|Wednesday, June 02|
Study of the Degradation of the Rejection Capacity of Oily Water Membrane Filtration Systems Using Experimental and Computational Fluid Dynamics
* Mohamed Echakouri, University of Regina, Canada
Amgad Salama, Canada
Amr Henni, Canada
Produced water treatment using pressure-driven filtration membrane technology is promising technique but is constrained by the issue of fouling. Fouling is the deposition of scattered pollutants on the surface of the membrane, which decreases the area available for filtration and reduces the permeation flux. Although this is readily obvious when dispersals are solid contaminants, it is less evident when dispersals are droplets of another fluid that are immiscible to a continuous one. Fluids can deform, pinch, and shape to the pore. This challenges the suggestion and practice of several researchers to apply to filtration of fluid emulsions the pore clogging processes, initially designed for the filtration of solid emulsions. In order to explore this subject, in this work, we conduct experimental and numerical studies to examine whether the blocking mechanisms can still adhere to the filtration of fluid emulsions. The experimental set-up requires the application of three types of polymers and three distinct oils. The findings attained indicate that, compared to what would happen if the dispersals were solid particles, the oil content in the permeate rise with time. In addition, the membrane’s rejection capacity reduces overtime, meaning that as fouling progresses, more oil permeates. Again, this is opposed to the observed practice of solid emulsion filtration where, as fouling develops, the solid content in the permeate often decreases. Three scenarios have been numerically investigated using computational fluid dynamics methods to validate this behaviour. The numerical analysis indicates that larger droplets that would not otherwise permeate undergo permeation when a pore opening is filled with oil. This supports the idea that the pores that are filled or blanketed with oil do not limit oil from permeation as fouling develops; moderately, they ease its passage and reduce the membrane’s selectivity. Fluid emulsion filtration is radically distinct from that of solid emulsions. Fluids can deform, squeeze, and take the shape of the pores. In this case, the parameter which determines the selectivity of the membranes is given by interfacial tension forces.
The patchwork governance of the Rideau Canal: Balancing usage priorities in a jurisdictional quagmire
* Christine Beaudoin, University of Ottawa, Canada
Jordanna N. Bergman, Canada
Isha Mistry, Canada
"The Rideau Canal National Historic Site exemplifies the challenges of managing multiple water usages in interconnected freshwater systems. We describe its governance structure as “patchwork” because it consists of unclear and overlapping jurisdictions that share authority over various parts of the system. This fragmentation has created a complex governance regime which can make it difficult for users and authorities to safeguard the system’s environmental integrity, especially in the context of competing stakeholder interests. Parks Canada, the federal management agency and primary steward of the Rideau Canal, is tasked with maintaining the system for navigation, water flows, and historical and cultural heritage, as well as ecological health. This is no easy task considering the need to balance multiple usages, external development pressures, and conservation within a complex governance landscape. Indeed, this system must be managed such that it meets a multitude of federal and provincial legal requirements (e.g., Historic Canal Regulations, Species at Risk Act, Ontario Water Resources Act, Conservation Authorities Act). The Rideau Canal spans 13 municipalities and counties, and two watersheds each with their respective Conservation Authorities. Governance of the system not only encompasses the actions of different levels of government, but also that of other actors like recreational user groups, community groups, non-governmental organizations, and businesses. Parks Canada is additionally committed to building relationships with Indigenous communities in the Rideau corridor. Management of the Rideau Canal ranges from local to global scales, as the Rideau Canal is subject to UNESCO requirements to maintain its status as a World Heritage Site. To date, there has been little work to investigate the roles of different governance actors along the Rideau corridor; thus, there is a need to analyze this jurisdictional quagmire and competing usages of the waterway to build adaptive capacity in the system and work towards integrated water governance. Using the Rideau Canal as a case study, we outline overlaps in the jurisdictional and legislative landscape, as well as the inherent tensions between historical-economic-social priorities and the need to protect freshwater ecosystems. Our examination of this complex waterway has revealed the social-ecological mismatch between (1) the Rideau Canal as an interconnected, freshwater ecosystem with ecologically and economically significant wildlife and (2) the fragmented socio-political structure that governs the usage of this system. Although this mismatch can undermine system resilience and lead to both gaps and inefficiencies, it showcases opportunities for innovative governance solutions. While total legislative reform is not a realistic option, some challenges could be addressed through better collaboration and coordination of various actors. We conclude by exploring opportunities for improved multi-scalar and multi-stakeholder water governance. The socio-cultural features of the Rideau Canal create a rich foundation for re-envisioning waterways of the future – waterways that respect and celebrate the past, while simultaneously recognizing that the world is changing and our systems must benefit both users and the environment."
Assessment of the ability of the Standardized Precipitation Evapotranspiration Index (SPEI) to model historical streamflow in watersheds of Western Canada
* Sunil Gurrapu, National Institute of Hydrology, Canada
Jeannine-Marie St-Jacques, Canada
David J. Sauchyn, Canada
Kyle R. Hodder, Canada
Knowledge of present-day spatial and temporal distribution of water resources is vital for successful water management and policies for planned adaptation to climate change. Measured quantities of hydroclimatic variables, including precipitation, evapotranspiration, streamflow, etc., are the primary indicators of water availability, and indices derived using several such primary variables provide a means to express water availability across a range of spatio-temporal scales. In this study, the ability of one such multi-scalar index, the Standardised Precipitation Evapotranspiration Index (SPEI), computed at a range of timescales, was examined to see how well it could model historically-observed warm season monthly and annual streamflow in 24 natural-flowing watersheds of western Canada. The empirical relationships between the SPEI, computed at 1-, 3-, 6-, 9-, 12- and 24- month timescales, and monthly and annual streamflow were analyzed, showing significant correlations for all watersheds. The timescale of the SPEI with the strongest correlations varied seasonally. Based on these results, SPEI-based principal component regression (PCR) equations were calculated to model warm season monthly and annual historical streamflow. These PCR equations are able to adequately capture historical streamflow in these watersheds. Annual streamflow variability was better captured (mean R_adj^2 = 0.46) than monthly variability (mean R_adj^2 = 0.30 over March-October). Summer and fall streamflow variability was better captured (mean R_adj^2 = 0.42 over June-September) than spring variability (mean R_adj^2 = 0.15 over March-April).
Development of long-term forecasting model to assess current and future water flows in Canada for energy supply sectors
* Amit Kumar, University of Alberta, Canada
Thomas Patrick, Canada
Matthew Davis, Canada
Qinzhi Liu, Canada
Ankit Gupta, Canada
Nikhil Agrawa, Canada
Available data on water use in Canada is often provided at the national, multi-regional, or major sectoral level, leaving an information gap on sub-sectoral and provincial water use. Energy sectors in particular are experiencing various technologic shifts which will impact the way they use water, thus the data gap is important to address. This research disaggregates existing Canadian water use data to create a single dataset on water use at the sub-sector level in each province in 2015. Sankey diagrams have been developed illustrating the flow of water between surface versus ground water sources, sub-sectoral and provincial users, and discharge versus consumption. The dataset has also been used to develop a Canada-wide Water Evaluation and Planning (WEAP) model of the oil and gas and electricity generation sectors, covering the years 2005-2050. Sectoral activity within the model has been further disaggregated covering 94 rivers supplying 201 major demand sites. Long-term energy sector technology change and the associated water use impacts have been evaluated for these two sectors. Results will provide policymakers with new disaggregated data on water use in Canada, as well as detailed projections for water use in the oil and gas extraction and electricity generation sectors.