MARENGO – City officials still are developing a plan to salvage their $12 million upgrade to the aging wastewater treatment plant, while they brace for a one-year construction delay and looming project changes.

Officials from Marengo and the Illinois Environmental Protection Agency confirmed that the long-awaited plant upgrade will be downsized or relocated to an area that has better soil than the project’s current location, northeast of the existing plant along Route 23, near the Kishwaukee River.

Marengo halted the project Sept. 5, after learning from the construction firm, J.J. Henderson, that an old landfill underneath the expansion site contained solid waste that would complicate construction and significantly add costs to the $12 million project.