Transcript Constructedwetlands

Constructed Wetlands and
Wastewater Treatment
Scott Stine
SWES 574
Types of Constructed Wetlands
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Surface Flow Wetlands (SF)
– similar to natural wetlands
– free floating, emergent, and submerged
plants are used
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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
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Additional Secondary Treatment
Tertiary Treatment
Onsite Wastewater Treatment
– alternative to municipal sewage treatment
– used in animal feeding operations
Microorganisms
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Bacteria
– Coliforms, Enterococci, C. perfringens
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Viruses
– Coliphage
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Parasites
– Cryptosporidium, Giardia
Removal Processes
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Most processes are enhanced by
vegetation
Processes include:
– Filtration
– Adsorption
– Predation
– UV light
– Sedimentation
SSF vs. SF
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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
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Some bacteria are able to reproduce on
some plant surfaces
– Enterococci
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Spore forming pathogens may be
released by precipitation
– Cryptosporidium
– Giardia