From the website:
The Keene Wastewater Treatment Plant (WWTP) is owned by the City of Keene and is operated by the City's Department of Public Works. It is a Grade IV secondary treatment, activated sludge facility. Located on Airport Road, behind the Dillant-Hopkins Airport, the (WWTP) presently treats the domestic and industrial wastes from the communities of Keene, Marlborough, and some sections of Swanzey with a combined population of 35,000. It also accepts septage waste from the local area.