Investigation of the role of organic matter in partitioning of chemicals in the municipal wastewater treatment process

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The widespread uses and applications of historic and newly emerging chemicals of environmental concern (CECs) is of increasing interest to the scientific community, industry, government and the general public in response to the potential health risks of acute and chronic exposures of CECs to organisms in receiving environments. CECs are introduced into aquatic environments through various sources including wastewater streams, agricultural and storm-water runoffs. Of these, municipal wastewater treatment plant (MWTP) effluents are a continuing issue for Canadians making the improvement of municipal wastewater management a critical element for a sustainable ecological future for lakes and rivers.Partitioning of CECs to organic matter (OM), is important in their fate and transport during the MWTP process, but has been poorly investigated in MWTPs. Partitioning to OM has historically been described via chemical hydrophobicity which has been included in MWTP models via the octanol-water partitioning coefficient. However, CECs include contaminants having widely varying physicochemical properties which may not follow partitioning based on hydrophobicity. Knowledge of CEC partitioning behaviour is essential for determination of bioavailability and degradation, and potential MWTP loadings to the environment for the assessment of new and existing chemical impacts on human and environmental health.The goal of the proposed research program is to conduct comprehensive fundamental and applied research on the fate and transport of CECs including polybrominated diphenyl ethers (PBDEs), pharmaceuticals and personal care products (PPCPs), and nanomaterials (NMs) in MWTP processes. The program includes three projects with objectives of: (1) Assessment of MWTP models to determine necessary physicochemical parameters and partitioning mechanisms needed to be further understood to inform model improvement and development; (2) Determine the partitioning behaviour of PBDEs to various MWPT OM size fractions to elucidate partitioning mechanisms and correlate to various physicochemical parameters; and (3) Extend knowledge gained for PBDEs to research PPCPs and NMs including validation of passive organic chemical integrative samplers. Knowledge gained from this research program will be a critical component in our ability to assess and delineate the potential implications of CEC remediation, manufacture and disposal, while helping to open new approaches to MWTP processes to help mitigate CEC loading to receiving environments. The potential users of the results included water and wastewater treatment utilities, environmental protection agencies, industry, and governmental decision makers. The model improvements may also be adapted for use in MWTPs, in Canada and worldwide, to help inform relevant decisions on updating of treatment processes to safeguard environmental health.