Landfill Composter Shutdown Since February, Forcing Town To Stockpile Solid Waste

One of the town's critical pieces of infrastructure at the Madaket landfill - the massive, 180-foot composter - has been shut down since February after a series of problems were discovered, including a crack extending roughly 40 percent of the way around its circumference.

The composter, which processes Nantucket's household trash and organics, has been in operation since 1999 and is also referred to as a digester.

During the shutdown, the town's landfill operator, Waste Options Nantucket, has been trucking municipal solid waste, or MSW, several hundred yards away from the composting facility to be stored on top of an inactive lined landfill cell. Waste Options plans to "exhume" the solid waste at a later date and process it in the composter once it is operational, but that likely won't happen until late fall when the volume of incoming trash is reduced.

The structural crack in the composter's shell was first observed in November 2024, but the machine remained operational until February 2025. At that point, it was shut down, and Waste Options opted to install a collar around the compromised section of the shell, rather than cut out the damaged area and install a new shell section. That work was completed, but when the composter was restarted, an inspection revealed additional problems, including several internal sections that required new wear bars, which allow raw compost to rest between them and form a barrier that prevents MSW and biosolids from contacting the shell.

"It may have been possible to address only the worst sections and get through the summer, but that would have created more work during the slower season and introduced a risk of additional damage, potentially to the shell," Waste Options stated in a response to the Current. "Of the 180-foot length of the digester, approximately 120 feet of wear bars were installed around the entire circumference."

That work is now complete, but yet another issue cropped up: the composter's variable-frequency drive, which is for the operation of the machine's motor and gearbox, had sustained damage and needs to be replaced. A new drive has been ordered and is expected to be installed in the coming weeks.

Despite the four-month shutdown, the town stated in a response to the Current's inquiry that it had not affected capacity or the timeline and need for new lined cells.

"The stockpiling of the MSW on top of the inactive lined cell is a temporary measure," the town stated. "It is not affecting the landfill capacity. MassDEP is presently processing an application submitted by the town of Nantucket and Waste Options to construct a new lined cell, 3B. Once constructed, Cell 3B will not be used until the active cell, 3A, has reached capacity."

The problems with the composter cropped up just as the town was negotiating a new contract with Waste Options to run the landfill, and completing a deal to acquire both the composting facility and the construction and demolition building from Waste Options.

Just last month, on May 6th, 2025, the town entered into an asset purchase and sale agreement with Waste Options to buy the composting facility, for $1 million; and the C&D transfer station for $3.4 million. The Town and Waste Options also entered into a "Repairs Letter Agreement" to address the performance of certain repairs and improvements. The purchase is scheduled to close in November 2025.

"Upon transfer of ownership, the town will receive a fully refurbished digester shell that would cost more than $5 million if purchased new today," the town stated. "All recent work, valued at $400,000, was completed at no cost to the town. Considering that the town is buying the compost facility for $1 million, including this refurbishment performed by experienced contractors and overseen by Waste Options, which has over 25 years of experience with these matters, the town is pleased with this outcome."