This course provides the proper perspective on the appropriate use, design, and performance of constructed wetlands. For some applications, they are an excellent option because they are low in cost and in maintenance requirements, offer good performance, and provide a natural appearance, as well as ecological benefits. In other applications, such as large urban areas with large wastewater flows, they may not be at all appropriate due to their land requirements.

Constructed wetlands are especially well suited for wastewater treatment in small communities where inexpensive land is available and skilled operators are hard to find and keep.

Constructed wetlands are artificial wastewater treatment systems consisting of shallow (usually less than 1 m deep) ponds or channels which have been planted with aquatic plants and which rely upon natural microbial, biological, physical, and chemical processes to treat wastewater. They typically have impervious clay or synthetic liners and engineered structures to control the flow direction, liquid detention time, and water level. Depending on the type of system, they may or may not contain an inert porous media such as rock, gravel, or sand.

Constructed wetlands have been used to treat a variety of wastewaters including urban runoff, municipal, industrial, agricultural, and acid mine drainage. However, the scope of this course is limited to constructed wetlands that are the major unit process in a system to treat municipal wastewater. While some degree of pre- or post- treatment will be required in conjunction with the wetland to treat wastewater to meet stream discharge or reuse requirements, the wetland will be the central treatment component. The course material is based entirely on the EPA Manual EPA/625/R-99/010: Constructed Wetlands Treatment of Municipal Wastewaters.

At the conclusion of this course, the learner will have a better understanding of the Constructed Wetlands Treatment of Municipal Wastewaters as well as an understanding of the following topics:

• When to use constructed wetlands
• Constructed wetlands for treatment of municipal wastewaters
• Modeling performance of constructed wetlands
• Free water surface and vegetated submerged wetlands
• Construction, operation, and maintenance procedures
• Capital and recurring costs of constructed wetlands