Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains vi, 131 p. : ill. (some col.), col. map. Vita. Includes abstract. Includes bibliographical references (p. 69-74).

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Acid Mine Drainage (AMD) is characterized by high metal concentrations and an extremely low pH, primarily generated by the microbial oxidation of iron sulfides from mine tailings. Research on the microbial AMD community has largely focused on Bacteria, while little information is known about the Archaeal and Eukaryote members or the seasonal patterns within the communities. Here I examined the Bacterial, Archaeal, and eukaryotic AMD seasonal microbial community, using direct sequencing techniques on AMD samples from the Copper Cliff Tailings AMD site in Sudbury, Ontario, Canada. I found large variation in the community profile and species composition between sampling times of both the Bacterial and Eukaryote communities, suggesting a dynamic community, both between and within seasons. Bacterial diversity was highest during the winter, with Acidithiobacillus dominating, while during the summer, Acidiphilium was the dominant genus. The winter Eukaryote community was dominated by classes of algae and fungi, while the majority of summer sequencing could not be classified to the class level. Few reads were obtained for the Archaeal domain, with low and similar biodiversity between seasons. Overall, the AMD community variation and abundance were found to largely correlate with drainage water and seasonal temperature.

The oil production from well fractured carbonate reservoirs is a considerable part of the total oil production in the world. The petroleum resource base in naturally fractured reservoirs is estimated to be in the range of billions of barrels in the U.S and in addition, a multibillion- barrel international oil resource base exists in naturally fractured reservoirs. Gravity drainage is important in some of oil recovery processes, either acting as the driving force in processes using horizontal wells or altering the displacement patterns during water-flooding, chemical flooding, CO2 flooding and other EOR methods. The gravity drainage process has a major effect on oil recovery from oil reservoirs. Gravity drainage driven oil production in naturally fractured and other complex reservoirs falls into two regimes: the balk flow regime and the film flow regime. Oil recovery by gravity drainage in a fractured reservoir strongly depends on the capillary height of the porous medium. Capillarity and gravity forces are usually the major driving forces in fractured reservoirs. This PhD thesis consists of two main parts namely: 1) Experimental works on gravity drainage, and 2) Modeling and simulation of the gravity drainage processes using COMSOL® software. An appropriate design of experiment (DOE) method was selected to find the most important parameters contributing in gravity drainage and then conduct the experiments in a useful as well as economic manner. A two-dimensional experimental setup was employed to investigate free fall gravity drainage (FFGD) and controlled gravity drainage (CGD) using unconsolidated glass beads fractured porous media having various fractures configurations. Flow visualization measurements were carried out. Following the flow visualization experiments, parametric sensitivity analysis was performed considering the effects of different system parameters such as fracture aperture, matrix height, permeability, and fluid properties on the dependent variables including drainage rate, critical pumping rate, maximum drainage rate, recovery factor and so on. These experiments enabled us to capture some aspects of the recovery mechanism and the flow communication between matrix block and fracture during gravity drainage. After analyzing the experimental data for the FFGD test runs, it was found that the rate of liquid flowing from matrix to fracture is proportional to the difference of liquid levels in the matrix and in the fracture. In addition, the characteristic rate and the maximum liquid drainage rate from the fractured models were determined for such a stable gravity-dominated process. The experiments showed that the presence of fracture is more influential in lower matrix permeability systems. For a given fracture-matrix system with different initial liquid saturation conditions, it was seen that the production history can be correlated by plotting the fraction of recoverable liquid as a function of time. Furthermore, the recovery factor can be correlated using dimensionless numbers such as the Bond number and the dimensionless time. For the controlled gravity drainage (CGD) test runs conducted, the experimental results indicated that higher pumping rates cause a higher difference between the liquid levels in the fracture and in the matrix, thus the gas breakthrough happens sooner. Moreover, it was found that as long as the porous medium is drained with a constant liquid pumping rate but lower than critical rate, the height difference between the G-L interfaces in matrix and fracture remains constant. In this study, a new concept of “Critical Pumping Rate” (CPR) was defined at which each particular porous medium has recovery factor equal to the recovery factor for higher rates just before gas breakthrough. The difference between liquid levels in fracture and matrix remains unchanged at rates higher than CPR. Known this particular withdrawal rate, there are two main advantages, namely: 1) choosing a pumping rate lower than it to drain the reservoir without getting gas breakthrough; and 2) understanding the physics of pumping behaviour from fractured media and extending the concept to the real cases. In addition, the maximum liquid pumping rate from each physical model was studied and it was found that the rate depends strongly on the storage capacity of the fractures, petrophysical properties of each model as well as physical properties of test fluids. The critical rate, maximum rate, recovery factor at gas breakthrough and difference of gas liquid interface positions in matrix and fracture were correlated by dimensionless numbers such as Bond number, Capillary, and the ratio of permeabilities. Linear regression correlations presented in this study can predict production history and flow behaviour in the fractured porous media for a wide range of dimensionless numbers. The COMSOL® software was used to numerically simulate the gravity drainage processes in the two-dimensional flow experiments for fractured porous media. The parameters of the model were based on theory, as well as on the results of the two-dimensional gravity drainage experiments. The simulation results for the gravity drainage processes compared favourably with the experimental results, as a good match between the numerical solution and the experimental data was found. The simulation model developed provides a basis for further modeling of gravity drainage process in more complicated porous media.

A wastewater treatment and reuse system consisting of a tile drainage system, a constructed treatment wetland (CTW), a reservoir, and an irrigation system was established. The system supplied 780 mm of irrigation water for the 1.8 ha of drained land for the 2008 growing season. A hydraulic tracer study conducted in the CTW supported the use of a length to width ratio of 10:1. During 2008, annual nitrate-nitrogen (NO3--N) and Escherichia coli (E. coli) mass reductions were 67.6 and 63.3%, respectively. Elevated E. coli levels were observed in the reservoir during the warm season. Therefore, water may not be safe for irrigating crops consumed raw. The mean first-order areal uptake rate constants generated for NO3--N and E. coli were 8.0 and 6.4 m y-1, respectively, and are recommended for similar CTWs. A wetland area to drainage area ratio of 4.5% is recommended to achieve ? 70 % mass reduction of NO3--N and E. coli

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Four ponded depressional areas were selected in a cultivated field near Ste-Agnes de Dundee, Quebec. In 1988, land, soil, water and crop parameters were measured under ponding and non-ponding conditions in order to formalate a drainage investigation procedure for ponded depressions. / A sweet corn yield reduction of 39% was measured in depressions compared to ridges; this yield reduction occurred with 3 to 5 year interval of recurrence rainfalls. Loss of yield in depressional areas gave an overall reduction of 5% for the whole field. There was an additional loss in quality from poor uniformity of the corn cobs. The Ste-Agnes corn yield was estimated at 20% of the regional average. There was no significant difference between soil characteristics in depressions and ridges except for hydraulic characteristics such as infiltration and percolation rates as determined with the infiltrometer, and hydraulic conductivity as determined with the auger hole method. / The ponding runoff coefficients (mean PRC = 0.11) measured during the summer of 1988 were similar to the ones (mean PRC = 0.13) calculated using the CN curve method (USDA, SCS). / The low percolation rate of the subplow layer was found to be the main constraint to the subsurface drainage of the ponded depressions. / Soil survey and ponding study results were used to formulate a drainage investigation procedure for ponded depressional areas in the St. Lawrence Lowlands.

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Numerous streams on the West Coast drain catchments impacted by active or abandoned coal mining areas. Acid mine drainage (AMD) from coal mining can have significant negative effects on stream communities. Changing environmental ethics and regulations mean that mining companies are now encouraged to treat acid mine drainage to enable streams communities to recover. However, remediation efforts have not always been ecologically successful, and mining companies are seeking methods to enhance macroinvertebrate community recovery. Initially, I conducted an extensive survey of 45 streams draining the Stockton Plateau, which is the site of the largest opencast coal mine in New Zealand. I assessed physical and chemical conditions at each site as well as sampling benthic communities. This spatial survey showed streams impacted by acid mine drainage were comprised of chironomids and AMD-tolerant caddisflies such as Psilochorema and stoneflies such as Spaniocercoides. Un-impacted streams typically had a pH of ~5 and were dominated by mayflies (Deleatidium or Zephlebia). Analysis revealed that stream location within the landscape also had a significant influence on macroinvertebrate community composition. Another aspect of stream recovery is the ability of species to recolonise a stream. Therefore, I investigated the flight direction of adult aquatic insects in order to determine longitudinal and lateral flight preferences. No significant differences in flight direction were observed. I also investigated the influence of riparian habitat on lateral dispersal and found that a number of patterns were evident. Scrub vegetation supported higher densities of adult aquatic insects dispersing further from the stream, in contrast to the rapid decline in open bedrock and forest. Furthermore, a comparison between downstream drift and aerial flight showed significantly more individuals where drifting downstream, and this method is liable to provide rapid recolonisation of macroinvertebrates within connected stream networks. At the local scale, organic matter (comprising leaves bags and timber) and artificial moss cover were added to six streams to determine if organic matter and habitat availability would improve macroinvertebrate communities in manipulated streams. A series of floods during the experiment reduced taxonomic richness and density in manipulated streams. Overall, this study has shown that after AMD has been treated, the geographic position of streams within the landscape and lateral dispersal barriers may prevent streams being rapidly re-colonised. Therefore, to promote rapid re-colonisation of macroinvertebrates, stream remediation projects should be targeted at streams that either have un-impacted headwaters or tributaries. This will allow macroinvertebrates to drift in and re-colonise faster. In my experiment I did not find that organic matter significantly enhanced the macroinvertebrate community, but moss additions did provide additional habitat for macroinvertebrates. These results highlight the importance that disturbance events can have on remediation projects.