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Learn about different types of constructed wetlands, the role of microorganisms, removal processes, and the comparison between surface flow and subsurface flow wetlands. Understand the benefits, concerns, and efficiency factors involved in utilizing constructed wetlands for wastewater treatment.
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Constructed Wetlands and Wastewater Treatment Scott Stine SWES 574
Types of Constructed Wetlands • Surface Flow Wetlands (SF) • similar to natural wetlands • free floating, emergent, and submerged plants are used • Subsurface Flow Wetlands (SSF) • water flows below surface of support media • emergent plants that are tolerant of water saturated soils are used
Wastewater Treatment Uses • Additional Secondary Treatment • Tertiary Treatment • Onsite Wastewater Treatment • alternative to municipal sewage treatment • used in animal feeding operations
Microorganisms • Bacteria • Coliforms, Enterococci, C. perfringens • Viruses • Coliphage • Parasites • Cryptosporidium, Giardia
Removal Processes • Most processes are enhanced by vegetation • Processes include: • Filtration • Adsorption • Predation • UV light • Sedimentation
SSF vs. SF • What are the objectives of the constructed wetland? • Some considerations: • SSF remove pathogens more efficiently than SF • SF allow more biodiversity and habitats • SSF minimize pests such as mosquitoes
Concerns • Some bacteria are able to reproduce on some plant surfaces • Enterococci • Spore forming pathogens may be released by precipitation • Cryptosporidium • Giardia