Greenhouse gas emissions from waste stabilisation ponds in Western Australia and Quebec (Canada).
Waste stabilisation ponds (WSPs) are highly enriched environments that may emit large quantities of greenhouse gases (GHG), including CO2, CH4 and N2O. However, few studies provide detailed reports on these emissions. In the present study, we investigated GHG emissions from WSPs in Western Australia and Quebec, Canada, and compared emissions to WSPs from other climatic regions and to other types of aquatic ecosystems. Surface water GHG concentrations were related to phytoplankton biomass and nutrients. The CO2 was either emitted or absorbed by WSPs, largely as a function of phytoplankton dynamics and strong stratification in these shallow systems, whereas efflux of CH4 and N2O to the atmosphere was always observed albeit with highly variable emission rates, dependent on treatment phase and time of the day. The total global warming potential index (GWP index, calculated as CO2 equivalent) of emitted GHG from WSPs in Western Australia averaged 12.8 mmol m(-2) d(-1) (median), with CO2, CH4 and N2O respectively contributing 0%, 96.7% and 3.3% of the total emissions, while in Quebec WSPs this index was 194 mmol m(-2) d(-1), with a relative contribution of 93.8, 3.0 and 3.2% respectively. The CO2 fluxes from WSPs were of the same order of magnitude as those reported in hydroelectric reservoirs and constructed wetlands in tropical climates, whereas CH4 fluxes were considerably higher compared to other aquatic ecosystems. N2O fluxes were in the same range of values reported for WSPs in subtropical climate.
Institut national de la recherche scientifique, Centre Eau Terre Environnement, 490 rue de la Couronne, Quebec, QC G1K 9A9, Canada; School of Civil, Environmental and Mining Engineering, The University of Western Australia, 35 Stirling Highway M015, Crawley, WA 6009, Australia. Electronic address: glaz.patricia@gmail.com.
Patricia
P
Glaz
Institut national de la recherche scientifique, Centre Eau Terre Environnement, 490 rue de la Couronne, Quebec, QC G1K 9A9, Canada; Groupe de Recherche Interuniversitaire en Limnologie et en environnement aquatique (GRIL), Université de Montréal, Montréal, QC H3C 3J7, Canada.
Maciej
M
Bartosiewicz
Institut national de la recherche scientifique, Centre Eau Terre Environnement, 490 rue de la Couronne, Quebec, QC G1K 9A9, Canada; Groupe de Recherche Interuniversitaire en Limnologie et en environnement aquatique (GRIL), Université de Montréal, Montréal, QC H3C 3J7, Canada.
Isabelle
I
Laurion
School of Civil, Environmental and Mining Engineering, The University of Western Australia, 35 Stirling Highway M015, Crawley, WA 6009, Australia.
Elke S
ES
Reichwaldt
Groupe de Recherche Interuniversitaire en Limnologie et en environnement aquatique (GRIL), Université de Montréal, Montréal, QC H3C 3J7, Canada; Département des Sciences Biologiques, Université de Montréal, Montréal, QC H2V 2S9, Canada.
Roxane
R
Maranger
School of Civil, Environmental and Mining Engineering, The University of Western Australia, 35 Stirling Highway M015, Crawley, WA 6009, Australia.
Anas
A
Ghadouani
D017752:Greenhouse Effect; D008697:Methane; D061005:Ponds; D011792:Quebec; D014904:Western Australia
D008697:Methane
CH(4); CO(2); Diffusive flux; Global warming potential; Greenhouse gases; N(2)O; Spatiotemporal variability; Waste stabilisation ponds; Wastewater treatment