Researchers at West Virginia University are looking at how water produced from oil and gas operations can help clean water used to cool thermal electric power plants.

Power plants across the country use more than four times as much water as all U.S. homes and account for 41% of total water withdrawals, according to federal data.

Now, with the aid of a $400,000 Department of Energy grant, West Virginia University researchers aim to maximize water reuse and reduce chemical and energy footprints resulting from thermoelectric generation.

Lance Lin, civil and environmental engineering professor, is the lead investigator of a research project aiming to reduce the use of fresh water resources by the nation's power plants. Credit: Paige Nesbit, WVUAt those types of power plants, water is used to cool down high-temperature steam from turbines in a heat exchanger. The warm water is circulated to cooling towers to eject the heat into the atmosphere. As the water reaches the cooling tower, some of it evaporates, creating white plumes that pour out of the towers. A portion of the water is retained and recirculated through the system.

As water is lost, natural salts in the water reach concentrations that could foul the cooling system. As a result, plant engineers purge this "blowdown water," which often contains chemicals such as calcium and magnesium. If left alone, these chemicals can form scale on heat exchanger surfaces, affecting the equipment's effectiveness.

But blowdown water needs to be treated before it can be released back into the environment or reused, a costly process in terms of chemical and energy requirements.

The university researchers are testing a process that would combine blowdown water with so-called “produced water” that comes from oil and gas wells in places such as the Marcellus formation in parts of West Virginia.

By adding produced water to blowdown water, the result is water that is clean enough to reuse, the researchers said. Elements in blowdown water closely match what industry uses to remove scaling elements in produced water. The scheme could make treatment or reuse of produced water less expensive because plant personnel would use a waste product instead of commercial chemicals.

The proposed treatment process consists of softening, organics and suspended solids removal, reverse osmosis, brine electrolysis and thermal desalination. The treatment process also may help produce two other products, chlorine and 10-pound brine. The chlorine would act as a disinfectant on the recirculating water and control bacterial growth in the recirculation system. And the 10-pound brine, meanwhile, would have industrial applications including water softening and oilfield fluids.

The research team will collect water from the $2 billion, 700 megawatt Longview Power Plant near Maidsville, West Virginia, and use produced water from a shale gas operation at the Morgantown Industrial Park near the university.