1. Constructed Wetlands and Wastewater Treatment Scott Stine SWES 574

2. Types of Constructed Wetlands n Surface Flow Wetlands (SF) –similar to natural wetlands –free floating, emergent, and submerged plants are used n Subsurface Flow Wetlands (SSF) –water flows below surface of support media –emergent plants that are tolerant of water saturated soils are used

3. Wastewater Treatment Uses n Additional Secondary Treatment n Tertiary Treatment n Onsite Wastewater Treatment –alternative to municipal sewage treatment –used in animal feeding operations

4. Microorganisms n Bacteria –Coliforms, Enterococci, C. perfringens n Viruses –Coliphage n Parasites –Cryptosporidium, Giardia

5. Removal Processes n Most processes are enhanced by vegetation n Processes include: –Filtration –Adsorption –Predation –UV light –Sedimentation

6. SSF vs. SF n What are the objectives of the constructed wetland? n Some considerations: –SSF remove pathogens more efficiently than SF –SF allow more biodiversity and habitats –SSF minimize pests such as mosquitoes

7. Concerns n Some bacteria are able to reproduce on some plant surfaces –Enterococci n Spore forming pathogens may be released by precipitation –Cryptosporidium –Giardia