Master of Science, The Ohio State University, 2016, Food, Agricultural and Biological Engineering

Anaerobic digestion (AD) is a waste-to-energy technology in which microorganisms convert organic materials into two main products: a methane-rich biogas that can be used as a renewable energy source, and a nutrient-rich liquid effluent that is an effective organic fertilizer. The primary method for effluent disposal is land application to crops. However, AD effluent typically has a high phosphorus content and a lower than optimal N:P ratio for crops. Land application often supplies excess phosphorus, contributing to eutrophication and limiting application rates in areas with strict environmental regulations. The inability to dispose of AD effluent has emerged as a major barrier to the advancement of Ohio's waste-to-energy industry. A potential solution is to remove and recover phosphorus from AD effluent prior to land application to improve disposability and protect water quality. Following solid-liquid separation, soluble phosphorus in the liquid stream (i.e. AD effluent filtrate) can be removed using calcium precipitation. The insoluble calcium phosphates that form during calcium treatment can be recovered and potentially reused in agriculture. Although this method is effective, calcium treatment is often prohibitively costly, in part because large quantities of precipitant are required for effective treatment. The objective of this study was to investigate the use of flue gas desulfurization (FGD) gypsum as a novel, low-cost calcium source for the removal and recovery of phosphorus from AD effluent filtrate. FGD gypsum is high purity CaSO4·2H2O that is produced in abundance as a waste product at coal power plants during the scrubbing of SO2 from coal combustion off-gases. FGD gypsum consistently contains very low heavy metal content and is widely used as a soil amendment in agriculture. In contrast to other low-cost materials that have been studied for phosphorus removal, FGD gypsum is widely available and has high potential for reuse after treatment. FGD gyp (open full item for complete abstract)

Committee: Yebo Li (Advisor); Jay Martin (Committee Member); Warren Dick (Committee Member) Subjects: Agricultural Engineering; Alternative Energy; Environmental Engineering; Water Resource Management

Master of Science, The Ohio State University, 2012, Food, Agricultural and Biological Engineering

Municipal and industrial by-products are often treated as waste and are disposed in landfills despite containing nutrients that can be used for beneficial purposes. This study examines the impact that two waste products, Flue Gas Desulfurization (FGD) gypsum and municipal biosolids, have on the growth and biofeedstock quality of a promising bioenergy crop, Miscanthus x giganteus when grown on marginal lands. This study also evaluated any improvements in soil quality of marginal lands that occurred from the application of these two soil amendments. Biosolids significantly increased Miscanthus biomass height, and density on marginal lands, and resulted in dry biomass yields that were three times higher than in the other treatments. FGD gypsum had no impact on Miscanthus growth, but it is possible that a longer study period is needed to see significant differences in yield. Nutrient and heavy metal content of the Miscanthus feedstock were measured to determine if there were any significant deficiencies or toxicities in the feedstock from biosolids and FGD gypsum application onto the soil. The results indicated that the nutrient and metal content of feedstock was not affected by the application of these soil amendments. There were no significant differences in lignocellulosic composition of plants due to biosolids or FGD gypsum application. Pretreatment method had a much greater impact on the recovery of fermentable sugars than the use of soil amendments. Acid hydrolysis was used to determine theoretical sugar recovery from Miscanthus feedstock. This theoretical data was used to evaluate a method that is adaptable to an industrial scale for recovery of fermentable sugars from Miscanthus that utilized microwave pre-treatment and enzyme saccharification. Several different catalyst and temperature combinations were tested during pre-treatment; it was determined that microwave pretreatment and enzyme hydrolysis can reach a maximum recovery rate of 65.2 g/100 g dry bioma (open full item for complete abstract)

Committee: Frederick Michel Ph.D., P.E. (Advisor); Randall Reeder P.E. (Committee Member); Rafiq Islam Ph.D. (Committee Member) Subjects: Agricultural Engineering; Energy; Engineering; Natural Resource Management; Soil Sciences

Doctor of Philosophy, The Ohio State University, 2010, Soil Science

In Ohio, approximately 55% of agricultural land needs drainage to overcome occasional water ponding, reduce soil erosion, improve fields to support farm equipment and reduce crop yield variability. In recent years, many Ohio farmers converted to non-tillage systems without understanding the system constraints especially on poorly drained soils. Due to Ohio being a major coal-burning state for electricity production, enormous amounts of coal combustion by-products such as gypsum are readily available for agricultural use. Gypsum is a source of calcium which may improve the physical properties of the soil by promoting soil aggregation, increasing water surface infiltration rates and movement into and through the soil profile. Several studies in the Midwest have focused on the effect of gypsum controlling surface structure, crusting, sealing and erosion. However few studies have analyzed the structural and hydrologic effects of gypsum on the whole profile of non-sodic soils, especially in subsurface horizons.For that reason, undisturbed soil columns from Brookston loam and Celina silt loam soils with different gypsum application regimes were collected to determine the effect of gypsum on physical-chemical soil properties and hydrology of these two non-sodic soils with contrasting drainage from no-till fields. Higher exchangeable calcium and Ca:Mg ratios were found on both gypsum treated soils. Soil turbidity and light transmittance studies showed a positive effect with respect to gypsum application rate. Clearer suspensions and higher light transmittance were found under long-term gypsum. However, there was no consistent response for gypsum application regimes in both soils for water stable aggregates, water stable aggregates by aggregate size and mean weight diameter on the whole soil profile. Positive gypsum effects on both Brookston treated soils were observed. Greater water stable aggregates were found for > 4mm aggregates in the top 60 cm of short-term gypsum trea (open full item for complete abstract)

Committee: Brian Slater K (Advisor); Warren Dick A (Committee Member); Edward McCoy L (Committee Member); David Barker J (Committee Member) Subjects: Soil Sciences

Doctor of Philosophy (PhD), Ohio University, 2024, Biological Sciences (Arts and Sciences)

Plant communities that occur on restrictive soils are characterized by stressful soil conditions and isolated patches of habitat, both of which have important consequences for the ecology and evolution of the species that occur on them. Despite their restrictive nature, edaphic communities contain high biodiversity, comprising a unique assemblage of plants, many of which are rare. Edaphic communities contain numerous, distantly related species that evolved under similar stressful conditions, but we still do not understand how the evolutionary process of edaphic specialization and speciation unfolds or the myriad of ecological and evolutionary consequences of occurring on restrictive soils. I examined species that occur on and off gypsum-edaphic communities to answer four questions, each as its own chapter: (Chapter 2) What fitness consequences do plants that occur on restrictive soils experience, (Chapter 3) how do diversification rates change for clades where gypsum endemism occur, (Chapter 4) how have dispersal syndromes and dispersion changed in edaphic communities because of their restrictive, fragmented substrate, and (Chapter 5) has selection favor limited dispersal in gypsum endemics? To answer those questions, I compared plant communities on gypsum outcrops (which contained both endemics and tolerators [= plants that grow on and off gypsum]) with surrounding, non-gypsum communities, and analysed selection and diversification rates of various gypsum associated clades. To determine the fitness consequences of inhabiting gypsum, I measured fitness for gypsum tolerating species across an edaphic gradient of gypsum to non-gypsum soils. I found negative and neutral fitness effects for species growing on gypsum soils. Various physical and chemical properties control fitness of tolerator species, but no common soil property was identified between the species that explained fitness changes on gypsum soil. To answer my second question, I gathered pre-constructed clado (open full item for complete abstract)

Committee: John Schenk (Advisor); James Dyer (Committee Member); Rebecca Snell (Committee Member); Jared DeForest (Committee Member) Subjects: Biology; Ecology; Plant Biology

Bachelor of Science (BS), Ohio University, 2023, Environmental and Plant Biology

Gypsum soils have unique chemical properties that restrict edaphic communities of plants to them. Soils containing high levels of gypsum occur in patchy outcrops that form island chains throughout the southwestern deserts in North America. Island biogeography theory suggests that island communities should have higher species turnover than mainland communities due to isolation limiting dispersal events that would otherwise homogenize them. We tested the hypothesis that because of their discontinuous, island distributions, gypsum outcrops would have greater differences in species composition (beta diversity) than comparable populations from the surrounding non-gypsum floral communities. This result would demonstrate that the community assemblage of gypsum is governed by the same processes that lead to high species turnover in insular systems. We analyzed species presence/absence data collected from 148 gypsum sites and 148 paired nearby non-gypsum sites and compared the estimated beta diversity values between them using a paired t-test. We then ran a linear regression to determine whether beta diversity is influenced by the distance between sites. Beta diversity was not significantly different between gypsum outcrops and the surrounding non-gypsum communities. Both soil types had high beta diversity indicating low levels of similarity between sites whether the community was on or off gypsum. As expected, distance between the sites significantly influenced the beta diversity among non-gypsum sites and the beta diversity among gypsum outcrops. As distance increased, the differences in species composition increased. Looking at the coefficient of determination, the results show that the variance in beta diversity among the non-gypsum communities is more explained by distance than the variance in beta diversity among the gypsum Finding that both the gypsum outcrops and the non-gypsum sites are equal in dissimilarity from others shows that gypsum outcrops are not as physica (open full item for complete abstract)

Committee: John Schenk (Advisor); Rebecca Snell (Advisor) Subjects: Botany; Ecology; Plant Biology

Master of Science, The Ohio State University, 2023, Aerospace Engineering

In this thesis there are two main studies. The first is an assessment of the role of mineral composition for Air Force Research Laboratory Test Dust (AFRL) for deposition in a realistic gas turbine engine environment. The second is an attempt to recreate Arizona Road Dust (ARD) synthetically by analyzing the chemical components of the natural dust and blending synthetic minerals together to match it. In the first study, experiments were performed on an effusion cooling test article with a coolant flow temperature of 894K and surface temperature of 1144K. Aerosolized dust with a 0-10 µm particle size distribution was delivered to the test article. The mineral recipe of AFRL was altered such that the presence of each of the five components ranged from 0% to 100%. For each of these AFRL recipe experiments several results were reported including capture efficiency, hole capture efficiency, mass flow reduction per gram, and normalized deposit height. Results are compared to a previous study of the inter-mineral synergies in an impingement cooling jet at the same temperature conditions. Despite differences in experimental facility flow geometry, overall agreement was found between the trends in deposition behavior of the dust blends. The strong deposition effects that were observed were shown to be related to adhesion forces of particles, mechanical properties, and chemical properties of the dust minerals. In the second study, X-Ray Diffraction (XRD) was performed on ARD to identify minerals present in a naturally sourced dust blend. Pure minerals were mixed in quantities that matched the XRD spectrum of ARD, and oxide content of this synthetic dust blend was shown to match the ISO standard (12103-1) to which ARD conforms. Particle size distribution was also matched to ARD (0-15 µm). Experiments were then conducted in four deposition facilities, one of which was representative of turbine hot section conditions (1500-1625K) and two were representative of internal coola (open full item for complete abstract)

Committee: Datta Gaitonde (Committee Member); Jeffrey Bons (Advisor) Subjects: Aerospace Engineering

Doctor of Philosophy, The Ohio State University, 2022, Horticulture and Crop Science

Many Midwestern organic farmers in their focus on improving soil quality for crop production attempt to balance their soil's calcium (Ca) and magnesium (Mg) saturation levels by applying calcium-rich amendments. For most soils, this practice based on the base cation saturation ratio (BCSR) hypothesis, requires repeated applications of calcitic limestone and or gypsum to increase Ca to approximately 65% of a soil's saturation capacity and reduce Mg saturation to less than 20%. Expected and claimed benefits of this practice of soil balancing include improved soil structure, decreases in weed pressure, and increases in crop yield. We applied various Ca and Mg rich minerals in a corn-soybean-small grain rotation in two Ohio soils over several years. Our treatments were designed to contrast the effects of different Ca to Mg ratios on the weed community and on soil properties. Our research is the first to provide evidence that Ca:Mg ratios in the soil can reduce density of weed seeds found in the soil. At the silt loam soil, broadleaf and grass seedbank densities were on average about 25% and 40% lower after the second year of gypsum applications, respectively, across crops. Weed emergence for the same soil showed a similar response. At the clay loam soil, grass seedbank densities were on average about 40% higher after the third year of epsom application across crops. Our experimental design enabled us to also investigate the claim of soil balancing proponents and farmers that the increases in crop yield they experienced were due to higher Ca:Mg ratios rather than pH correction. We examined crop yield in response to both pH and Ca and Mg saturation levels over 6 years and concluded that balancing the soil Ca and Mg levels did not impact corn or soybean yields but managing soil acidity did. Our results confirm that correcting excess acidity remains the fundamental reason to apply limestone as a tool to improve crop yields. Previously reported research from our project had (open full item for complete abstract)

Committee: Douglas Doohan (Advisor); Christine Sprunger (Committee Member); John Cardina (Committee Member); Steve Culman (Committee Member) Subjects: Agriculture; Agronomy; Soil Sciences

Master of Science, The Ohio State University, 2019, Horticulture and Crop Science

As of 2016, atmospheric sulfur (S) levels in the Midwest have been reduced by 84% compared to recorded maximums. This reduction in atmospheric S has contributed to a deficiency of sulfur in approximately 70% of cultivated soils in the Midwest region. Gypsum, a high calcium (Ca) and S amendment, is a common input used to correct sulfur deficiency. Gypsum not only provides readily available sulfur, but is also believed to improve soil structure, enhancing soil health and, consequently, yield. However, evidence for initial and consistent improvements in soil properties and crop yield have often been lacking. Our objectives were to document short-term effects of gypsum on (1) Ca and S concentrations in soils and plant tissues, (2) yield of corn, forage and oats, (3) soil physical properties (i.e. resistance to penetrometer and water infiltration) and (4) biological properties (i.e. active and mineralizable carbon (C) and organic nitrogen (N)). Fourteen experiments were conducted in five Ohio counties in 2017 and 2018 involving surface application of 2.24 Mg ha-1 of pelletized gypsum at corn and oat planting and within a week of the first alfalfa cutting. Yields were measured, and crop tissues and soils were analyzed for nutrient content. While gypsum did increase S concentrations (P ≤ 0.05) in soil and plant tissues, the percentage of soil exchange sites occupied by Ca ions (Ca saturation) increased in only two of the 14 experiments. No significant increases were observed in soil organic N and soil mineralizable C. Resistance to penetration was significantly lower in gypsum plots in two of the experiments. These results indicate that gypsum can ameliorate sulfur deficiency in the first year of application, but initial detectable effects on soil quality parameters are less likely to occur.

Committee: Douglas Doohan (Advisor); Steve Culman (Committee Member); Warren Dick (Committee Member) Subjects: Agriculture; Agronomy

Master of Science, The Ohio State University, 2018, Horticulture and Crop Science

In Ohio, many organic farmers use the term `balancing' to express the rationale of using a wide variety of soil amendments to improve soil quality and plant health. Soil balancing or the base cation saturation ratio (BCSR) approach is a method first proposed more than 100 years ago that aims to achieve the `ideal soil'. William Albrecht in the 1970's concluded that if saturation of the major exchangeable cations is 65-85% for Ca, 6-12% for Mg, and 2-5% for K, plant nutrition will be balanced. Research conducted by Zwickle et al. (2011) indicated that many organic farmers believe balanced soils produce higher quality crops and have diminished weed infestations compared to unbalanced soils. For many farmers, soil balancing includes using amendments thought to enhance soil biology and increase the soil's capacity to store and release minerals needed by plants. Combined mineral and these organic/bio-active soil products can be very costly, as much as US $1000-1250/ha in the first year. While farmers believe they are benefiting from these expenditures, there is no objective evidence to confirm their belief. I conducted on-farm studies at six locations in Northeast Ohio, with the overall goal of determining the effect of gypsum, with or without “biological stimulants”, on the soil microbial community, crop quality, weed populations, and soil chemical characteristics. Soil seed bank and soil health/biological properties were measured, including soil respiration, active carbon, protein content, microbial biomass, and complete mineral analysis. Crop foliage for nutrient analysis, and crop quality was determined after harvest. Differences in final soil nutrient levels, base saturation, crop and weed community effects were influenced more by the farm than by the treatments applied. After two years, soil sulfur levels were significantly higher in plots amended with gypsum. Failure to detect treatment response by other mineral amendments suggests the relatively narrow difference (open full item for complete abstract)

Committee: Douglas Doohan (Advisor); Warren DIck (Committee Member); Kleinhenz Matthew (Committee Member); Steve Culman (Committee Member) Subjects: Agriculture; Horticulture; Soil Sciences

PhD, University of Cincinnati, 2016, Engineering and Applied Science: Environmental Engineering

The feasibility of the use of flue gas desulfurization gypsum (FGDG) in beneficial applications was evaluated in this study. Release of toxic elements, which is the main environmental concern of the use of FGDG was evaluated under different environmental conditions. Modern and traditional EPA leaching protocols were used to evaluate the release of constituent of concern (COCs) at different pH and liquid-solid ratios. The leaching of COCs from FGDG and FGDG amended soil was tested using the aforementioned leaching protocols. The leaching of COCs was negligible from the FGDG and FGDG-amended soil, signifying its land application would not be an environmental concern. Natural gypsum (MG) is being used for agricultural purposes as a fertilizer and a structural amendment. As both MG and FGDG are chemically and physically similar, the MG is being replaced by FGDG in many applications. Despite the main similarities in chemistry, there could be some differences between the natural and synthetic gypsums in their mineralogy, trace element content and chemical speciation. The present study compared the chemistry, mineralogy and chemical association of elements in MG and FGDG. The effect of the two types of gypsums on soil chemistry when they used as soil amendments was also evaluated. Two batch leaching protocols were used to measure the release of COCs at different pH and LS ratios. The data revealed no significant difference in element leaching from the two types of gypsums and amended soils. The likelihood of FGDG to remove Pb in aqueous phase was studied using Pb spiked water. The effect of sorbent loading, sorbate concentration and system pH on Pb removal by FGDG was evaluated. The solid residues at each pH were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The presence of SO42-, CO32- and OH- in FGDG enables the formation of different Pb precipitates such as anglesite, larnakite (pH 2), leadhillite, cerussite (open full item for complete abstract)

Committee: Dionysios Dionysiou Ph.D. (Committee Chair); Souhail R. Al-Abed Ph.D. (Committee Member); Sivaraman Balachandran Ph.D. (Committee Member); Margaret Kupferle Ph.D. P.E. (Committee Member) Subjects: Environmental Engineering

Doctor of Philosophy, The Ohio State University, 2015, Environment and Natural Resources

Gypsum is a source of calcium and sulfur that improves the physical and chemical properties of the soil. With the benefits associated with gypsum use and the increased availability of synthetic gypsum, its application to soil in Ohio and the Midwest is increasing. Several studies have focused on the effect of gypsum on soil properties. However, little is known about how gypsum affects C stocks in soils. In this study, in addition to gypsum, we also treated the soil with glucose to create a high level of CO2 in the soil profile, and contrasted that with the more slowly released C from plant residues. The overall goal of this dissertation research was to evaluate the effect of plant residues, glucose and gypsum on the growth and nutrient uptake of ryegrass, chemical properties (including total and inorganic C stock) and physical properties of two contrasting soils in Ohio (Wooster silt loam and Hoytville clay loam). Specific objectives of this research were to quantify the effect of (1) gypsum and plant residues on greenhouse gas emissions, (2) gypsum and C amendments on quality of leachate water, (3) gypsum and C amendments addition on C fractions in soils, (4) gypsum, plant residues and glucose addition on soil fertility, growth and nutrients concentrations of ryegrass and (5) gypsum, glucose and plant residues on selected soil physical properties and aggregate-associated C and N. Emissions of greenhouse gases were significantly less from the silt loam soil as compared to the clay loam soil. Gypsum reduced the CO2 emissions from only the Hoytville soil as compared to the untreated control. Addition of gypsum resulted in significant increases in Ca, and S concentrations in leachates as compared to control for both soils, and decreases in P and Fe concentrations significantly in the Hoytville soil only. Also, no significant differences were observed between the low gypsum rate (8.9 Mg ha-1) and the high gypsum rate (26.9 Mg ha-1) on reduction in P concentrations in l (open full item for complete abstract)

Committee: Warren Dick Dr. (Advisor); Rattan Lal Dr. (Committee Member); Brian Slater Dr. (Committee Member); Frederick Michel Dr. (Committee Member) Subjects: Agriculture; Environmental Management; Natural Resource Management; Soil Sciences

Master of Science, The Ohio State University, 2015, Horticulture and Crop Science

From 2000 to 2013 soybean [Glycine max (L.) Merr] grain commodity price has increased by almost 300% generating interest in agricultural inputs to maximize soybean yield. The objective of this study was to evaluate the effect of common inputs on soybean grain yield in enhanced (high-input) and traditional (low-input) production systems. The inputs evaluated included: Rhizobia inoculant, gypsum, pyraclostrobin fungicide, lambda-cyhalothrin insecticide, and manganese (Mn) foliar fertilizer. A sixteen site-year trial was established in Ohio during 2013 and 2014. Rhizobia inoculant was seed applied before planting, gypsum was applied at the VC growth stage (unrolled unifoliate leaves), and fungicide, insecticide, and Mn foliar fertilizer were applied at the R3 growth stage (initial pod development). Measurements of percent leaf area affected by foliar disease and insect defoliation and Mn and sulfur (S) concentration in leaves were collected at six site-years. The omission of pyraclostrobin from the enhanced production system significantly reduced yield in five of sixteen site-years by 0.21 to 0.79 Mg ha-1, but its addition to a traditional system increased yield significantly at only one of sixteen site-years by 0.47 Mg ha-1 Soybean yield was influenced by fungicide application when fields had disease present, above average yield (>3.5 Mg ha-1), and received >25 cm of precipitation in June and July. During 2013 and 2014, with established corn/soybean rotations, no S or Mn deficiencies, and minimal insect pressure, there were limited effects of inoculant, gypsum, insecticide, and Mn foliar fertilizer on grain yield. The data indicate a very small potential for high-input production systems to enhance crop yield without the presence of diseases, insects, or nutrient deficiencies. Knowledge of potential yield limiting factors is useful in identifying inputs that will increase soybean yield on a field by field basis.

Committee: Laura Lindsey (Advisor); Anne Dorrance (Committee Member); Jim Metzger (Committee Member) Subjects: Agriculture; Agronomy; Plant Pathology; Plant Sciences

Master of Science in Engineering, University of Akron, 2014, Civil Engineering

The Ohio Department of Transportation (ODOT) recently implemented global chemical stabilization for new construction or repair involving major road projects. Pavement heave caused the failure of the road surfaces in three projects in Lake County, Ohio. Subsequent soil investigation revealed surface heave was caused by soil swell from the formation of a calcium alumina sulfate hydrate, ettringite (Ca6Al2(SO4)3(OH)12•26H2O) which may occur in sulfate bearing soils chemically stabilized with lime. Failure of pavement in these three projects caused ODOT to question the whether other regions within Ohio had subgrades with high soluble sulfate concentrations. This report is an investigation into natural and anthropogenic sources of sulfate (SO4) in Ohio soils evaluated via literature review and soil testing. The ODOT provided just under 350 soil samples from 39 different counties throughout the state for assessment of soil chemistry and mineralogy. Soluble SO4, often the primary controlling factor in degree of ettringite formation, was measured within soils using colorimetric methods. Several soils were additionally tested for total metal (Al, Fe and Cr) concentrations using acid digestion and inter coupled plasma optical emissions spectrometry (ICP-OES). Total Al concentration within soils was analyzed, as Al and SO4 are the chemicals within ettringite which have their primary source as the prestabilized soil. Total Fe was assessed as a marker for potential areas where sulfate would have formed from the oxidation of pyrite (FeS2). Total Cr concentration was tested as chromate (CrO4) can be a replacement group for SO4 within the ettringite structure. Additionally initial review of literature identified chromite ore processing residue remediation as a potential source of excess SO4 in soils. Finally, soil mineralogy was analyzed via x-ray diffraction (XRD). Results indicate Lake County, Ohio is not the only region with Ohio where ODOT should expect subgra (open full item for complete abstract)

Committee: Teresa Cutright Dr (Advisor); John Senko Dr (Committee Member); Ala Abbas Dr (Committee Member) Subjects: Civil Engineering; Environmental Engineering; Geochemistry; Geotechnology; Transportation

Master of Science, The Ohio State University, 2011, Civil Engineering

The goal of this research is to develop a flowable grout mix consisting of flue gas desulfurization (FGD) gypsum and fly ash that can be economically placed in mine voids and possibly re-mined along with coal in abandoned and active coal mines to enhance coal recovery. The grout mix is intended to have properties similar to the regional coal. The grout has to be strong enough to stabilize the voids, but weak enough to be re-mined without damaging mining equipment. Beneficially used FGD gypsum and fly ash will no longer need to be land-filled at an expense to the generator and the environment, but can be used to benefit the environment, the coal mining company, and the generator. The grout is not intended to be a permanent fixture in the void spaces; it can be poured, set, and then may be partially excavated along with the surrounding coal. The main properties of the grout investigated in this study were the flowability, unconfined compressive strength, and shrinkage potential. Additional properties investigated included the hydraulic conductivity, solubility, consolidation, and swell potential of the grout. The testing program has shown that FGD gypsum and fly ash flowable grouts amended with cement perform satisfactorily in laboratory testing. The grout mixes with higher concentrations of FGD gypsum took longer to develop strength, but continued to gain strength during the 90 day curing period. The strengths at 90 days of curing were not significantly affected by the proportion of FGD gypsum and fly ash, but largely dependent on the cement content. The strength development with curing time was mainly based on the proportions of FGD gypsum and fly ash. The test mixes ranged in fly ash to FGD gypsum ratios of 1:1 to 9:1 and included 0 to 10% cement in 2.5% increments. The cement free mixes did not increase in strength with curing time. The 7.5% cement mixes achieved the minimum design strength of about 400 psi or more at 28 to 90 days of curing. Mixes with cement c (open full item for complete abstract)

Committee: Tarunjit Butalia PhD (Advisor); Frank Croft PhD (Committee Member); William Wolfe PhD (Committee Member) Subjects: Civil Engineering

Master of Science, The Ohio State University, 2010, Civil Engineering

In order to reduce air pollution resulting from the combustion of coal in electric utility boilers, utilities that operate coal-fired power plants have installed air pollution control technologies. While airborne pollution has been significantly curtailed, these methodologies have significantly increased the amount of solid byproducts generated, most of which are currently landfilled. In the Appalachian region of the US, a large number of abandoned coal mines exist, many with dangerous highwalls and pits. These abandoned highwalls pose a safety risk and many are sources of acid mine drainage that can compromise the quality of the ground water and nearby streams. In this thesis, the above two issues are addressed and the utilization of coal combustion by-products in mine reclamation work has been studied. This study is focused on the use of FGD (Flue Gas Desulfurization) gypsum in the reclamation of abandoned coal mine highwalls. The main objective of this research is to investigate the potential use of FGD gypsum (in the combination with fly ash and lime) as a backfill material for reclaiming abandoned highwalls. FGD gypsum and a mixture of FGD gypsum, fly ash, and lime are studied as a potential highwall backfill material. Several laboratory tests (e.g. compaction, strength, permeability, and solubility) are performed. The substitution of FGD gypsum with fly ash did not appreciably change the permeability or strength of the FGD gypsum. However, the addition of lime to the mixture of FGD gypsum and fly ash reduced the permeability and increased the strength by an order of magnitude. Solubility of the FGD gypsum mixes studied was found to be low. In order to check the stability of a reclaimed highwall backfill, the factor of safety was evaluated using a commercial analyses program for a demonstration site close to the Conesville power plant. The slope stability analyses indicated that FGD gypsum or a mixture of FGD gypsum and fly ash gives a factor of safety more (open full item for complete abstract)

Committee: William Wolfe PhD (Advisor); Tarunjit Butalia PhD (Advisor); Fabian Tan PhD (Committee Member) Subjects: Civil Engineering; Environmental Engineering; Geotechnology

Master of Science, The Ohio State University, 2009, Civil Engineering

The goal of this study is to understand the environmental impacts associated with using FGD gypsum for abandoned mine land reclamation (AMLR) in Ohio. There are over 200,000 acres of abandoned strip mines and over 600,000 acres of abandoned underground mines throughout Ohio that cause physical and chemical hazards to surrounding waterways, soil systems, and wildlife. Ten abandoned mine lands (AMLs) in eastern Ohio were reviewed in order to classify the different types of AMLs and build model scenarios. FGD gypsum samples from two different coal combustion power plants were tested in order to characterize the leaching behavior of the material under a variety of conditions. The USEPA Methods 1311 (TCLP) and 1312 (SPLP) were used alongside a three-tiered framework developed by Kosson et al. In order to assess the overall impacts of using FGD gypsum for AMLR, a Life Cycle Assessment (LCA) was conducted to calculate output emissions and energy consumption. A combination of conventional, ecological, and economic input-output LCA were used in this study.The TCLP and SPLP results yielded concentrations of regulated constituents well below Ohio standards for beneficial use application. Thus, according to such standards the FGD gypsum samples can be classified as nonhazardous substances that present no significant impact on groundwater or risk to public health. The results from the three-tiered Kosson et al. framework provided evidence that the leaching of Ca, S, and SO4 is not necessarily affected by pH, but is mainly dependent on the solubility of gypsum. Some constituents, such as Mg and Mn, were dependent upon pH while other showed trends as a function of time. For instance, a majority of the available B was extracted in each experiment and concentration increased over 8 days, but did not change in response to varying pH. Less than 0.02% of Hg was available for leaching in each experiment and decreased over time, suggesting that long-term leaching of Hg is potentially not (open full item for complete abstract)

Committee: Harold Walker PhD (Advisor); Linda Weavers PhD (Committee Member); Tarunjit Butalia PhD (Committee Member) Subjects: Civil Engineering; Environmental Engineering

Master of Science (MS), Wright State University, 2013, Chemistry

Mineral dissolution plays a significant role in geochemical processes such as carbon sequestration and isotope geochemistry. While factors such as temperature, pressure, and solution chemistry have been widely studied, the effects of sample history and surface morphology on dissolution rates have been studied to a lesser extent. This research focuses on the dissolution of cleaved, polished, and reacted samples of the atomically flat natural {010} cleavage plane of gypsum (CaSO4·2H2O) to further investigate upon the effect of sample history. Gypsum was chosen as the mineral of interest because of its planar crystal surface and relatively fast dissolution rate. Chemical dissolution rates as well as changes in surface morphologies were determined for cleaved, polished, and reacted crystals exposed to undersaturated solutions in continuously stirred, free–drift, batch reactors. Results from chemical rate determination showed a history effect as dissolution rate decreased in consecutive dissolution runs for polished samples. For cleaved samples, relatively slow initial dissolution rates were observed. Surface morphology development showed that cleaved samples initially dissolved through etch pit nucleation and growth, while polished samples initially dissolved through step retreat. After dissolution, both cleaved and polished surfaces only showed step bunches along the [001] direction suggesting that both cleaved and polished crystals will eventually have similar surface morphologies and dissolution rates. In conclusion, surface morphology and thus sample preparation affect the initial dissolution rates on the (010) surface of gypsum. Therefore, sample preparation is a variable that should be accounted for in laboratory experiments.

Committee: Steven R. Higgins Ph.D (Advisor); David A. Grossie Ph.D (Committee Chair); Andrew G. Stack Ph.D (Committee Member); David A. Dolson Ph.D (Committee Member); Ioana E.P. Sizemore Ph.D (Committee Member) Subjects: Chemistry; Geochemistry; Geology; Mineralogy