Lake County Gazette

Lake Forest has agreed to pay Northern Divers U.S.A. a sum of $225,000 for the cleaning of water plant intake pipelines that transport raw water from Lake Michigan to the Water Treatment Plant for filtration. It should be noted that Northern Divers undertook similar cleaning tasks in 2021 and 2018.

According to the agenda of the March 18 Lake Forest City Council, Northern Divers' patented cleaning process allows the plant to continue operations during the cleaning phase. This procedure does not necessitate the removal of the chemical feed system that extends along each intake's entire length. If there had been a need to remove or replace this system, it would have incurred an additional cost of $350,000 for the city.

The council's agenda also revealed that the 24-inch intake pipeline was constructed in the 1930s and is made of sand cast iron. This pipeline extends approximately 2,975 feet into Lake Michigan with three inlets. In contrast, the 42-inch intake pipeline, constructed in 1974, is a pre-stressed concrete pipe extending 3,900 feet into the lake. Both pipelines are situated at an approximate depth of 30 feet along the lake's bottom.

The agenda of March 18 Lake Forest City Council further states that increased sediment accumulation at the bottom of these intakes became a significant issue during peak demand due to water impurities. This can lead to doubling backwash frequency and potentially increasing water volume by up to 20%. Such occurrences result in higher operational costs, capacity reduction, and other related issues.

Finally, according to Lake Forest City Council's agenda on March 18th, Northern Divers has experience cleaning intakes at various locations including North Chicago, Abbott Laboratories, Glencoe Water Plant, Waukegan Water Plant, Great Lakes Naval Base plant and Thermal Chicago Inc.'s water intakes in Chicago.