Illinois NLRS Program and Project Narratives

The Metropolitan Water Reclamation District of Greater Chicago, MWRDGC, provides wastewater treatment and stormwater management services for residents and businesses in the Chicagoland area. Its service area covers 882 square miles, including the city of Chicago and 128 suburban communities in Cook County. MWRDGC serves approximately 12.72 million people each day, which includes 5.19 million residences. 

MWRDGC operates seven water reclamation plants, WRPs: Stickney Water Reclamation Facility, Calumet WRP, Terrence J. O’Brien WRP, John E. Egan WRP, James C. Kirie WRP, Lemont WRP, and Hanover Park WRP. Due to the large volume of discharged water from these facilities, their nutrient contributions often comprise a large percentage of the annual statewide loads. Case in point: in 2021, the facilities collectively discharged approximately 411 billion gallons of treated water and approximately 5.2 million pounds of phosphorus; in 2022, the facilities collectively discharged approximately 435 billion gallons of treated water and approximately 4.9 million pounds of phosphorus. Together, MWRDGC facilities contributed 42% of the annual statewide total phosphorus point source loads in 2021 and 2022. Table 5.8 shows the annual total phosphorus loads from the seven MWRDGC facilities for baseline 2011 and 2018-22. 

In 2020, the total phosphorus discharged from MWRDGC facilities was 6.3 million pounds. Most of the reduction since then can be attributed to nutrient removal technology operations at the Stickney facility. In 2012, the facility implemented a biological phosphorus removal system in one battery. All batteries were completed in 2014, and the system was optimized by 2018, resulting in a 95% phosphorus removal efficiency. However, issues arose with managing solids content at the WRP in January 2019. The biological phosphorus removal operation was halted and slowly restarted in 2020. In 2021, a temporary chemical phosphorus removal system was installed to ensure compliance with the permit limit of 1 mg/L that went into effect in August 2021. A permanent system is scheduled for completion by 2024. 

The Calumet WRP discharged the highest statewide total phosphorus load in 2022. A phosphorus removal feasibility study was completed in 2019 and a chemical removal process is currently being constructed, though a biological removal system is still being evaluated. The Calumet facility’s current National Pollutant Discharge Elimination System NPDES permit includes a schedule for achieving compliance with a total phosphorus limit of 1 mg/L by January 1, 2024. 

The O’Brien WRP is MWRDGC’s third-largest facility. A phosphorus removal feasibility study was com­pleted in 2019. A pilot test using algae for nutrient removal was completed as a possible polishing process. A small-scale side-stream enhanced biological phosphorus removal, or S2EBPR, system study was initi­ated in 2020. Currently, Battery D is being redesigned for S2EBPR, and Battery E — a new battery with S2EBPR — is being constructed. The facility’s current NPDES permit includes a schedule for achieving compliance with a total phosphorus limit of 1 mg/L by August 1, 2027. 

Significant reductions in total phosphorus loads from point sources are anticipated once all seven of these facilities, along with other large major municipal facilities throughout the state, meet a 1 mg/L and 0.5 mg/L total phosphorus concentration. 

Table 5.8. The Metropolitan Water Reclamation District of Greater Chicago facilities’ annual total phosphorus loads