Current reclamation research following surface mining in the Appalachian coal region seeks to measure carbon (C) and nutrient accumulation and retention under forest vegetation to better understand the role of reforestation in the re-establishment of these ecosystem services. This study capitalized on the Controlled Overburden Placement Experiment (COPE), a 29-year-old reclamation research installation in southwestern Virginia, to estimate long-term mine soil C sequestration potentials and nutrient capitals after different reclamation strategies. The COPE includes two studies, a rock mix study (RM) comparing topsoil substitutes created from different ratios of local overburden [pure sandstone (SS), pure siltstone (SiS), 2:1 SS to SiS, 1:1 SS to SiS, and 1:2 SS to SiS], and a surface amendment study (SA) comparing organic amendments [control (CON), natural topsoil (TS), sawdust (SD), and 22 Mg ha-1 (22B), 56 Mg ha-1 (56B), 112 Mg ha-1 (112B) and 224 Mg ha-1 (224B) of biosolids] on a common 2:1 SS to SiS topsoil substitute. In the RM, overburden selection significantly affected soil nitrogen (N) and C concentrations as well as many other soil chemical [e.g., available phosphorus (P), pH, and other macro- and micronutrients) and physical (e.g., sand, silt and clay contents) properties.    C sequestration rates were also significantly different and ranged from 0.13 to 0.47 Mg C ha-1 yr-1. Many of the differences demonstrated relationships with the mineral make-up of the RM treatment. The SA mine soils also differed significantly in many properties after 29 years, including N, C, and many other nutrient concentrations and contents. C sequestration rates were also significantly different with the SD and 224B treatments having negative sequestration rates, and the remaining treatments ranging from 0.23 to 0.80 Mg C ha-1 yr-1. Collectively, the results demonstrate that topsoil substitutes and surface amendments show divergent trends in soil C and nutrient dynamics after nearly three decades of development and stress the importance of post- mining reclamation based on available materials and reclamation goals. / Master of Science

This thesis deals with water reclamation and water reuse in the South African water supply context. The overall objective of the study is to assess the potential role and feasibility of reverse osmosis as a water reclamation process. In order to achieve this objective a number of separate desk, laboratory and pilot plant studies were conducted. It was concluded from the first desk study that a significant potential role exists for reverse osmosis in the South African water economy, mainly for the treatment of industrial effluents and, in the longer term, for the reclamation of water from sewage effluents and for the treatment of effluents and recycled water in indirect water reuse situations. A cost analysis showed that reverse osmosis could become economically viable in some water reuse situations in the near future provided that a productive membrane life of about three years can be achieved and that membrane fluxes can be maintained at design rates. These findings indicated the need for a pilot plant study to determine the effects of pretreatment and membrane cleaning on flux levels and rejection. A 50 m³/d pilot plant was designed and operated for a period of about six months from which it was concluded that acceptable flux levels can be maintained in tubular reverse osmosis plants treating well-oxidized activated sludge effluent with and without extensive pretreatment, provided both chemical and physical cleaning methods are employed. The desk study on the rejection of contaminants by reverse osmosis membranes indicated the need for a simple model that can be used to predict the removal of organic compounds of interest in water reclamation applications. It was concluded from a fundamental laboratory study, which included the evaluation of existing membrane models against laboratory data, that the solvophobic theory can be adapted in a simplified form to predict the transport of dissolved organic compounds in relatively non-polar reverse osmosis membranes. Based on reverse osmosis, diffusion, sorption and desorption data a mechanism is, furthermore, proposed for the transport of phenol in different membranes.

Reclaimed roads on the Little Missouri National Grasslands of southwestern North Dakota have not returned to pre-disturbance conditions. Phospholipid fatty acid analysis was performed on soil samples collected from reclaimed roads and adjacent prairie to assess reclamation effects on the microbial community. Additionally, nutrient cycling capacity was measured by four enzyme assays. Ordination analysis of PLFA data identified a distance gradient indicating microbial communities of reclaimed roads were different from the prairie. Specifically, Gram-negative bacteria and arbuscular mycorrhizal fungi are associated with roads; soil organic matter was associated with prairie sites. Soil enzyme activities associated with prairie sites indicate greater nutrient cycling. The soils of reclaimed roads have not accumulated sufficient organic matter to sustain both plant and microbial communities characteristic of the surrounding prairie.

Land management techniques can enhance altered ecosystems on a variety of landscapes. In the Williston Basin of North Dakota, brine ponds created 50 years ago still cause problems today. We applied six treatments to reclaim the A-horizon of brine-affected soil on six legacy brine ponds and monitored soil nutrients until 23 months after treatment. We found that from 0-15 cm, all treatments were significantly better at reducing electrical conductivity than the control. In addition, sodium adsorption ratio was reduced at all depths over time. In Southcentral North Dakota, we monitored the effects of fire and grazing on colonies of western snowberry (Symphoricarpos occidentalis), an invasive woody shrub. Prescribed burning had a significant effect on western snowberry by reducing the number of mature plants and increasing the number of new shoots/m2. By incorporating drone aerial imagery, we helped develop an increasingly useful tool in vegetation monitoring.

Wetland reclamation efforts in the Athabasca Oil Sands Region seek to restore important ecosystem services that were lost consequent of disturbance from oil sands mining development in northern Alberta, Canada. Constructed on the Syncrude Canada Ltd. mineral surface lease, the Sandhill Watershed is the first attempt to engineer a landscape capable of supporting a self-sustaining wetland above a backfilled open-pit mine. In the chapters below, through characterization of porewater chemistry patterns, plant community structure, physical characteristics of soil and nutrient availability the overall performance of the wetland area (the Sandhill Wetland) is evaluated. Further, observations at the reclaimed site are compared to 12 reference wetlands (10 fens and 2 marshes) to evaluate the type of wetland to which the Sandhill Wetland is most analogous. After six growing seasons, although water table position management has occurred annually, the Sandhill Wetland exhibits many attributes similar to those of the natural sites monitored. In terms of porewater chemistry, the dominant anions and cations present in near-surface water (bicarbonate, sulfate, chloride, sodium, calcium, and magnesium) have increased annually since the first growing season. If trends continue, the chemical conditions at the reclamation site could be analogous to saline fens in about 7-8 years based on projections for increasing sodium and chloride concentrations. The Sandhill Wetland currently exhibits porewater chemistry attributes most similar to saline fens and slightly brackish marshes. Total plant cover across the reclaimed wetland was quite high averaging 95% in the sixth growing season. Using multivariate approaches (NMDS), results show that plant community structure across high and intermediate water table position areas are most comparable to marshes, with Typha latifolia and Carex aquatilis exhibiting the highest cover. Across the periphery of the site, where water table position is several centimeters below the soil surface, plant communities are quite dissimilar from the reference sites and dominated by the grass Calamagrostis canadensis. While sodium-tolerant species are present at the site, albeit at low abundance, it is unclear whether long-term exposure to sodium-dominated porewaters currently present at the Sandhill Wetland will affect performance of wetland plants that established under low-sodium conditions. In terms of soil characteristics, clear differences were apparent, namely, for soil bulk density patterns. Bulk density observations across all areas at the Sandhill Wetland were higher than the reference sites and total soil carbon concentrations were also low. These observations were expected, and as the Sandhill Wetland matures, I predict annual production and (or) deposition of plant litter/ roots and increased biological activity will restore near-surface soil properties in the wetland area, thereby increasing TC concentrations and reducing soil compaction. For functional processes, using plant root simulator (PRS) probe ion exchange membranes, results demonstrate nutrient supply across the Sandhill Wetland was most similar to the moderate-rich and saline fens except for sulfur supply, which was considerably elevated. Based on PRS probe and porewater observations, the Sandhill Wetland is not a eutrophic system in the sixth growing season, and supply for most nutrients are within the ranges of natural systems. However, effects from local atmospheric nitrogen deposition (reported up to 12 kg N ha-1 yr-1) could alter structure and function over subsequent growing seasons. Currently, ecosystem health and functionality of the belowground environment appears to be adequately restored at the reclamation site. Lastly, as no officially recognized protocols exist for evaluating performance of recently reclaimed wetlands constructed above open-pit mines, using the Sandhill Wetland as a test site I propose a framework for evaluating reclamation site performance. Although the proposed evaluation protocol does not rely on multivariate techniques, the performance evaluation results support the previous findings (that were based on multivariate analysis) that a marsh-like analogue is the most realistic reclamation outcome for the reclaimed Sandhill Wetland. While the reclamation has been highly successful in terms of creating a wetland that has persisted, future monitoring of water chemistry and plant community structure should continue at the Sandhill Wetland, to capture important successional changes that may occur as the site matures.

No description available.

As oil production increases in Alberta’s Athabasca Oil Sands Region (AOSR), optimization of tailings management processes will be integral to the successful reclamation of tailings-based environments. Syncrude Canada Ltd. has established an innovative dry-storage method for their wastes known as composite tailings (CT) that supports mine closure objectives by providing a base for terrestrial reclamation landscapes. Syncrude’s Sandhill Reclamation Fen is the first instrumented research wetland of its kind to be developed in the AOSR and it overlays a sand-capped composite tailings deposit in a retired open-pit mine site. This stratified sulfur-rich environment is highly anthropogenically altered and consists of three distinct zones: a constructed wetland, a 10m layer of sand, and 40m of CT. As oil sands tailings systems are becoming globally significant sulfur reservoirs due to their size, sulfur content, and diverse microbial communities, understanding the mechanisms behind H2S generation in novel tailings structures will help inform our understanding of sulfur-rich environments. This study is the first to characterize the sulfur biogeochemistry in each zone of the Sandhill Reclamation Fen deposit in an effort to establish the potential for microbial sulfur cycling and explore the mechanisms controlling H2S generation. Porewater ΣH2S(aq) was detected at all depths, increasing with depth from the surface of the wetland (<1.1 μM) and peaking in the sand cap (549 μM). Across all sampling trips, ΣH2S(aq) concentrations were consistently highest in the sand cap, with sampling-associated H2S gas concentrations in the wells reaching 104-180 ppm. Abundance of dissolved sulfate (0.14-6.97 mM) did not correlate to the distribution of ΣH2S, and dissolved organic carbon (21.47-127.72 mg/L) only positively correlated with the observed maxima of ΣH2S in the sand-cap. Identical sodium and chloride distributions in the sand and CT supported the model of upward migration of CT-derived porewater and fines into the sand cap. Functional metabolic enrichments established the ability of endemic microbial communities from all depths of the deposit to oxidize and reduce sulfur. Experimental microcosms demonstrated 1) the dependence of ΣH2S generation on the presence of fine particles; 2) stimulation of endemic microbial sulfur reduction through amendment with labile carbon and 3) increased generation of ΣH2S in the presence of thiosulfate over sulfate. Field and experimental results indicated that the bioaccessibility of recalcitrant organic carbon in the deposit likely controls rates of ΣH2S generation at depth. While the mechanisms relating CT-derived fines to ΣH2S in the sand cap are still unconstrained, the sand layer is clearly a bioreactive mixing-zone supporting optimal conditions for ΣH2S accumulation. These findings inform our understanding of biogeochemical sulfur cycling in novel oil sands reclamation deposits and will advise on-going optimization of tailings-based landscape management practices. / Thesis / Master of Science (MSc)

In this study, phospholipid fatty acids (PLFA) and carbon isotopes were used to characterize the response of in situ microbial communities to a pilot-scale wetland reclamation project in the Alberta oil sands, and to investigate their role in carbon cycling at the reclamation site. The Sandhill Fen reclamation project in the Athabasca oil sands region (Fort McMurray, Alberta, Canada) has created an artificial freshwater fen typical of the boreal forest region in which the oil sands occur. At this site, composite tailings (CT) residue was overlain with a thick sand cap and a freshwater fen constructed on top. Biomass in the peat material of the fen was comparable to that found in natural fens, and a comparison of PLFA profiles in peat, CT from a nearby site, and undisturbed wetlands in the area showed that microbial communities in Sandhill fen were more similar to those in the CT than those in undisturbed wetlands. Bacteria dominated the biomass, including a small percentage of sulphate reducing bacteria that are of particular interest in the reclamation project. Fungi and other eukaryotes were also present. Analyses of radiocarbon in total organic carbon (TOC) and residue from solvent extraction suggest that there was petroleum present in the peat layer of the fen. A small amount of young carbon from the fen surface has been transported into the CT layer in the form of dissolved organic carbon. Radiocarbon also showed that microbes preferentially metabolized more modern carbon within the carbon sources available to them. Biomass was more related to the age of carbon in the samples than to the TOC concentration, with younger carbon in the peat associated with higher PLFA concentration. / Thesis / Master of Science (MSc)

Fresh water, particularly potable water, is a critically important, albeit scarce, resource to human beings. Increasing evidence of polluted fresh water bodies indicate water usage patterns that are detrimental to the scarce reserves of fresh water on a regional and global level. It may be said however, that, that the current problems of water wastage and abuse are not merely the results of the technology used but more so of the erroneous perceptions that have guided its development. Therefore it is crucial to not only adopt different technology to solve current water management problems but more important to create a new holistic paradigm of water management that provides the framework for ecologically sustainable technology. The thesis on a circular model of urban hydrology is an attempt in this direction. The thesis is based on the need to develop a sustainable model of urban hydrology. It is a descriptive model that combines existing technologies in a manner that would make them relevant to present and future cities and is applied on a conceptual level to study the implications that this new model could have on the urban landscape. By exploring the concepts of waste water reclamation and re-use, and storm water management that is connected to the city's water supplies, the circular model attempts to attempts to reduce the affects of urbanization and urban water usage on external natural systems while establishing ecologically benign links with the regional and global environments. The use of biological systems for wastewater reclamation has different implications to the urban physical environment in terms of its landuse patterns, open space systems, human activities and aesthetics, than a conventional centralized system of water supply and disposal. The thesis discusses those implications that are particularly relevant to those involved in the planning and design of cities and speculates on an urban environment that might be different from an existing modern city. / Master of Landscape Architecture

No description available.