- Jeffrey Energy Center Constructed Wetland
Like other energy companies with coal-fired power plants in their portfolios, Westar Energy is upgrading its environmental systems to comply with more stringent federal and state regulations.
As the largest energy provider in Kansas, Westar was especially interested in finding better ways to treat the wastewater generated by the flue gas desulfurization (FGD) process at its Jeffrey Energy Center. At 1,857 megawatts, the center is the state’s largest power plant and could set a standard for other plants to follow.
With that in mind, Westar retained our team to develop a pilot project exploring whether more natural, environmentally friendly systems could be used to treat plant effluent. On a 2-acre site, we designed a constructed wetland engineered for metal removal, where approximately 7 percent of the plant’s FGD wastewater stream could be treated.
After identifying specific pollutants in the effluent and working with researchers from Kansas State University to identify soils and plants that could help filter them out, our team developed an environmental system that mimicked the biological processes that occur in a natural wetland. After two years in operation, Westar determined that the pilot project had effectively treated 19 of the 20 pollutants. The 20th, sulfate, would need to be removed separately through a targeted precipitation process.
Based on the pilot project’s success, Westar moved forward with construction of a full-scale constructed wetland to treat all of the plant’s FGD wastewater.
After a physical and chemical treatment process and sulfate-removal process, the FGD wastewater is discharged into a 28-acre constructed wetland for treatment. The project’s approach incorporates a combination of soils and plants that thrive in wetland to create a two-tiered filtration system. First, water moves vertically through a lower tier of saturated soil before then moving horizontally through gravel in an upper-tier wetland. The vertical flow helps to reduce environmental risks by filtering and removing metals through the saturated soils and microbes before water is exposed to the upper wetland soil, plant roots, invertebrates, birds and other wildlife. Water released from the wetland is then returned to the plant for reuse.
The constructed wetland now treats up to 230,000 gallons of FGD wastewater from the Jeffrey Energy Center daily. At the time of construction, it was the first constructed wetland treatment system in the world to treat wet flue gas on a commercial scale successfully. The project — which provides a natural, sustainable and energy-saving approach to wastewater treatment — received both state and national Engineering Excellence Awards in 2015 from the American Council of Engineering Companies, as well as the first-ever Water Award from Power magazine. The project also received the 2014 Edison Award from the Edison Electric Institute.
- Antidegradation analysis
- Construction administration assistance
- Construction quality assurance
- Engineering design
- Fatal flaw analysis
- Full-scale startup
- Pilot data analysis
- Pilot design and startup
- Plant water balance
- Technology development
- 28 acres of constructed wetland
- 160 gallons per minute of treatment capacity
- $40 million expected capital and operational savings over 15 years