The New Hanover County landfill in Wilmington, N.C., is the only one in the state with a wastewater treatment plant, and it requires high maintenance. Knowing landfills produce leachate for years after closure made officials think about ways to eliminate the treatment plant. They approached CDM, an engineering firm in Raleigh, N.C., along with North Carolina State University and the Water Environment Research Federation (WERF). CDM suggested a constructed wetland leachate treatment system.The university conducted a pilot project to see which type of wetland — free surface (water is visible) or subsurface — would work best with the leachate. The
