The expanded wastewater treatment plant in Carbondale, Illinois, was one of the first major projects in the state required to comply with new antidegradation regulations that were adopted by the Illinois EPA in 2002. CMT provided facilities planning, design, and construction phase services to expand the facility to meet 2024 population projections, while saving the city 33 percent in energy costs to operate it.

A facility plan was prepared to qualify for financing through the State Revolving Fund Loan Program. During the planning phase, CMT met with IEPA to discuss conversion of existing tertiary lagoons into flow equalization basins for storage during excess flow events. CMT also overcame the challenge of reusing existing treatment plant components both upstream and downstream of the new treatment processes, despite the existing flat hydraulic profile. New processes were designed to alleviate the hydraulic problems, while allowing for future construction of tertiary filters.