers. A 2006 water master plan indicated a need to expand St. Peter's water system’s capacity. The town had been using seven wells, that drew water from the Jordan, Franconia-Ironton-Galesville and Mount Simon-Hinckley aquifers. The wells fed two iron-and-manganese treatment plants — the Jefferson plant, built in 1949, and the St. Julien plant, constructed in 1988. For many years, the state hospital in St. Peter had its own water supply. In 2003, problems developed with the wells, which prompted the center to connect to the city’s public water supply. At that time, St. Peter was experiencing a steady population growth along with the addition of commercial customers. The town also had become home to three long-term care facilities. The planned upgrade included the sealing of two multi-aquifer wells and the drilling of four new wells, two into the Mount Simon-Hinckley aquifer, one into the Jordan, and one into the FIG aquifer. It became clear that, upon evaluation of the water quality from these formations, the utility would need to upgrade its treatment process as well. The water utilities superintendent for St. Peter Public Works reported levels of nitrate found in the well drilled into the Jordan aquifer were double the levels from the two existing Jordan wells, and blending with water from other wells might not be enough to keep the nitrate in the finished water from exceeding the federal limit of 10 parts per million. An engineering study also indicated that expanding the existing filtration plants would not be sufficient. The city decided to construct a new facility on Broadway Avenue with gravity and membrane (reverse-osmosis) filtration and to modify the St. Julien plant with the addition of reverse-osmosis treatment. In addition, plans were made to demolish the Jefferson plant. The gravity-filtration stage at the plant has a capacity of 2,100 gallons per minute and consists of four concrete filter cells, each with a surface area of 225 square feet and each containing filtering layers of anthracite and manganese materials. Reverse osmosis offered a way of balancing parameters regarding the wells, since the two into the Mount Simon yielded a large amount of water but also iron and manganese, radium (gross alpha), chloride and sulfate levels. The FIG aquifer, which had a smaller yield, also contained dissolved solids, iron and manganese. The well in the Jordan aquifer, also with limited yield, was low in iron and manganese but contained the higher level of nitrate. As was the case with the Jefferson and Saint Julien plants, water from the wells goes into separate plants and is blended in the distribution system. About 85 percent of the water goes through the reverse-osmosis membranes. The reverse-osmosis system at the Saint Julien plant, a building constructed adjacent to the existing plant, operates in a similar fashion. A total of 1,060 gallons of water per minute is blended with 150 gallons per minute of gravity-filtered water. The modifications to the plant included the replacement of some of the piping and the installation of chemical-feed systems similar to those at the Broadway Avenue plant. The total project cost was $18.8 million with some of the money coming through below-market loans through the drinking water revolving fund in addition to some grant money through the American Recovery and Reinvestment Act. Tours of the St. Peter’s state-of-the-art reverse osmosis water treatment plant at 1312 West Broadway were offered Saturday in conjunction with the Smithsonian Institute’s Water/Ways traveling exhibit on display at Traverse des Sioux Treaty Site. |
| Country | Vatican City State (Holy See) , Southern Europe |
| Industry | Water & Sanitation |
| Entry Date | 02 Sep 2016 |
| Source | http://www.mankatofreepress.com/news/local_news/reverse-osmosis-the-response-to-st-peter-s-need-for/article_9496a092-6d3d-11e6-ac22-abe6e25e8ddb.html |
