Technical and Regulatory Guidance Document for Constructed Treatment Wetlands

Abstract : Constructed treatment wetlands are manmade wetlands built specifically to treat contaminants in surface water, groundwater, or waste streams such as leachate and acid mine drainage. The purpose of this document is to provide technical and regulatory guidance to help regulators, industry, consultants, and technology vendors understand, evaluate, and make informed decisions about the use of constructed treatment wetland systems. While there is extensive published literature on the subject, constructed wetland applications have generally been limited to the treatment of stormwater and municipal wastewaters. However, this technology is now emerging as a valid treatment option for a variety of waste streams, including acid mine water, remedial wastewaters, and agriculture waste streams. This guidance documents a number of current successful treatment systems, while it demonstrates the maturity of the technology in many emerging applications. The document describes the fundamental mechanisms of wetland contaminant removal and overall wetland functions. Degradation mechanisms are described in more detail in Phytotechnology Technical and Regulatory Guidance Document (PHYTO-2), published in April 2001. The Wetlands Team's approach in this document is to provide both scientific accuracy and basic understanding of these mechanisms regardless of the regulatory authority overseeing the site or regulating the contaminant. Simply stated, the technology is mature and tested. It is now being used in new applications and in some cases on new contaminants. This guidance provides detailed descriptions of the various contaminant treatment objectives, treatment efficiencies, and goals of different constructed wetland applications. Detailed, site-specific predesign criteria and conceptual designs are outlined, followed by final design, postconstruction activities, operation and maintenance, monitoring, and implementation costs.