Project Summary:  

Effluent from municipal wastewater treatment plants is typically treated to reduce microbes by chlorination or other disinfection methods, not to remove chemical pollutants. Thus, wastewater effluent is a major source of contaminants of emerging concern (CEC) like pharmaceutical and personal care products into Puget Sound and other receiving waters. These contaminants pose a risk to aquatic life, including endangered Chinook salmon (Oncorhynchus tshawytscha). 

Dr. Terry Collins of Carnegie Mellon University developed a bio-inspired catalyst that uses hydrogen peroxide to rapidly oxidize contaminants in wastewater using tetra-amido macrocyclic ligand complexes (TAML). Before this technology can be adopted to improve wastewater treatment in Washington State, research is needed to optimize treatment conditions and demonstrate improvements in health for aquatic animals exposed to effluent.

Study Objectives:

1) Demonstrate TAML treatment reduction of CECs in effluent from a representative municipal facility discharging to Puget Sound, and

2) Show improved outcomes for aquatic animals exposed to TAML-treated effluent. 

These objectives will be accomplished by collecting effluent from a King County Wastewater Treatment Plant, treating it with TAML, using high-resolution mass spectrometry to measure concentrations of select CECs and trends of non-target chemicals, and toxicological testing using zebrafish and juvenile Chinook salmon. 

Scope:  

Researchers will work with King County’s South Treatment Plant to test the addition of TAML/H2O2 treatment. Effluent released from this location is regulated under a National Pollutant Discharge Elimination System permit. Treatment includes primary and secondary treatment, followed by disinfection with chlorine.  

1. Batch testing with zebrafish to refine treatment parameters  
   • Researchers will vary the concentration of catalyst, the concentration of hydrogen peroxide, and the contact time with effluent to select a combination that will optimize removal of CECs while improving health outcomes for aquatic animals. Zebrafish (Danio rerio) will be used to screen the effluents generated in the batch tests.
2. Juvenile Chinook exposure study to determine benefits to target organisms
   • To ensure safety and benefits of TAML treatment to target organisms of concern to Washington State, researchers will conduct a sub-chronic exposure study with juvenile Chinook salmon. Results of this study will be compared with our 2021 study evaluating impacts to juvenile Chinook from exposure to wastewater effluent from this same source.

Research partners: 

Dr. Terry Collins & Xiawei Ma, Carnegie Mellon University 

Dr. Andy James, University of Washington Tacoma – Center for Urban Waters 

Dr. James Meador, MariTox Consulting  

King County Wastewater Treatment Division – South Treatment Plant 

Funders:

Washington Stormwater Strategic Initiative Lead (SIL) – funded by the US EPA National Estuary Program 

Related Links: 

• About TAML from SUDOC: https://sudoc.com/newtaml 
• Dr. Terry’s Carnegie Mellon Institute for Green Science: https://www.cmu.edu/igs/  
• King County South Treatment Plant treating process: https://kingcounty.gov/en/dept/dnrp/waste-services/wastewater-treatment/facilities/south/treatment-process