Quantification of PFAS in Source Separated Organic Processing

Investigators: Wayne Parker & Anh Pham,  University of Waterloo, Waterloo, Ontario, Canada 

Start Date: 2024

Award Amount: $192,000  

Project Duration: 2 years 

Proposal Justification & Objectives 

Processing source separated organics (SSO) through composting or anaerobic digestion (AD) is increasingly being employed to create value-added products and to increase the circularity of organics throughout the economy. Because the presence of PFAS in composts and digestates may impact the ability to beneficially use these materials, quantifying PFAS in SSO and understanding their fate through composting and AD can provide information regarding how to reduce PFAS levels through improved processing (e.g., enhanced screening) of the final product. However, there is a lack of validated methods for obtaining accurate measurements of PFAS in raw and processed SSO, as well as in associated packing-related contamination. Further, the fate of PFAS associated with SSO and packaging-related contaminants through composting and AD facilities has not been investigated. Hence, it is not clear whether existing levels of PFAS in SSO products are at a problematic level and options for reducing them, if necessary, have not been identified.

Given these knowledge gaps, the primary objectives of the proposed research are: 

• To develop robust procedures for sample collection, pre-processing and analysis for the quantification of discrete PFAS and total organic fluorine (TOF) in SSO and associated contaminants (e.g., packaging), final compost, and digestate
• To compare the levels of PFAS and TOF concentrations between SSOs received atdifferent processing facilities
• To quantify the fate of PFAS and TOF in full-scale SSO processing facilities and assessthe role of contamination from packaging materials on PFAS and TOF fate

Description of the Research Approach & Experimental Design 

The proposed project will initially develop and validate methods for sampling and pre-processing of SSO, packaging-related contaminants and SSO products (i.e., composts and digestates) that are able to generate representative matrices suitable for subsequent analysis of PFAS and TOF. Analytical methods for PFAS (by LC-MS/MS) and TOF (by Combustion Ion Chromatography) will then be developed and validated for the various sample types. Finally, using the validated methods, inter-stage field sampling campaigns will be conducted at major full-scale composting and AD facilities. The data generated will be employed to compare PFAS and TOF levels between raw and processed SSO at the different facilities to establish a baseline for the industry. Further, mass balance models will be developed to establish the fate of PFAS and TOF through the facilities and support the identification of practices that could reduce PFAS presence.