Populated with cattails and water lilies, frogs, fish, and the occasional muskrat, wetlands usually conjure images of a wildlife refuge. But an emerging technology, known as constructed wetland treatment systems, has proven these areas also have a functional place in the world of wastewater treatment.
Harnessing the inherent natural productivity of their ecosystems, constructed wetland treatment systems successfully treat a wide range of wastewaters, including acid mine drainage, domestic and industrial wastewaters, agricultural, storm water runoff, and landfill leachate.
Appealing because the installation, operational, and maintenance costs are typically lower than conventional treatment systems, constructed wetland systems require less energy and promote creation of wildlife habitats.
When the City of Lancaster was required by the Ohio Environmental Protection Agency (EPA) to reconstruct the Stonewall Cemetery Road Landfill cap following leachate outbreaks and contaminated groundwater, constructed wetlands proved to be an extremely successful solution.
Burgess & Niple (B&N) designed a series of seven wetland cells to treat the leachate-impacted groundwater at the 32-acre site, which was originally closed in the 1970s. Operational since 1999, the cells have had long-term metal and nitrogen removal success and the site meets all Ohio EPA requirements.
"The wetland treatment system designed by Burgess & Niple has proven to be a very cost-effective, environmentally sound solution for the City,” said Tim Morrow, City of Lancaster Environmental Specialist. “The natural process used to treat the waste stream is a perfect fit with the City's plans to become more environmentally friendly."
Because of their self-sustaining habitats, constructed wetland treatment systems also successfully handle fluctuating hydraulic and pollutant loads which, in more traditional treatment approaches, can cause operational problems.
This was the case at the United Methodist Church’s Camp Otterbein in Logan, Ohio. Loads to its 40-year-old treatment plant often increase overnight as groups arrive to use the campsite. To replace the camp’s existing plant, B&N recommended a new extended aeration system with flow equalization, aerated sludge holding, and a constructed wetland polishing cell.
The design not only solved the load issue, but also created something extra for the campsite – a new wildlife habitat. Located directly across from the site’s main entrance, the constructed wetland blends into the camp’s natural surroundings and over time, will establish a wildlife habitat to serve as an educational opportunity for visitors.
For additional information on constructed wetland treatment systems, please contact Mitchel Strain, CPSS, at firstname.lastname@example.org or Brian Tornes, PE, at email@example.com