1 Department of Water Supply and Sanitation, Faculty of Environmental Engineering, National University of Civil Engineering, Vietnam

2 Department of Environmental Engineering, Thai Nguyen University, Tan Thinh Ward, Thai Nguyen, Vietnam

3 Department of Civil Engineering, University of Ottawa, 161 Louis Paster Pvt., Ottawa k1N 6N5, Canada


Constructed wetlands have not been commonly used in Vietnam due to the lack of information in the selection of proper types of constructed wetlands, type of reeds, design parameters and performance efficiency, in tropical climates. This paper focuses on Canna generalis, which is a common reed and easy to grow both in water and wet land conditions. Two kinds of hybrid constructed wetlands were employed, including Facultative pond combined with free water sub-surface constructed wetlands system and horizontal subsurface flow combined with Aerobic pond system. It was found that the ponds played an important role in the hybrid system performance and enhanced the performance of constructed wetlands. The pollutant removal efficiencies of the hybrid systems were all higher than the single constructed wetlands. The BOD5, TSS, NH4-N and PO4-P removal efficiencies averaged 81%, 85%, 93% and 77%, respectively for the hybrid horizontal subsurface flow constructed wetlands system operated at a hydraulic loading rate of 0.075 m/day, while they were 89%, 97%, 97%, and 68%, respectively for the hybrid free water sub-surface constructed wetlands system operated at a hydraulic loading rate of 0.1 m/day. The removal rate constants (kBOD5, kNH4-N, kPO4-P) of the experimental hybrid constructed wetlands were similar to those in previous studies. However, these constants were higher for the hybrid free water subsurface constructed wetlands because of the modified structure flow of the free water subsurface constructed wetlands applied in this study, compared to conventional ones, as well as the additional benefits of the ponds in the hybrid systems.

Graphical Abstract

Pollutant removal by Canna Generalis in tropical constructed wetlands for domestic wastewater treatment


  • Canna Generalis grew with high total biomass and performed well in pollutant removal in tropical constructed wetlands;
  • Modified flow structure of free water sub-surface constructed wetlands and additional facultative pond help the hybrid constructed wetlands perform better;
  • High values of removal rate constant “k” do not necessarily indicate high removal efficiency;
  • High temperature (>35oC) affected the performance of hybrid tropical CWs due to affecting bacteria activity and humidity.


Du, L.; Chen, Q.; Liu, P.; Zhang, X.; Wang, H.; Zhou, Q.; Xu, D.; Wu, Z., (2017). Phosphorus Removal Performance and Biological Dephosphorization Process in Treating Reclaimed Water by Integrated Vertical-Flow Constructed Wetlands (IVCWs). Bioresour. Technol. 243: 204-211 (8 Pages).

Huang, J.; Cai, W.; Zhong, Q.; Wang, S., (2013). Influence of temperature on micro-environment, plant ecophysiology and nitrogen removal effect in subsurface flow constructed wetland. Ecol. Eng. 60: 242–248 (7 pages).

Huang, J.; Wang, S.; Yan, L.; Zhong, Q., (2010). Plant photosynthesis and its influence on removal efficiencies in constructed wetlands. Ecol. Eng. 36: 1037–1043 (7 pages).

Jones, R.D; Hood, M.A., (1980). Effect of Temperature, pH, Salinity and Inorganic nitrogen on the rate of ammonium oxidation by nitrifiers isolated from wetlands environment. Microb. Ecol. 6: 339-347 (9 pages).

Kadlec, R. H.; Knight, R. L., (1996). Treatment wetlands, 1st Edition. CRC Press, Boca Raton, Florida.

Kadlec, R.H.; Wallace, S.D., (2008). Treatment Wetlands, 2nd Edition. CRC Press, Boca Raton, Florida.

Kadlec, R.H., (2009). Comparison of free water and horizontal subsurface treatment wetlands, Ecol. Eng. 35: 159–174 (15 pages).

Kayombo, S.; Mbwette, T.; Katima, J.; Ladengaard N.; Jorgensen S., (2004). Waste Stabilization Ponds and Constructed Wetlands Design Manual. Dar es Salaam, TZ/Copenhagen, DK: UNEP-IETC/Danida (59 pages).

Kim, D.G.; Park, J.; Lee, D.; Kang, H., (2011). Removal of nitrogen and phosphorus from the effluent of a secondary wastewater treatment plant using a pond-marsh wetland system. Water Air Soil Pollut. 214(1): 37-47 (11 pages).

Konnerup, D., Koottatep, T., Brix, H., (2009). Treatment of domestic wastewater in tropical, subsurface flow constructed wetlands planted with Canna and Heliconia. Ecol. Eng. 35 (2): 248–257 (9 pages).

Ngo, T.D.T.; Konnerup, D.; Schierup, H.-H.; Nguyen, H.C.; Le, A.T.; Brix H., (2010). Kinetics of pollutant removal from domestic wastewater in a tropical horizontal subsurface flow constructed wetland system: Effects of hydraulic loading rate”, Ecol. Eng. 36: 527–535 (9 pages).

Piwpuan, N.; Jampeetong, A.; Brix, H., (2014). Ammonium tolerance and toxicity of Actinoscirpus grosses – A candidate species for use in tropical constructed wetland systems. Ecotox. Environ. Safe. 107: 319–328 (10 pages).

Ojoawo, S. O.; Udayakumar, G.; Naik, P., (2015).  Phytoremediation of Phosphorus and nitrogen with Canna x generalize Reeds in Domestic Wastewater through NMAMIT Constructed Wetland. Aquat. Procedia 4:349 – 356 (8 pages).

Shitu, A.; Izhar, S.; Tahir, T.M., (2015). Sub-critical water as a green solvent for the production of valuable materials from agricultural waste biomass: A review of recent work. Global J. Environ. Sci. Manage., 1(3): 255-264 (10 pages).

Singh, S.; Haberl, R.; Moog, O.; Shrestha, R.R.; Shrestha, P.; Shrestha, R., (2009). Performance of an anaerobic baffled reactor and hybrid constructed wetland treating high-strength wastewater in Nepal-a model for DEWATs. Ecol. Eng. 35: 654-660 (7 pages).

Tran, D.H., (2006). Urban Wastewater treatment, 1st Edition. Science and Engineering Publisher, Hanoi.

USEPA, (2000). Manual constructed wetlands treatment of municipal wastewaters- National Risk Management Research Laboratory, Office of Research and Development,  U.S.Environmental Protection Agency, Cincinnati, Ohio 45268-EPA/625/R-99/010.

Vohla, C.; Kõiv, M.; Bavor, H.J.; Chazarenc, F.; Mander Ü., (2011). Filter materials for phosphorus removal from wastewater in treatment wetlands—a review. Ecol. Eng. 37: 70-89 (10 pages).

Vymazal, J., (2007). Removal of nutrients in various types of constructed wetlands. Sci. Total Environ. 380: 48-65 (8 pages).

Vymazal J.; Kropfelová, L., (2008). A three-stage experimental constructed wetland for treatment of domestic sewage: First 2 years of operation. Ecol. Eng. 37 (2011): 90–98 (9 pages).

Vymazal, J., (2009). The use constructed wetlands with the horizontal sub-surface flow for various types of wastewater. Ecol. Eng. 35 (1): 1–17 (18 pages).

Watson, J.T.; Reed, S.C.; Kadlec, R.H.; Knight, R. L.; Whitehouse A.E., (1989). Constructed Wetlands for Wastewater Treatment, Ed. DA Hammer, Lewis Publishers, CRC Press, Boca Raton, Florida.

Wen, Y.; Chen, Y.; Zheng, N.; Yang, D.; Zhou, Q., (2010). Effects of plant biomass on nitrate removal and transformation of carbon sources in subsurface-flow constructed wetlands. Bioresour. Technol. 101: 7286–7292 (7 pages).

World Bank. 2013. Vietnam Urban Wastewater Review. Washington, DC. © World Bank.

Yigitcanlar, T.; Dizdaroglu, D., (2015). Ecological approaches in planning for sustainable cities: A review of the literature. Global J. Environ. Sci. Manage. 1(2):159-188 (30 pages).

Zhang, D.Q.; Gersberg, R.M.; Tan, S.K., (2009). Constructed wetlands in China. Ecol. Eng. 35: 1367–1378 (12 pages).

Zhang, D.Q.; Tan, S.K.; Gersberg, R.M.; Zhu, J.F.; Sadreddini, S.; Li, Y.F., (2012). Nutrient removal in tropical subsurface flow constructed wetlands under batch and continuous flow conditions. J. Environ. Manage. 96: 1-6 (6 pages).

Zhang, D.Q.; Jinadasa, K.; Gersberg, R. M.; Liu, Y.; Ng, W. J.; Tan, S.K., (2014). Application of constructed wetlands for wastewater treatment in developing countries: A review of recent developments (2000-2013). J. Environ. Manage. 141: 116-131 (16 pages).

Zurita, F.; De Anda, J.; Belmont, M.A., (2009). Treatment of domestic wastewater and production of commercial flowers in vertical and horizontal subsurface-flow constructed wetlands. Ecol. Eng. 35 (5): 861–869 (9 pages). 

Letters to Editor

GJESM Journal welcomes letters to the editor for the post-publication discussions and corrections which allows debate post publication on its site, through the Letters to Editor. Letters pertaining to manuscript published in GJESM should be sent to the editorial office of GJESM within three months of either online publication or before printed publication, except for critiques of original research. Following points are to be considering before sending the letters (comments) to the editor.

[1] Letters that include statements of statistics, facts, research, or theories should include appropriate references, although more than three are discouraged.
[2] Letters that are personal attacks on an author rather than thoughtful criticism of the author’s ideas will not be considered for publication.
[3] Letters can be no more than 300 words in length.
[4] Letter writers should include a statement at the beginning of the letter stating that it is being submitted either for publication or not.
[5] Anonymous letters will not be considered.
[6] Letter writers must include their city and state of residence or work.
[7] Letters will be edited for clarity and length.