Problem: Provide new water supply, treatment, and storage facilities to serve the new Thornwood Development and other growth areas in South Elgin, Illinois. Existing area deep wells contained elevated concentrations of barium and radionuclides (radium 226/228 and gross alpha). Discharge limits of the local wastewater authority limited disposal of barium containing water treatment wastes to the sanitary sewer.
Solution: A unique interactive well drilling process was used to optimize raw water quality (particularly with respect to barium), while insuring sufficient well capacity. Minimizing barium in the raw water supply substantially reduced project costs by eliminating the need for expensive regenerant wastewater treatment required to meet barium discharge limits of the local wastewater treatment authority.
Improvements included two 1,000 gpm, 1,970 feet deep Mt. Simon sandstone wells; six 9-foot diameter ion exchange softeners for reduction of radioactivity (gross alpha, combined radium 226 and 228) and hardness; a 2.0 million gallon stand pipe; three 2,500 gpm high service booster pumps; brine storage tanks and pumps; waste backwash storage tanks and pumps; and an inline booster pump station/pressure reducing station, which provides an emergency interconnection with the Village of South Elgin.
In the interactive well drilling program, sandstone aquifier formations were individually blocked off during the drilling process to determine the quantity and quality of water available from each aquifier.
As a result of the interactive well drilling program, a liner was installed in the wells to seal off the Ironton Galesville sandstone formation, while leacing the Mt. Simon sandstone formation open. Although treatment for the radium removal would still be required, the regenerant waste water could be discharged to the sanitary sewer without treatment to remove barium from the waste stream. The interactive drilling program resulted in significant project cost savings over other possible alternates examined. The design of the water treatment facility also took into consideration other needs of the community, including: 1.) the provision of facilities for local police units at the water treatment building, 2.) coordination with needs of new fire station to be constructed on the same site, and 3.) the complementary appearance of the water treatment facility due to its proximity to neighboring residencies.