City of Keene, NH
The City of Keene, New Hampshire’s water treatment facility (WTF) system consists of a gravity fed system inclusive of a strainer and a pressure reduction valve (PRV). In its original set-up, the City’s WTF treated raw water passing through three filter trains, each of which was controlled by PRVs. The valves reduced pressure from the gravity fed line descending from the raw water storage reservoir. Heat energy was released into the environment as side effect of the 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 turbine generators in parallel to the existing PRVs inside the City’s WTF. The two systems can either be 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 the local grid. This is the first WTF of its kind in the world and sets a new standard for a smart and sustainable water system.