Water Treatment Plan, Keene, NH

Flow: 700-1200 gpm
Presure: ~75 PSI
kW: 62
Intertie: Net-Metered
Raw Water
Startup: 2012
Multi-Turbine/Net Zero Energy

The City of Keene, New Hampshire’s water treatment facility (WTF) system consists of a 3MGD gravity-fed system inclusive of a strainer and a pressure reduction valves (PRV); a large main PRV and a smaller bypass PRV. The City’s WTF treated raw water, having passed through the PRV, enters a flow control valve that manages flow through any combination of three filter trains. The PRV reduces pressure from the gravity-fed line descending from the raw water storage reservoir several miles away. Heat energy was released into the environment as side effect of reducing pressure in the supply system. The City of Keene was determined to recover this source of energy. The City wished to maintain the existing system’s functionality as well as have the option to utilize the generated power behind the meter or sell excess to the local grid.

In April 2011, Rentricity installed two new F2W turbine generators in parallel to the existing PRVs inside the City’s WTF. The two systems are used in tandem, at separate times, or shut off altogether. The energy recovery systems do not adversely affect the normal operations of the treatment facility. The recovery system adds value in the form of clean, reliable electricity from the inflow of water. The City of Keene’s WTF is fully powered by the electricity generated from Rentricity’s twin turbine generator system. It is also equipped to export excess power to Public Service of New Hampshire’s grid. This is the first WTF of its kind in the world and sets a new standard for a smart and sustainable water infrastructure.