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Earth Sustainability Month at NIEHS

By Laura Hall
June 2010

Water is falling down the cooling tower
Water is cooled as it falls down the cooling tower that serves as part of the chilled water system used to cool campus buildings. The off-site Keystone Building has its own heating and cooling systems. (Photo courtesy of Steve McCaw)

Cooling tower piping
Cooling tower piping and valves transfer water into the cooling towers for chilling. The system uses water for heat transfer, like the refrigerant in a residential air conditioning unit. (Photo courtesy of Steve McCaw)

A variable speed drive for water pump
A variable speed drive, shown above, slows down water pump motor speeds to match the pumping needs thereby reducing electrical demand and power costs. (Photo courtesy of Steve McCaw)

Reverse osmosis system
The anticipated completion and start-up time for the new reverse osmosis system, above, is July 2010. The white tubes hold the filtering media. (Photo courtesy of Steve McCaw)

Paul Johnson, right, and NIEHS staff on the waste handling facility
Paul Johnson, right, told NIEHS staff on the waste handling facility tour about how waste is collected, evaluated, packaged, and then stored before disposal. The waste management team also collects some of the waste laboratory solvents and sends them to outside companies for use as fuel, he said. (Photo courtesy of Steve McCaw)

Earth Sustainability Month activities during the second and third week in May gave NIEHS employees the opportunity to go behind the scenes to see firsthand how energy and water are being conserved and waste is being handled at the Institute. NIEHS offered tours of the central utility plant, solar photovoltaic array, waste handling facility, and incinerator facility.

Most of the time, these conservation measures and most of the waste handling activities normally go unnoticed. However, in late May, facilities staff members were gratified to learn that NIEHS had won the 2009 Department of Health and Human Services Organization Green Champion Award for its comprehensive sustainability program (see related story (

During the central utility plant tour, NIEHS Operations and Security Branch Chief Mitch Williams told visitors about the ways NIEHS reduced its overall electricity usage by 10.3 percent and water usage by 25 percent through conservation measures during the first half of fiscal year (FY) 2010 relative to FY 2009.

The Institute retrofitted campus lighting with more efficient fixtures, installed a 34.5-kilowatt DC photovoltaic solar array on the B module roof of the main building, and made energy efficient adjustments of the temperature settings for the chilled water that cools campus buildings. Over the course of a year, the solar array alone has generated enough energy to power five homes for one year.

NIEHS reduced water use through installation of low-flow toilet fixtures and waterless urinals and reduced demand for chilled water with lower temperature settings. In response to the severe drought of 2007, NIEHS installed faucet aerators, showerheads, and flush valves that reduced the water flow rates in the campus plumbing fixtures, cutting the total annual water use by approximately one-third.

In addition, a new reverse osmosis system for the central utility plant condenser water system is near completion. By filtering the water used in the NIEHS cooling system, the system reduces mineral deposits that cause scale buildup within the heat exchanger inside the plant chillers and make the equipment less efficient. Filtered water can circulate in the system for longer periods, reducing the need for 8.5 million gallons of city water and saving $65,000 annually.

Also underway is a piping construction project that will allow the central utility plant to operate the chillers that cool the NIEHS and the neighboring Environmental Protection Agency (EPA) buildings more efficiently. Piping changes to the chilled water system allows for diverting water to different chillers, so they can operate closer to full load, where they are the most efficient. 

NIEHS is currently investigating the possibility of using Durham County reclaimed or gray water in the condenser water system that is part of the campus cooling system, said Williams. If acceptable for the system, this gray water can replace the approximately 50 million gallons of potable city water used each year by the cooling towers serving the NIEHS and EPA campuses and save 40 percent of the current total NIEHS and EPA city water bill.

During the May 20 waste facility tour, Hazardous Waste Manager Paul Johnson explained how the waste management team safely handles, stores, and transports hazardous and non-hazardous waste at NIEHS. Johnson described the regulations and safety requirements that must be followed to ensure safe handling of the materials.

Environmental Compliance Officer Bill Steinmetz discussed how waste from NIEHS laboratories is incinerated and emissions are controlled using a wet scrubber. Biologist Cindy Innes, who went on both the waste facility and incinerator tours, said afterwards, "It was interesting to learn about how the operators work out the combination of different waste products, such as bedding and plastics, to keep the temperature of the incinerator in a precise range to maximize combustion efficiency and help control emissions." 

Many of the NIEHS efforts to promote sustainability are described in detail within the recently released NIEHS "Sustainability Report" (

(Laura Hall is a biologist in the NIEHS Laboratory of Toxicology and Pharmacology currently on detail as a writer for the Environmental Factor.)

Waste handling facility
"There are a lot of intricacies about storing waste that we don't think about from the lab, such as how they separate and store waste," said Innes. NIEHS waste materials are stored in different areas of the waste handling facility depending on their hazard characteristics. The door, above, leads to one such area. (Photo courtesy of Steve McCaw)

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