Construction has begun on a nearly $400-million wastewater treatment infrastructure project at the Metropolitan Water Reclamation District of Greater Chicago’s (MWRD) Terrence J. O’Brien Water Reclamation Plant in Skokie.

The MWRD broke ground Oct. 8 on Battery E, a four-year project that will add aeration tanks, final settling tanks, ancillary structures and supporting equipment to the nearly century-old facility.

The project also includes an enhanced biological phosphorus removal process designed to reduce phosphorus concentrations in treated wastewater before it is discharged into the North Shore Channel.

The investment is among the largest the MWRD has made on a single project in its 137-year history. The O’Brien plant treats wastewater from surrounding communities, serving more than 1.3 million people and helping protect regional water quality.

“As the O’Brien Water Reclamation Plant approaches 100 years of service, we are making an investment that will help ensure this facility is prepared for the decades ahead of protecting public health and our waterways,” MWRD President Kari K. Steele said in a statement.

The project will help the district meet new phosphorus discharge limits taking effect in 2027, with stricter requirements scheduled for 2030.

Excessive phosphorus in waterways can contribute to algae growth, deplete oxygen levels and harm aquatic ecosystems. The North Shore Channel connects to the North Branch of the Chicago River and the wider regional waterway system.

Battery E will use naturally occurring microorganisms to remove phosphorus during wastewater treatment. The additional capacity will also allow the district to take existing treatment infrastructure offline for rehabilitation.

Three of the plant’s four existing treatment batteries are approaching 100 years old. The MWRD plans to upgrade Batteries A, B and C in phases beginning in 2031, bringing the infrastructure up to modern standards and incorporating biological phosphorus removal capabilities.

The district began related process improvements in 2023 with work on Battery D, including a sidestream fermentation zone and supporting infrastructure. That work is expected to be completed in 2026.

The MWRD also awarded a contract in 2025 for a chemical backup system to provide additional support in meeting phosphorus discharge requirements.

Commissioner Cameron Davis said the project would benefit water quality while supporting employment.

“It’s a big investment in the health of our waterways, jobs, and helping our downstream neighbors,” Davis said.

Battery E is expected to create work opportunities for skilled trades, including electricians, ironworkers, labourers, millwrights, operating engineers, pipefitters, plumbers, steel erectors and truck drivers.

The O’Brien plant opened in 1929 and treats wastewater before returning the treated water to the North Shore Channel. The new infrastructure is intended to increase treatment capacity, support modernization and address changing wastewater flows, weather patterns and nutrient-removal requirements.

Source:  https://www.chicagoconstructionnews.com/400m-wastewater-treatment-project-breaks-ground-in-skokie/