Constructed Wetland Treatment System
Des Moines, Iowa

Metro Waste Authority (MWA) desired to develop and implement a cost-effective, “user-friendly,” and environmentally sound leachate treatment sytem for Metro Park East Landfill. Foth and J.F. New & Associates were retained to design a constructed wetland treatment system to meet MWA’s objectives.

The design for the treatment system includes a constructed wetland, use of spray irrigation or land application of the treated leachate, and provisions for truck hauling of treated (or untreated) leachate to a local wastewater treatment plant.

Challenges:

• Leachate production in a landfill has seasonal variations and wetland systems do not function during the winter season. To account for these factors, the system design includes storage, recir-culation and truck hauling options.
• MWA wishes for this system to ultimately result in zero discharge of leachate.
• The wetland system requires an amendment to the Iowa Department of Natural Resources’ Sanitary Disposal project permit. In addition, the area upon which the system will be constructed must receive a conditional use permit from Polk County.

Benefits:

• Provides a long-term cost-effective treatment system which improves MWA’s ability to remain competitive.
• Enhances MWA’s role as a partner with local environmental, educational and conservation programs.