Lance Lin: Cleaning dirt with dirt

Lian-Shin "Lance" Lin, professor and chair of the Wadsworth Department of Civil and Environmental Engineering

Two wrongs aren’t supposed to make a right, but Lian-Shin "Lance" Lin, professor and chair of the Wadsworth Department of Civil and Environmental Engineering in the Statler College of Engineering and Mineral Resources, has discovered how combining two kinds of contaminated water can yield pure, clean water.

Story by Micaela Morrisette, Research Writer, WVU Research Communications
Photo by Paige Nesbit, Director of Marketing

Benjamin M. Statler College of Engineering and Mineral Resources

In 2019, a team led by Lin received $400,000 from the Department of Energy to use two different wastewaters – “cooling blowdown water” produced by thermoelectric power plants and “produced water” from shale gas wells – to clean each other, a process that also yielded valuable byproducts like chlorine.

Now, in a new stage of the research, Lin is working with industry partner Leidos to explore what happens when he co-treats produced water not with blowdown water, but with “flue gas desulfurization effluent,” or FGD effluent, another liquid waste product from thermoelectric plants. 

Q: What exactly is flue gas desulfurization? Why is the liquid waste produced by FGD a problem?

A: The gases from the exhaust flues of coal-fired power plants contain sulfur dioxide. If that sulfur dioxide reaches the atmosphere, it causes acid rain, so it needs to be removed. To “desulfurize” the flue gas, plants use chemicals and water in a process that removes sulfur dioxide but also generates a wastewater effluent containing toxic chemicals from the coal. It’s that FGD effluent that our lab is treating by mixing it with produced water, which is wastewater that emerges from gas wells along with the shale gas.

Q: This research sounds suspiciously like magic. How are you able to purify water just by mixing two dirty, toxic batches of water together?

A: Mixing two wastewaters with complementary chemistries can cause liquid pollutants to form solids. Subsequently, through settling, those solids simply fall out of the water.

In our current research, where we’re mixing the FGD effluent with produced water from the gas wells, one of the solids that forms is barite. That’s a critical and valuable mineral, commonly used as a weighting agent for drilling wells.

Q: So, not only can two contaminants be used to clean each other, but in the process you turn pollutants into useful products like barium.

A: Our process yields both barium and calcium carbonate solids, as well as low-salinity water and 10-pound brine – all four of which are used by the same industries that were the source of the wastewaters in the first place. Ten-pound brine can be useful for drilling operations, while power plants use calcium carbonate in the FGD process and low-salinity water for cooling operations.

This kind of “circular economy” for waste management is still an emerging approach for utilizing resources more efficiently, and I haven’t yet seen full-scale applications in the power industry. Currently, Environmental Protection Agency regulations set limits on several pollutants for discharge and require coal-fired power plants to install and run treatment processes for FGD effluents, but the EPA’s recommended treatment process doesn’t recover any useful chemical products and the effluents are commonly disposed of in impoundments. The co-treatment process we’ve developed, on the other hand, offers resource recovery and chemical savings. 

Q: You believe this technology is capable of getting us to “zero liquid discharge” from power plants. Does that mean that the only water to escape a thermoelectric plant using your technology to treat its wastewater would be in the form of steam? 

A: Yes, evaporation of steam from cooling tower operations is inevitable, but by maximizing water recovery through our treatment processes, we can reduce environmental impacts from discharge of the effluents and we can reduce demand for freshwater resources.

Lowering the amount of freshwater needed for power and energy production is a big benefit. In north-central Appalachia, nothing uses more water than power generation. Reducing power plants’ water use would mean more freshwater is available for competing uses, like drinking water systems.

Q: When you started looking at using wastewater streams to co-treat each other back in 2019, you were using the produced water from gas wells to treat power plants’ “cooling blowdown water,” not their FGD effluent. Does your treatment process have the potential to work with multiple kinds of wastewater?

A: It does, and I have also applied the approach to managing acid mine drainage and municipal wastewater. For that, iron and aluminum, the two prevalent chemical elements in acid mine drainage, are extracted. Those elements can then be used in treatment of sewage and other municipal wastewaters to improve energy efficiency and recover nutrients.

Q: What stage has this research gotten to, and what’s your end game?

A: In June, we conducted several test runs of our technology, using FGD effluent from Longview Power Plant near Maidsville, West Virginia, along with produced water from a shale gas operation at the Morgantown Industrial Park. Now we’ve completed testing of the co-treatment process for FGD and produced water, so we’re resuming work on the co-treatment process for blowdown water and produced water that we started in 2019. In addition to undergraduate research assistants Cole Hodges and Morgan Amos, who have been a great help in building the pilot process and running the tests, our team includes PhD students Mohammad Ahmed and Payton Seats, postdoctoral researcher Karen Buzby, and Harry Finklea, an emeritus professor in chemistry. Doctoral student Chris Anderson also volunteered his time to help run tests.

West Virginia University is located in one of the largest energy-producing regions of the U.S., and this project was motivated by industrial needs and our land-grant mission. The goal has always been to demonstrate feasibility of the treatment concept at pilot-scale operation and to generate results that would allow design of full-scale applications. We have now successfully demonstrated feasibility and we have generated valuable by-products using real, field-collected waters. Our preliminary results show that the by-products are of high quality for their intended uses, so the next step is to present the results to industry partners Longview Power and Northeast Natural Energy, with a view toward potential real-world development. 

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