Evidencing that improvements to wastewater treatment and use of fate models protect sources of drinking water

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My research program aims at protecting our water resources by improving wastewater treatment technologies, assessing the effect of CECs and assessing exposure to CECs. Work supported by my on-going Discovery Grant has provided ample evidence that contaminants of emerging concern (CECs) are present in wastewater discharges, a significant point source of contamination of surface waters. Our work has also demonstrated that advanced treatment technologies can significantly reduce the concentrations of CECs in treated effluents. In alignment with my research program, the specific objective of the research proposed for support by the NSERC Discovery Grants program is to provide evidence that by adding treatment steps, such as conventional or novel ozonation technologies, to the wastewater treatment train and using models to determine fate of CECs in receiving streams can protect the quality of sources of drinking water. This objective will be addressed by quantifying the additional removals of CECs and bioactive compounds provided by using advanced technologies, and then modeling the fate and transport of these CECs in receiving streams up to the point of intake into drinking water treatment plants. Predictions of the transport and fate of CECs in receiving waters will be made using existing modeling tools, such as the PhATE model. To calibrate these models, we will apply electro-conductivity measurements made in situ in rivers, a method that we have recently applied to improve sampling strategies and calculation of CEC removals. The model will be validated with field data and will be applied to a list of indicators compounds that we have developed over the last five years, that includes contaminants from various classes and showing variations in removals by microbial, oxidative and photolytic processes, as well as by partitioning. However, given the wide variety of CECs present in wastewater along with their transformation products, optimizing technologies or regulating discharges based on monitoring for specific chemicals may not be optimal. Bioanalytical methods, such as in vitro bioassays, will be used as a complement to chemical analysis to monitor the removal of known and unknown bioactive substances and evaluate the contribution of the effluent to biological activity in receiving streams. A better understanding of the potential for contamination of drinking water sources will help regulatory agencies assess the risks associated with the presence of CECs in wastewater effluent and to put in place appropriate guidelines and regulations. These studies will also demonstrate that investment in advanced treatment technologies can have a direct benefit in terms of protecting downstream sources of drinking water. Combining analytical, bioanalytical and modeling approaches will provide a tool for water resource management and protection of sources of drinking water.