Researchers hoping to reduce water use at power plants
Researchers at West Virginia University are testing an idea to help save freshwater resources by combining wastewater from power plants with wastewater from fracking.
the power industry is the biggest water user in West Virginia. Nationally, it is the second biggest, behind agriculture. And fracking produces a lot of wastewater, called produced water — maybe 500,000 to 1 million gallons per well.
Thermoelectric plants use water in heat exchangers. Over time some of the water evaporates and the natural salts in the water become concentrated to the point where they could foul the cooling system. That water is called blowdown water. It has to be treated before it can be further recirculated or returned to a river or lake.
Meanwhile, produced water from fracking contains other substances that could harm the cooling towers, like magnesium, calcium and strontium. But when the two wastewater streams are mixed together, the chemicals combine in a way to precipitate out of the water. This produces clean water to recirculate as well as two beneficial byproducts: chlorine to disinfect the cooling system and 10-pound brine that has several industrial applications.
"The beauty of this approach is you solve two problems with one integrated solution," said Lance Lin, a civil and environmental engineering professor and principal investigator on the project.
Lin said they are still in the early stages of the project. They've determined the mixing ratio to get the best results and now are looking at treatments that could further clean the wastewater.
The researchers obtaining fracking wastewater from WVU's Northeast Natural Energy research well at the Morgantown Industrial Park and blowdown water from the Longview Power plant.
Paul Ziemkiewicz, director of WVU's Water Research Institute, came up with the idea for the project. He said it might not be a system that will be practical everywhere, but it is in West Virginia, which has a high concentration of coal and gas fired power plants sitting atop the nation's biggest natural gas play.
"If you're going to start anywhere, this is the place to start," he said
The project is funded by a $400,000 Department of Energy grant.