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Published on: November 18, 2015
Performance modeling of subsurface-flow constructed wetlands systems
M F Dahab1, R Y Surampalli, W Liu
1Department of Civil Engineering, University of Nebraska-Lincoln, 68588-0531, USA.
Summary
Constructed wetlands (CW) effectively treat wastewater from small communities, with BOD5 and NH3-N removal approximated by first-order kinetics. However, TP removal kinetics were unclear, and observed removal rates were lower than expected.
Area of Science:
- Environmental Engineering
- Water Treatment Technologies
- Ecological Engineering
Background:
- Constructed wetlands (CW) are increasingly utilized for wastewater treatment.
- Small community systems require efficient and reliable treatment solutions.
- Subsurface flow CW systems offer a potential solution for decentralized wastewater management.
Purpose of the Study:
- To evaluate the effectiveness of a subsurface flow constructed wetland (CW) system for a small community wastewater treatment.
- To compare field data with prediction models for key pollutant removal.
- To analyze the removal kinetics of biochemical oxygen demand (BOD5), ammonia nitrogen (NH3-N), and total phosphorus (TP).
Main Methods:
- Extensive biweekly monitoring of a CW system from June 1996 to December 2000.
- Application of prediction models for soluble CBOD5, NH3-N, and TP removal.
- Comparison of model predictions with field-collected data.
- Kinetic analysis of pollutant removal rates.
Main Results:
- BOD5 and NH3-N removal approximated first-order kinetics.
- TP removal kinetics were not clearly defined by the models or data.
- Regressed reduction rate constants from field data were lower than reported literature values.
- The CW system demonstrated effectiveness in treating wastewater for a small community.
Conclusions:
- Subsurface flow CW systems can be effective for small community wastewater treatment.
- First-order kinetics adequately describe BOD5 and NH3-N removal.
- Further research is needed to clarify TP removal kinetics in CW systems.
- Observed pollutant reduction rates in this study suggest site-specific factors influence CW performance.
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