The Metropolitan Water Reclamation District of Greater Chicago (MWRD) Board of Commissioners recently approved plans for a unique research project looking to optimize the water reclamation process. 

The project will assess energy efficiency, phosphorus removal, and improved activated sludge settling known as densification. Titled “Balancing Carbon Management, Energy Management, Energy Production, Nutrient Removal, and Densification,” the project is supported through public and private contributions and a Water Research Foundation (WRF) “Tailored Research Collaboration” grant. The project takes a holistic look at these interconnected factors so the wastewater treatment process can be optimized appropriately.

“This cutting-edge research will help inform future process decisions at the MWRD as well as wastewater treatment utilities seeking to discover new efficiencies in managing water and recovering resources,” said MWRD President Kari K. Steele. “We look forward to gaining more knowledge through this study that will help us charter a more sustainable future.”

The MWRD research staff, with support from partners Black & Veatch and Wastewater Microbiology Solutions, plan to pilot test a series of primary and secondary treatment scenarios at the MWRD’s Egan Water Reclamation Plant (WRP) in Schaumburg. As a first stage in wastewater treatment, primary treatment controls the amount and type of carbon that is removed and directed to either anaerobic digestion for energy recovery or to the secondary treatment activated sludge process for treatment. Over 24 months, pilot reactors will be used to test and quantify key performance indicators to assess the benefits and tradeoffs of directing influent carbon to energy production or nutrient removal and the role this plays in activated sludge densification. By collecting this data, MWRD officials said it can better inform future investments at WRPs. 

“This study in water reclamation plant innovation will help our future infrastructure decisions that lead to more sustainable and efficient treatment processes while helping us improve our water environment,” said MWRD Commissioner Daniel Pogorzelski. “We thank the Water Research Foundation, our partners at Black and Veatch, and our staff for their valuable contributions to this study.”

Phosphorus removal from the wastewater helps to reduce nutrient levels in the discharge to within permit limits and improves water quality downstream. Preventing nutrients like phosphorus from entering waterways is critical in the MWRD’s goals to protect the quality of receiving waterways from potential algal blooms and hypoxia conditions. Densified activated sludge can also improve WRP performance and resiliency under changing flows and loads, while also increasing WRP capacity. Together these two focuses on resource management and ecosystem innovation cover the MWRD’s Strategic Plan goals of improving phosphorus removal and suspended solids capture through ecosystem innovation and by improving WRP operational efficiency and resiliency. 

The study also aligns with the MWRD’s Climate Action Plan goals in reducing greenhouse gas emissions, by experimenting with innovative ideas to enhance treatment performance. The anticipated outcomes may reveal more energy efficient treatment methods, such as a reduction in aeration. Furthermore, the project aligns with the Climate Action Plan's goals, centered on renewable energy measures, by exploring increased energy production through redirecting more organic carbon to the anaerobic digestion process. 

Pilot reactor testing is scheduled to begin in the third quarter of 2024 with a final report anticipated by winter 2026.