Peatlands comprise of approximately half of the Athabasca oil sands region, many of which overlay some of the world’s largest bitumen deposits where surface mining for this resource has permanently altered the landscape. By law, companies must reclaim disturbed landscapes into functioning ecosystems including integrated upland-wetland systems with the objective of forming sustainable peat-forming wetlands. This thesis presents six years (2013 – 2018) of water balance and associated salinity data from one of the two existing constructed upland-wetland systems, the Sandhill Fen Watershed (SFW), a 52-ha upland-wetland built on soft tailings to evaluate the hydrological and hydrochemical performance and its potential to be self-sustaining. Following a considerable decrease in hydrological management, the dominant water balance components changed from primarily horizontal (inflow and outflow) to vertical fluxes (precipitation and evapotranspiration) which increased inundation, encouraged salt accumulation and changed plant communities. Results suggest that current conditions are not favourable for fen-peatland development as marsh-like conditions have developed, limiting water conserving functions and the ability to persist long-term in a changing climate. In terms of winter processes, topography currently controls snow accumulation, redistribution and melt at SFW while the role of vegetation in these processes is expected to increase as it continues to develop. Runoff ratios of snowmelt from hillslopes were drastically different than those previously reported for reclaimed peatland watersheds highlighting the influence of different soil materials used during construction. Under various climate change scenarios of a warmer and wetter climate, results from the Cold Regions Hydrological Model indicate that the influence of winter processes will decrease, potentially putting reclaimed systems at greater risk of moisture stress. Substantial hydrochemical changes have occurred as salinity was relatively low at the study onset as high volumes of inflow and outflow prevented ion accumulation. Over time, salinity continued to increase year-over-year throughout SFW from 2013 to 2018 in the wetland and margin areas. This increase in site-wide salinity was attributed to the shift in dominant water balance fluxes, changes in water table position and increased mixing of SFW waters with deeper saline groundwater that underlies the system. Based on its current conditions, it is unlikely that SFW will support peat-forming vegetation. It is recommended that design strategies shift to incorporate characteristics found in undisturbed saline peatlands that are capable of supporting peat-forming vegetation in a saline environment. / Thesis / Doctor of Philosophy (PhD) / A better understanding of the hydrological functioning of reconstructed peatlands in the Athabasca oil sands region is required as it is a novel approach in this region and there is potential for thousands of hectares of land that will require this reclamation in the future. Due to their recent establishment potential trajectories of constructed peatlands have yet to be fully analyzed as only recently has sufficient data been collected to evaluate the hydrological and hydrochemical functioning and provide insight on its overall success. While design strategies may seem sound, these constructed systems are completely human-made and it is unclear how they will develop and function in a highly disturbed landscape. Thesis results suggest that current conditions are not favourable to sustain a peatland as marsh-like conditions have developed which will limit its ability to persist long-term in a dry and changing climate. It is recommended that design strategies shift to incorporate characteristics found in undisturbed saline peatlands that are capable of supporting peat-forming vegetation in a saline environment. Due to the many challenges associated with reclamation in this region, lessons learned from this pilot project will help guide future peatland construction.

Being absent from things or places for a period of time, we try to connect by revisiting our memories. There is always a vivid remembrance of certain objects or surroundings, but when we try to connect them, the truth in our mind deviates from the reality. The disintegration of the memories and the morphing of our imagination create a different reality in our minds that we begin to believe, considering that the truth becomes almost completely abstracted and obscured as time passes.

Degradation of surface water quality by excess nutrients in stormwater is a substantial environmental and economic problem in the U.S. Phosphorus (P) is often the limiting nutrient for harmful algal blooms and the best target to prevent degradation. Natural treatment strategies such as constructed wetlands (CW) demonstrate effective and economical P management but obstacles exist to implementation. Biological P removal has large land requirements that limit the use of best management practices (BMP) in high land-value areas. Various BMP also utilize sorption processes (SP) for P removal but variations in performance and finite sorption capacity limit SP as a viable long-term removal strategy. However, by understanding variability and making sorption capacity renewable, SP could provide, with shorter retention times, a space-efficient, long-term removal strategy. This multi-study research program developed the urban wetland filter (UWF), a concept intended to overcome the unique limitations of high land-value areas to natural treatment strategies and provide a low-cost, easily implemented BMP to meet P management goals while harvesting sequestered P for use as a fertilizer. Experimental factors included substrate and influent properties pertinent to understanding performance variation and optimizing microbial iron (Fe) reduction for rejuvenation of sorption capacity. Regarding performance, modeling identified major sources of variability including, by order of importance, magnitude of a solution/substrate concentration gradient, length of the "antecedent dry period" between loadings, and pH. Field-scale results confirmed this multifactor dependence of P-removal while also supporting the inclusion of cast-iron filings in substrate to improve P removal. Regarding rejuvenation, results indicated that microbial Fe reduction is capable of releasing previously sequestered P from substrates. A sufficient carbon source was necessary, but microbial inoculation was not necessary to facilitate Fe reduction, which released most of the previously sequestered P, albeit more slowly than P sequestration. Field-scale results indicated that Fe reduction might occur faster under field conditions, possibly due to humic acids, and that inclusion of cast-iron filings enabled additional P removal after rejuvenation by providing a conservative source of Fe for the creation of new sorption sites; however, cast-iron filings may also limit the release of P during rejuvenation. / Ph. D.

Contaminated stormwater discharge is a major concern in the United States due to a steady increase of harmful pollutants entering fresh water sources. The many congressional mandates that require local governments to reduce the impact of storm water discharge on the natural ecology have greatly increased the need for economically and environmentally viable solutions to pollution reduction. One such solution is that of constructed wetlands. Previous research conducted at the Sustainable Bio-products Department at Mississippi State University demonstrated the feasibility of kenaf fiber and wood shavings to remove toxins and crude oil from the bio-oil process water. This study proposes to amend contaminated storm water runoff from a biomass to bio-oil conversion facility through a simulated constructed wetland. The constructed wetlands were contaminated with varying dilution levels of bio-oil process water in a series of six phases. It was hypothesized that the contaminated rainwater can be remediated by constructed wetlands and safely released back into the native waterways. This study concluded that there was a significant decrease in biological oxygen demand (BOD) and micro-toxicity over a ten day cycle within the constructed wetlands for the lower levels of contaminated stormwater. A comparative screen of the bacterial community within the wetlands during the contamination process showed a similar trend in species richness and composition for the first three Phases of contamination. There was a shift in richness and diversity for the final three Phases of contamination after ten days within the constructed wetlands. The constructed wetlands were successful at lowering BOD and toxicity levels and achieving permissible pH levels when the concentration of contaminated stormwater was less than or equal to 400x dilution. Much of the BOD reduction was due to volatilization of the contaminated wastewater. When the concentration of contaminated water exceeded 300x dilution, the constructed wetland were only successful at achieving permissible pH discharge levels. Better results may be achievable with longer residence time in the wetlands.

A 0.2-hectare wetland was constructed in the floodplain of Opequon Creek in Northern Virginia as a best management practice (BMP) for stormwater management. The research goals were to 1) determine if wetland hydrology existed and quantify the role of groundwater exchange in the constructed wetland (CW) water budget, 2) estimate wetland hydraulic characteristics during overbank flows, and 3) quantify the event-scale nutrient assimilative capacity of the constructed wetland. CW water table elevations and hydraulic gradients were measured through an array of nested piezometers. During controlled flooding events, stream water was pumped from the creek and amended with nutrients and a conservative tracer in two seasons to determine hydraulic characteristics and nutrient reduction. Samples were collected at the inlet, outlet structure, and at three locations along three transects along the wetland flowpath. Water table elevation monitoring demonstrated that wetland hydrology existed on the site. The mean residence time of the wetland was found to be 100 min for flow-rates of 4.25-5.1 m3/min. Residence time distributions of the high and low marsh features identified a considerable degree of flow dispersion. Manning's n varied between macrotopographic features and was significantly higher in the spring event as compared to the fall event, likely due to the presence of rigid-stem vegetation. Average wetland n was 0.62. Total suspended solid concentrations decreased with increasing residence time during both experiments. Mass reduction of pollutants were 73% total suspended solids (TSS), 54% ammonia-nitrogen (NH3-N), 16% nitrate-N (NO3-N), 16% total nitrogen (TN), 23% orthophosphate-phosphorus (PO4-P), and 37% total P (TP) in the fall, and 69% TSS, 58% NH3-N, 7% NO3-N, 22% TN, 8% PO4-P, and 25% TP in the spring. Linear regression of mass flux over the event hydrograph was used to determine pollutant removal rates between the wetland inlet and outlet. Pollutant removal rates were determined through linear regression of mass flux and were higher in the spring event than in the fall. Dissolved nitrogen species were more rapidly removed than dissolved phosphorus. TSS, TP, and TN removal were greater and faster than dissolved nutrient species, suggesting that physical settling was the dominant removal mechanism for stormwater pollutants. / Ph. D.

Constructed wetlands are considered an inefficient technology for long-term phosphorus (P) removal. The P retention effectiveness of subsurface wetlands can be improved by using appropriate substrates. The objectives of this study were to: (i) use sorption isotherms to estimate the P sorption capacity of the two materials, masonry sand and light weight expanded shale; (ii) describe dissolved P removal in small (2.7 m3) subsurface flow wetlands; (iii) quantify the forms of P retained by the substrates in the pilot cells; and (iv) use resulting data to assess the technical and economic feasibility of the most promising system to remove P. The P sorption capacity of masonry sand and expanded shale, as determined with Langmuir isotherms, was 60 mg/kg and 971 mg/kg respectively. In the pilot cells receiving secondarily treated wastewater, cells containing expanded shale retained a greater proportion of the incoming P (50.8 percent) than cells containing masonry sand (14.5 percent). After a year of operation, samples were analyzed for total P (TP) and total inorganic P (TIP). Subsamples were fractionated into labile-P, Fe+Al-bound P, humic-P, Ca+Mg-bound P, and residual-P. Means and standard deviations of TP retained by the expanded shale and masonry sand were 349 + 169 and 11.9 + 18.6 mg/kg respectively. The largest forms of P retained by the expanded shale pilot cells were Fe+Al- bound P (108 mg/kg), followed by labile-P (46.7 mg/kg) and humic-P (39.8). Increases in the P forms of masonry sand were greatest in labile-P (7.5 mg/kg). The cost of an expanded shale wetland is within the range of costs conventional technologies for P removal. Accurate cost comparisons are dependent upon expansion capacity of the system under consideration. Materials with a high P sorption capacity also have potential for enhancing P removal in other constructed wetland applications such as stormwater wetlands and wetlands for treating agricultural runoff.

Nutrient availability, water depth, competition, and soil management effects on cattail (Typha latifolia) growth in wetland systems were examined. Soluble reactive phosphorous (SRP), nitrate-nitrogen (NO3-N), and ammonia-nitrogen (NH3-N) removals were tested at a constructed wetland receiving municipal wastewater effluent. Over all, no significant differences in nutrients occurred between diverse planted and cattail areas. T. latifolia seeds, under the canopy of Eleochoris macrostachya, had low seed germination. Established stands of emergent vegetation can prevent cattail colonization and spread. Germination of T. latifolia at various water depths was tested, and depth impacts on cattail seedling growth and survival were ascertained using various moist soil management techniques in three ponds. Water levels at 0cm and >40cm can adversely impact cattail establishment.

Student test scores related to mathematical word problems have been declining in a rural school district in western Louisiana. Word problems constitute a major component of the Algebra 1 End of Course examination, which students must be able to pass to graduate. Mathematics teachers have struggled to find appropriate strategies to teach students to answer constructed response questions (CRQs) effectively. The purpose of this study was to investigate the perceptions of math teachers about effective teaching strategies for improving student performance on CRQs. Guided by Piaget's constructivist theory, which is characterized by an emphasis on learner control of the learning process through active engagement and activation of prior knowledge, this study investigated teachers' perceptions and practices in relation to teaching the skills needed for CRQs. The research questions focused on math teachers' perceptions of current teaching practices, instructional effectiveness, and professional development needs. A case study design was used to capture the insights of 8 participants through semistructured interviews and observations. Emergent themes were identified from the data through a code-recode approach, and findings were developed and validated through triangulation and member checking. The key results were that math teachers expressed a need to collaborate with their colleagues to develop effective strategies that would incorporate literacy and hands-on learning. A project was designed to engage teachers in collaboration and planning to prepare students to think critically and problem solve. This study may promote positive social change by providing teachers with the tools necessary to improve students' thinking skills, problem-solving skills, and learning strategies.

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