ABSTRACT
Constructed wetlands have recently received considerable attention as a low-cost method for cleaning many types of wastewater. Though the concept of deliberately using wetlands for water purification has only developed within the last 20 years, in reality human societies have indirectly used natural wetlands for waste disposal for thousands of years. Man has dumped his wastes into nearby streams or wetland areas since prehistoric times. And as they do for natural ecosystems, wetlands processed these wastes and discharged relatively clean water.*
Constructed wetlands, in contrast to natural wetlands, are man-made systems that are designed, built, and operated to emulate natural wetlands or functions of natural wetlands for human desires and needs. Constructed wetlands as used for wastewater treatment may include swamps - wet regions dominated by trees, shrubs, and other woody vegetation, or bogs - low nutrient, acidic waters dominated by Sphagnum or other mosses - but most commonly they are designed to emulate marshes.
