Gray water line will help power plant grow greener
A first-of-its-kind “gray water” pipeline for the Medical School is now being installed to reduce the amount of fresh water the campus power plant uses while generating steam, electricity and chilled water.
The gray water line has been designed into the Albert Sherman Center (ASC), a nine-story, 500,000 square-foot research and education complex now under construction on the northwest corner of the Worcester campus. It’s one of several sustainable elements designed into the ASC, to align with the LEED (leadership in energy and environmental design) standards established by the U.S. Green Building Council.
“Gray water is not fresh water, but it’s not sewerage or contaminated water either. It’s relatively clean water, that with minimal treatment, can be used in various ways,” said Shawn McGuinness, AIA, LEED AP, the Medical School’s senior architect and project manager overseeing the ASC design.
Approximately half of the campus water demand is for so-called “make-up water” which is drawn from the city of Worcester’s municipal system to replace water that evaporates from the power plant’s cooling towers. This evaporation is often seen as mist rising from the towers which are located on the western wall of the plant.
The 12-inch gray water pipeline will connect the power plant to a drainage system within the ASC that will capture rainwater from the building’s roof and water that condenses around the building’s air conditioning systems. In an average year, approximately 250,000 gallons of rainwater and between 300,000 and 500,000 gallons of condensate water will flow through the gray water line and be used at the power plant, thereby reducing the amount of municipal water needed.
“We are growing as an institution, adding educational, research, and clinical space, so we are trying to manage that growth to reduce the school’s environmental impact,” said Melissa Lucas, UMMS sustainability and energy efficiency manager. “Capturing and using this gray water makes more sense than just letting it drain away.”
Workers began excavating the trench for the gray water line on June 14 and are expected to finish the project in August.
Also related to the ASC, the school is in the midst of a 14,000 square feet expansion of the power plant complex to accommodate a new 7.5 megawatt, gas-fired, combustion turbine and associated equipment that will boost the plant’s capacity in ways that actually lower the plant’s carbon footprint. When the new gas turbine is operating, one of the plant’s 35-year-old gas and oil-fired boilers will be taken off-line and kept in reserve as an emergency back-up. Since natural gas burns cleaner than oil, and the new jet turbine is highly efficient, the expanded power plant will actually have lower greenhouse gas emissions, despite its added generating capacity.