Mid-Atlantic Region Reverse Osmosis Project in Philadelphia to Provide Significant Water Savings

As the federal government’s landlord, GSA works to use our influence to reduce the government’s environmental impact.  GSA developed the Green Proving Ground program, which aims to drive innovation in environmental performance in federal buildings and help lead market transformation through deployment of new technologies.  One such technology is the reverse osmosis project underway at the Veterans Affairs Regional Office and Insurance Center (VAROIC) in Philadelphia, PA.  

The VAROIC utilizes cooling towers for building and data center cooling, which are a significant source of water use in many federal facilities.  Cooling towers function to reject heat from a building by evaporating water, which cools the remaining water in the system.  As the initial volume of water evaporates, it leaves behind a cycle of concentrated solids.  Continuous operation of the cooling towers results in additional cycles of concentration being left behind.  These dissolved solids must be flushed out of the tower – a process called “blowdown” – to prevent damage to the equipment and degradation in cooling performance.  

A team of Mid-Atlantic PBS employees led a study to determine the effectiveness of the VAROIC’s cooling towers.  They found that the cooling towers were running at four cycles of concentration before the water was flushed out and replaced.  At four cycles of concentration, the VAROIC was blowing down more than 3 million gallons of water annually.

The team took this information as an opportunity to test the use of reverse osmosis (RO) to increase the cycles of concentration and decrease the amount of water used annually.  RO membranes were installed at the VAROIC and began operating in February 2012.  Water is forced through the semi permeable RO membranes, which catch and hold all of the solute, allowing the purified water to pass to the other side.  The purified water enters the cooling tower clean of solutes, which decreases the amount of build-up in the bottom of the tower as water is evaporated.  

Data shows that utilizing the RO process will produce significant water savings:

• By purifying the water before it enters the tower, the RO membranes decrease the water wasted during blowdown, increasing the cycles of concentration.  The VAROIC’s cooling towers, which were running at four cycles of concentration, will increase to the equivalent of nearly 100 cycles of concentration.
• With the RO system in place, less than 100,000 gallons of water will be used annually for blowdown - that means nearly 3 million gallons of water will be saved each year!
• The 3 million gallons of water saved at the VAROIC alone will meet the GSA Mid-Atlantic Region’s goal of a two percent water reduction, a goal developed in support of Executive Order 13514 Federal Leadership in Environmental, Energy and Economic Performance.

The reverse osmosis project at the VAROIC in Philadelphia is a significant example of GSA driving innovation in environmental performance in federal buildings.  The RO process in water treatment for government facilities is novel, but as more data is collected and the system’s benefits are demonstrated, it can be replicated in other federal facilities across the country.  

Please contact John Tegan at (215) 446-4809 or john.tegan@gsa.gov for more information on the RO project.

This article is part of the Summer 2012 issue of the FOCUS newsletter. Please visit the Focus Newsletter page to read our newsletter. To subscribe to FOCUS, complete the online subscription form.