Gravity-fed water system saves Jersey City more than $375,000 per year

Iselin, N.J. — Construction was completed this month on an innovative gravity-fed water supply system that is estimated to save Jersey City $375,000 per year in electricity costs.

The Boonton Reservoir, 26 miles from Jersey City, supplies some of the highest-quality drinking water in the state. The Jersey City Municipal Utilities Authority (JCMUA) operates an 80 million gallon per day (MGD) water treatment plant that is supplied by the reservoir. Until recently, water was directed to a raw-water pump station below the reservoir, and then pumped back uphill into the settling basins of the treatment plant. To accomplish this, six 20 MGD pumps with 250-horsepower motors consume approximately $500,000 in electricity each year.

Based on historical records, Hatch Mott MacDonald determined that for eight or nine months of the year, the potential head in the reservoir allows water to be supplied by gravity alone, using an 84-inch-diameter bypass pipe. HMM calculated the average savings in electricity at $375,000 per year.

The return on investment is immediate, as the electrical savings offset the debt service on the 20-year project loan for 2,000 feet of 72-inch and 84-inch diameter pipeline, valving, and controls. Initial trials of the new system showed better than anticipated results, indicating an even greater potential for energy savings.

The project includes an upgraded 100 MGD rapid mix basin, and flow pacing of coagulant chemicals.  The project also features an upgrade to the Supervisory Control and Data Acquisition (SCADA) system using an Ethernet-based, fiber optic, and redundant network.

HMM and JCMUA are currently collaborating on a project to harness hydropower from the spillway of the reservoir's dam. Regulations enacted in July 2013 make this a financially attractive plan that will result in a "net zero" carbon footprint in the future for the facility.