Hydraulic Model Comparison of Vertical-flow Regimes in Constructed Wetlands
Vertical-flow treatment wetlands have come into use because of their ability to provide highlevel secondary and tertiary wastewater treatment at a fraction of the land use of horizontal subsurface flow or free water surface wetlands. The flow regime typically selected is vertically downward, allowing wastewater to infiltrate through the system by gravity. However, recent research suggests that upflow wetlands may provide high-level treatment in terms of nitrogen removal. This paper compares upflow and downflow wetlands, focusing on the hydraulic function and natural aeration potential of each flow regime. Using HYDRUS-2D, a flow simulation and sensitivity analysis of plant uptake (Feddes parameters) and oxygen transport (kinetic parameters) are performed on hypothetical upflow and downflow wetland configurations. Comparison simulations of wetland mesic and prairie vegetation show that true wetland vegetation will thrive in saturated conditions and allow more oxygen transfer into the soil. The kinetics indicate that dissolved oxygen within the wastewater will be consumed very rapidly, reaching less than 30% of the soil depths in both the upflow and downflow cases. Adding gaseous diffusion of oxygen from the soil surface results in oxygen transfer down through 40% of the depth and shows that the upflow hydraulic regime may have better aeration capacity than downflow. This data may useful for choosing the hydraulic regimen, plant type and wetland bed depth to make nitrification and denitrification in constructed wetlands more effective and efficient. Better design of constructed wetlands will enable their use and benefits in developing communities in need of economic, environmentally-based wastewater treatment.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
Document Type: Research Article
Publication date: 2007-10-13
More about this publication?
- Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.
WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
- Subscribe to this Title
- Membership Information
- About WEF Proceedings
- WEFTEC Conference Information
- Learn about the many other WEF member benefits and join today
- Ingenta Connect is not responsible for the content or availability of external websites