OCWA partnering with the Township of Emo on water system upgrades

June 2, 2021

Historically, the treated water at the Emo Water Treatment Plant (WTP) has had elevated levels of THMs (trihalomethanes). Experience shows that plants with THM challenges may also have high levels of HAAs (haloacetic acids). Known as disinfection by-products (DBPs), these are chemicals that can be formed when chlorine is used for disinfecting drinking water.

In 2018, the Township of Emo contracted operations and maintenance of their water and wastewater systems to OCWA. Soon after, the Agency’s Process Optimization and Technical Services Group conducted a comprehensive evaluation of various technologies that could be employed to reduce THMs and HAAs levels in the water distribution system.  

Ensuring water remains safe 

The Ontario Drinking Water Quality Standards specifies the maximum acceptable concentration for THMs and HAAs. 

“They [THMs and HAAs] were creeping up to the point where some of the testing was over that limit,” OCWA northwest regional manager Jeff St. Pierre explained during an online project funding announcement. “This is what prompted us to look at different upgrades that we could apply. At the end of the day, it’s about ensuring that the water remains safe and potable for consumers.”

To support the evaluation, local OCWA operations staff completed a DBP Sampling Program to fully understand the factors causing and affecting the formation of THMs and HAAs at the treatment plant. 

The sampling program found that high total organic carbon (TOC) in the source water (Rainy River), the dosing of chlorine for disinfection and long water retention time in some zones of the distribution system were the main factors. Using this information, OCWA’s Process Optimization and Technical Services Group explored different solutions and worked with the Township to choose an approach that best suited its needs. 

OCWA assisted with funding application

OCWA and the Township worked together to apply for government funding for the necessary upgrades to reduce the levels of THMs and HAAs in the water distribution system. In February 2021, it was announced that the project was a successful recipient of joint federal-provincial funding through the Green Infrastructure Stream of the Investing in Canada Plan. Under this arrangement, the Township will also contribute to the project.

The project includes upgrading Emo’s WTP by flushing existing raw water intake piping to remove excess sand buildup, installing an intake screen to prevent future blockages, and upgrading the chemical feed systems with automatic conversion to back up pumps in the event of failure. It also introduces an anion exchange treatment solution (similar to the one pictured above, in use at the Rainy River WTP), which removes organic matter from the water and reduces THMs and HAAs formation. 

Work on the project is expected to begin in June 2021 and be completed by December 2022.

OCWA is committed to ensuring safe, potable drinking water for its clients. We can work with your community to find tailored solutions for your drinking water system needs and help with funding applications. Please reach out to your local OCWA representative