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Determination of microplastics counts in leachate from US landfills

Investigator:  Olya Keen, UNC Charlotte 
Start Date:  June, 2024
Award Amount:  $112,013

Proposal Justification & Objectives

As microplastics (MPs) become a regulatory concern in surface water resources (Section 116376 of CA HSC), it can be anticipated that MPs would soon become a concern for POTWs discharging into surface waters.  At that point POTWs may look for sources of MPs in the influent, and landfill leachate is likely to come under scrutiny.

There is a fairly good understanding of MPs counts in raw wastewater and the ability of wastewater treatment plants to remove them, including the ongoing work by the PI’s team.  However, the main sources of MPs in raw wastewater are not well understood.  It would be reasonable to assume that landfill leachate may contribute to it, but it is not known if it is a major source or a minor contributor compared to domestic wastewater that is known to contain high MPs counts.  To date, the studies that measured MPs counts in landfill leachate were done mainly in China, with none in the US.  The typical composition of solid waste and management practices may be sufficiently different to produce very different results in different geographic regions.  

The goal of this project is to determine a typical range of MPs counts in the leachate from the US landfills.  The goal will be accomplished through the following tasks:

  1. Modify the ASTM method D8333-20 for analysis of MPs in landfill leachate
  2. Measure MPs in raw leachate from at least 10 landfills
  3. Measure MPs in digestate from 9 to 10 anaerobic digestors processing organic waste

This information can be used by landfill managing entities in anticipation of the MPs in leachate being scrutinized in the future.  If typical MP concentration is on par or less than that of domestic wastewater influents, it would provide the necessary information to avoid leachate rejection by POTWs on the basis of MPs in the future.