A wastewater treatment plant under construction in Mamaroneck, N.Y., is the likely source of thousands of small quarter-sized disks that washed up on the Sound shore as far east as Mattituck in recent weeks.
The Westchester County Department of Environmental Facilities reported on March 8 that the disks escaped from one of six treatment plant aeration tanks undergoing upgrades. Department spokeswoman Caren Halbfinger confirmed on March 25 that the disks came from the Mamaroneck plant.
The disks, shaped like wagon wheels, came ashore at Bailie Beach in Mattituck last weekend. Westchester officials said they are made of high density polyethylene, a nontoxic plastic used for milk cartons and other everyday food storage containers. They are used to provide a growing surface for bacteria used in the sewage treatment process.
Dr. Cheryl Archbald, Westchester County’s acting commissioner of health, said the disks pose no public health risks and can be thrown into the garbage.
“As with any debris, it is recommended that people use gloves or wash their hands after handling the disks,” she said in a press release.
Westchester County workers picked up thousands of the disks from beaches between Rye and New Rochelle after the spill, and the disks have been spotted at several locations on Long Island’s Sound shore as well.
Ms. Halbfinger said the disks were chlorinated before being released, further diminishing any potential health threat. She said that after a heavy rain in early March, the tanks that contained the disks backed up into a tank under construction that did not yet have screens in place to keep the disks from washing out into the Sound.