Objectives :

  1. Conduct sampling of biosolids after dewatering and drying processes at two Miami-Date wastewater treatment plants.
  2. Analyze biosolids samples for PFAS content and component profile; determine the prevalent PFAS compounds.
  3. Conduct leaching experiments to evaluate the release of PFAS from biosolids under site-specific conditions.
  4. Estimate time dependent solubilization and the release characteristics of the PFAS homologues from biosolids.
  5. Further scientific understanding of PFAS originating from biosolids as a source in the environment, potential exposure pathways for human health and ecological effects.
  6. Provide recommendations for appropriate testing and land application practices of biosolids in Florida.

Expected Technical Results :

Practices for biosolids are being promoted at national and international scales with increasing interest and urgency for sustainable practices. However, the use of biosolids as soil amendments either by direct application or mixed with other organic materials (e.g., wood chips) to make compost provides an opportunity to effectively recycle these waste materials where their properties can be advantageous. However, there is an increasing concern about the levels of PFAS in the environment and its transport and accumulation. This research will provide an in-depth evaluation of the levels of PFAS in biosolids and their transport mechanisms. 

Research activities will focus on addressing the following questions:

  • What types of PFAS enter wastewater treatment plants partition to biosolids?
  • Should we be concerned about PFAS in biosolids for land application?
  • Do PFAS leach from biosolids over time? Is any difference in the PFAS chemical composition in samples collected before and after dewatering, after drying, composted biosolids and leachate?
  • Is there any effect on the PFAS dissolution behavior from biosolids in the presence of divalent metals like Ca2+ or Mg2+ that is potentially important to include in a fate and transport site evaluation?
  • What is the current status of PFAS regulations in the US?
  • Which PFAS should be included in a database for biosolids that would affect biosolids management.