Solid Waste & PFAS


Town of Nantucket’s vendor Waste Options Nantucket (WON) under a co-permit with Town is performing sampling and testing of Nantucket Natural Compost (co-compost) product for PFAS compounds.  Testing is performed using appropriate protocol and a laboratory approved by Massachusetts Department of Environmental Protection (Mass DEP), in compliance with the Approval of Suitability (AOS) permit. 

Nantucket Natural Compost (co-compost) comes from organic Municipal Solid Waste (compostable waste) from the residents and businesses of Nantucket. The co-compost also includes dewatered sludge, which is an output from the Waste Water Treatment Facilities (WWTFs) that serve Nantucket.  The Municipal Solid Waste combined with dewatered sludge is processed through our large industrial drum and then screened and further processed through the compost facility. The product is then mixed with leaf/yard waste and windrowed outside for six months to finish.  WON is sampling the Nantucket Natural Compost (co-compost) as required by the AOS permit. PFAS sampling every three months was recently added to the AOS permit requirements. Sample collection and laboratory analysis is performed to meet MassDEP general PFAS sampling and laboratory guidelines. MassDEP and U.S. Environmental Protection Agency do not currently have PFAS standards for dewatered sludge, biosolids (treated sludge) or co-compost.

On January 27, 2021, the WON collected three different sample media (types) for PFAS testing: Nantucket Natural Compost (co-compost), reclaimed soils, and dewatered sludge from the WWTF. Nantucket Natural Compost (co-compost) sampling was completed in line with the MassDEP AOS permit.  The January 2021 testing reports and an updated Fact Sheet can be found here

On October 28, 2020, WON began quarterly PFAS sampling of the Nantucket Natural Compost (co-compost) product using an appropriate protocol and a laboratory approved by MassDEP, and in compliance with the AOS permit.  The October 2020 testing report including a Fact Sheet can be found here.

The Nantucket landfill and WON’s operations use materials delivered from the public and commercial vendors to use as ingredients to produce several products for potential re-use.  These may include:

  1. Co-Compost Facility Compost (also known as Nantucket Natural Compost) is a blend of dewatered sludge from the Waste Water Treatment Facility (WWTF), Compostable Waste (Municipal Solid Waste-MSW), and leaf/yard waste. The Co-Compost, defined here, is the material regulated under the MassDEP AOS permit.  The co-compost product has not been available to the public since August 2019. 
  2. Leaf/Yard Waste Compost, combination of grass clippings, leaves, very small branches and twigs and plant material (with no soil).  This material is stockpiled, screened and placed into windrows.  The material is then screed again and windrowed before distribution.  The majority of leaf/yard waste is delivered to the Landfill Facility by landscapers with some directly from homeowners in smaller quantities.  The vast majority of this material are from maintenance of homeowner gardens, lawns, etc.
  3. Mulch, a blend of branches, stumps and other wood material from trees, pallets, and other clean wood waste, and large plants.  This material is stockpiled in raw form until it is chipped with a grinder.  Once chipped, the material is screened to remove the fines.  Some of this material will be screened a second time to make a double ground mulch.  The rest remains in a single ground mulch.  Both are placed into windrows before distribution. The majority of this material is delivered by landscapers and commercial haulers from homeowners or sites on the Island being developed.
  4. Mixed Excavation Material, the majority of this material is from homeowner properties and consists of natural soils found on the Island that also contains clay, large inert materials such as stones, bricks, large branches, etc.  This material is primarily used as a bulking agent to make topsoil or other soil blends.  The material is screened before being used as a bulking agent.  At times, a high-grade sand can be extracted by screening the material depending on where on the Island it originated.  Most of this material is delivered from commercial haulers from new construction sites or existing structures.
  5. Topsoil, a blend of leaf/yard (compost) mixed with screened mixed excavation material or high-grade sand (special orders) at 2:1 to 3:1 ratio of mixed excavation material to leaf/yard.
  6. Sand, a product occasionally produced depending on what gets delivered for Mixed Excavation Waste. 

WON uses no PFAS chemicals at the Landfill or Compost Facility.  Any PFAS detected in the co-compost product likely originates from imported products (from the mainland or foreign countries) that are used commercially or in consumer products by households and enter waste streams from residential septic systems, product usage that end up in the trash, laundry, cleaning products, etc., to the WWTF and the Landfill.

On May 13, 2021, WON collected a third quarterly sampling of the finished Nantucket Natural Compost (co-compost) product for PFAS testing.  The May 2021 testing report with an updated Fact Sheet can be found here.

A June 2021 Fact Sheet and preliminary comparison of PFAS levels in Nantucket Co-Compost with other types of compost reported in a 2020 Report by Lazcano,, is available here.

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