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Design Model for COD Removal in Constructed Wetlands Based on Biofilm Activity |
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| Authors: | C Polprasert N R Khatiwada J Bhurtel |
| Affiliation: | 1Prof., Envir. Engrg. Program, Asian Inst. of Technol., P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand.
2PhD Candidate, Envir. Engrg. Program, Asian Inst. of Technol., P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand. 3Res. Assoc., Envir. Engrg. Program, Asian Inst. of Technol., P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand. |
| Abstract: | Current design criteria for free-water-surface constructed wetlands are based on either empirical relationships or first-order reaction rates and do not emphasize the microbial activity. This study was conducted to evaluate the role of biofilm bacteria present in free-water-surface constructed wetland beds in the removal of organic matter. A kinetic model incorporating the biofilm kinetics and dispersion number was proposed to predict chemical oxygen demand removal in free-water-surface constructed wetlands. The model parameters were determined from laboratory experiments and from the literature. The proposed kinetic model satisfactorily predicted chemical oxygen demand removal efficiencies in a pilot-scale constructed wetland unit located in the tropics. A design chart and a design example based on the kinetic model are given. |
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