College of Agriculture & Natural Resources
Environmental Science & Technology

Treatment wetlands

Wetlands are among the most productive ecosystems on Earth, support a diverse array of wildlife, and have been used for centuries to provide numerous services to humans, including water quality improvement floodwater management, and habitat for plants and animals. Wetland plants improve water quality by promoting settling of particulates, uptake of nutrients and metals, and supporting microbial communities important in chemical transformation and removal from water and sediments. The species composition and diversity of plant species also affects ecosystem function. Wetlands containing mixtures of plant species may be superior to monocultures in improving water quality or other ecosystem functions due to complementary resource use below or aboveground. Wastewater treatment wetlands are a well-established engineering practice for treating biochemical oxygen demand, suspended solids, and nutrients, as well as sequestering metals, degrading chlorinated organics and phenolics and removing pathogens. Constructed wetlands have been used to purify wastewaters of all types: industrial, urban runoff, municipal, agricultural, landfill leachate and institutional. Most often they are used as a secondary treatment system, especially in smaller communities and locations where the wetland can “polish” secondarily treated wastewater. In agricultural settings treatment wetlands are highly effective in improving water quality, although high concentrations of ammonium in runoff from some operations (silos, animal facilities) may kill wetland plants. Research in treatment wetlands include polishing wetlands after anaerobic digestion, wetlands for aquaculture, wetlands for treating runoff from grey water and the built environment, and treatment wetlands for storm water management. 

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