Energy and Emergy Analysis to Evaluate Sustainability of Small Wastewater Treatment Plants: Application to a Constructed Wetland and a Sequencing Batch Reactor — Oak Academic Publishing
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Energy and Emergy Analysis to Evaluate Sustainability of Small Wastewater Treatment Plants: Application to a Constructed Wetland and a Sequencing Batch Reactor
The aim of this study is to assess the sustainability of two wastewater treatment systems by energy and emergy analyses. The first system is a Sequencing Batch Reactor (SBR) which is a concrete and electricity dependent intensive process. The second is a constructed wetland, usually considered as an extensive process. The two studied facilities have similar treatment capacity and removal efficiencies. This study sheds new light on the comparison of wastewater treatment plants. We defined a new unit, the “Functional Efficiency Index” (or FEI) to describe the energetic efficiency of the facilities, expressed in kJ per year and per kg of removed COD. The energy analysis showed that, after its construction, the constructed wetland system uses only renewable energy, in marked contrast to the SBR, totally dependent on electricity which is considered here as a non renewable. The emergy analysis showed no significant differences between the two processes, but energy and emergy indices are in favour of the constructed wetland process and thus confirm its sustainability.
KeywordsConstructed WetlandEmergy AnalysisSBREnergySustainable Development
P. Griffin and J. Upton, “Constructed Wetlands: A Strategy for Sustainable Wastewater Treatment at Small Treatment Works,” Journal of the Chartered Institution of Water and Environmental Management, Vol. 13, 1999, pp. 441-446.
H. T. Odum, “Ecological Engineering and Self Organization,” W. Mitsch and S. Jorgensen, Eds., Ecological Engineering: An Introduction to Ecotechnology, Wiley & Sons, New York, 1991, pp. 79-101.
H. T. Odum, “Environmental Accounting: Emergy and Environmental Decision Making,” John Wiley & Sons, New York, 1996.
M. T. Brown and T. R. McClanaham, “Emergy Analysis Perpectives of Thailand and Mekong River Dam Proposals,” Ecological Modelling, Vol. 91, No. 1, 1996, pp. 105-130.
M. T. Brown and V. Buranakarn, “Emergy Indices and Ratios for Sustainable Material Cycles and Recycle Options,” Resources, Conservation and Recycling, Vol. 38, No. 1, 2003, pp. 1-22.
P. P. Franzese, et al., “Sustainable Biomass Production: A Comparison between Gros Energy Requirement and Emergy Synthesis Methods,” Ecological Indicators, Vol. 9, No. 5, 2009, pp. 959-970.
M. Nelson, “Wetland Systems for Bioregenerative Reclamation of Wastewater and Closed Systems to Developing Countries,” Life Support and Biosphere Science, Vol. 5, No. 3, 1998, pp. 357-369.
P. Vassallo, C. Paoli and M. Fabiano, “Emergy Required for the Complete Treatment of Municipal Wastewater,” Ecological Engineering, Vol. 35, No. 5, 2009, pp. 687- 694.
B. Chen, et al., “Emergy as Embodied Energy Based Assessment for Local Sustainability of a Constructed Wetland in Beijing,” Communications in Nonlinear Science and Numerical Simulation, Vol. 14, No. 2, 2009, pp. 622-635.
J. B. Zhou, et al., “Emergy Evaluations for Constructed Wetland and Conventional Wastewater Treatments,” Nonlinear Science and Numerical Simulation, Vol. 14, No. 4, 2010, pp. 1781-1789.
M. E. Arias and M. T. Brown, “Feasibility of Using Constructed Treatment Wetlands for Municipal Wastewater Treatment in the Bogota Savannah, Colombia,” Ecological Engineering, Vol. 35, No. 7, 2009, pp. 1070-1078.
S. C. Reed and D. S. Brown, “Subsurface Flow Wetlands: A Performance Evaluation,” Water Environment Research, Vol. 67, No. 2, 1995, pp. 244-248.
R. Haberl, “Constructed Wetlans: A Chance to Solve Wastewater Problems in Developing Countries,” Water Science and Technology, Vol. 40, No. 2, 1999, pp. 11-17.
P. Molle, et al., “How to Treat Raw Sewage with Constructed Wetlands: An Overview of the French Systems,” Water Science and Technology, Vol. 51, No. 9, 2005, pp. 11-21.
G. Merlin, J. L. Pajean and T. et Lissolo, “Performances of Constructed Wetlands for Municipal Wastewater Treatment in Rural Mountainous Area,” Hydrobiologia, Vol. 469, No. 1-3, 2002, pp. 87-98.
APHA, “Standard Methods for the Examination of Water and Wastewater,” 20th Edition, American Public Health Association, Washington D.C., 1998.
P. L. MacCarty, “Stoichiometry in Biological Reactions,” Progress in Water Technology, Vol. 7, 1975, pp. 157- 172.
C. P. L. Grady Jr., G. T. Daigger and H. C. Lim, “Biological Wastewater Treatment,” 2nd Edition, Dekker, New York, 1999.
B. Li and P. L. Bishop, “Microprofiles of Activated Sludge Floc Determined Using Microelectrodes,” Water Research, Vol. 38, No. 5, 2004, pp. 1248-1258.
S. Ulgiati and M. T. et Brown, “Emergy Accounting of Human Dominated, Large Scale Ecosystems,” Jorgensen, Ed., Thermodynamics and Ecological Modelling, Lewis Publisher, London, 2001.
“Emergy Simulator: An Open Source Simulation Platform Dedicated to System Ecology and Emergy Studies,” E. Valyi, R et Ortega, E. Ortega, S. Ulgiati and S. P. Unicamp, Eds., Proceedings of 4th Biennal Internationnal Workshop, Advances in Energy Studies, Campinas, 2004, pp. 349-360.
F. Meillaud, J. B. Gay and M. T. Brown, “Evaluation of a Building Using the Emergy Method,” Solar Energy, Vol. 79, No. 2, 2005, pp. 204-212.
R. M. Pulselli, et al., “Specific Emergy of Cement and Concret: An Energy Based Appraisal of Building Materials and Their Transport,” Eco-Industrial, Vol. 8, 2008, pp. 647-656.
M. T. Brown and E. et Bardi, “Emergy of Ecosystems,” Handbook of Emergy Evaluation, University of Florida, Gainsville, 2001.
U. Geber and J. et Bjorklund, “The Relationship between Ecosystem Services and Purchased Input in Swedish Wastewater Treatment Systems: A Case Study,” Ecological Engineering, Vol. 18, No. 1, 2001, pp. 39-59.
H. Brix, “Do Macrophytes Play a Role in Constructed Treatment Wetlands?” Water Science and Technology, Vol. 35, No. 5, pp. 11-17.
M. T. Brown and E. et Bardi, “Emergy Indices and Environmental Loading of Electricity Production Systems,” Journal of Cleaner Production, Vol. 10, No. 4, 2002, pp. 321- 334.
A. D. Siracus and A. D. et La Rosa, “Design of a Constructed Wetland for Wastewater Treatment in a Sicilian Town and Environmental Evaluation Using the Emergy Analysis,” Ecological Modelling, Vol. 197, No. 3-4, 2006, pp. 490- 497.
M. Nelson, et al., “Living of the Land: Resource Efficiency of Wetland Wastewater Treatment,” Advanced Space Research, Vol. 27, No. 9, 2001, pp. 1547-1556.
D. P. L. Rousseau, P. A. Vanrolleghem and N. et De Pauw, “Model-Based Design of Horizontal Subsurface Flow Constructed Treatment Wetlands: A Review,” Water Research, Vol. 38, No. 6, 2004, pp. 1484-1493.
C. Cao and X. et Feng, “Distribution of Emergy Indices and Its Application,” Energy Fuel, Vol. 21, No. 3, 2007, pp. 1717-1723.