Comparison of vertical-flow constructed wetlands for the treatment of wastewater containing lead and copper

This paper describes an investigation into the treatment efficiency and capital cost of vertical-flow constructed-wetland filters containing different plant communities and granular media with different adsorption capacities. The media included gravel, sand, granular-activated carbon, charcoal and filtralite (light expanded clay). Lead and copper sulphate were added to a polluted urban beck inflow water to simulate pretreated minewater or highway runoff. The interactions between growth media, microbial and plant composition and the reduction of lead, copper and BOD were investigated. For filters containing traditional media, a breakthrough of copper was recorded during the first nine weeks. After maturation of the biofilm, the wetlands performed well.