Constructed wetlands to decontaminate wastewater

Constructed wetlands are effective and reliable wastewater treatment systems. They have long been used to clean up wastewaters contaminated with conventional pollutants such as high nitrogen, phosphorus, or total suspended solids. Constructed wetlands are virtually the only means of cleaning up large volumes of water contaminated with very low levels of pollutants, e.g. toxic trace elements. They offer an efficient alternative to conventional water treatment systems because they are relatively inexpensive to construct and operate, easy to maintain, and quite tolerant of fluctuating hydrologic and contaminant loading rates. They have other benefits in that they provide green space, wildlife habitat, and recreational and educational areas. Furthermore, they are one of the most productive ecosystems in terms of biomass, especially when dominated by aquatic macrophytes. This is largely because of ample light, water, nutrients, and the presence of plants that have developed morphological and biochemical adaptations enabling them to take advantage of these optimum conditions. Our research has extended the use of constructed wetlands to include the remediation of waters contaminated with heavy metals and other toxic trace elements.