Constructed Wetland Treatment Systems: Metals Removal Design Innovations in Industrial Wastewater

Both the industrial and power utility sectors face increasingly stringent regulations for discharge of wastewater to surface waters. Owners are seeking treatment technologies that are effective, have low capital costs, and low maintenance requirements. Constructed Wetland Treatment Systems (CWTS) present a technology which uses natural biological processes to reduce the concentrations of constituents in wastewater. Reduction of metals in particular is a topic of concern for these industries. When Westar Energy required further polishing of flue gas desulfurization (FGD) wastewater, Burns & McDonnell designed a pilot scale CWTS to evaluate the reduction of metals. The pilot covered approximately two acres and treated approximately seven percent of the plant's FGD wastewater stream. Pilot project results were promising for removal of aluminum, barium, boron, chromium, iron, mercury, molybdenum, selenium, and vanadium. Following extensive water quality modeling, successful pilot results lead to the design and construction of a full scale CWTS for polishing of FGD wastewater.