Detailed petrography, geochemistry, and palynology together describe the depositional environments and paleoecology of an abandoned meander-fill system in western Kentucky. Oriented block petrography reveals alternating clay-rich and attrinite-rich zones of variable thickness. Woody tissues, where present, do not show dessication features and deflation layers could not be identified. Overall, petrography is indicative of a topogenous mire. Mire palyno-assemblages are less diverse than assemblages reported from clays in the region. Castanea-Cupuliferoidaepollenites assemblages dominate the entire system and other tree pollen are common; fungal spores are relatively uncommon. Weighted statistical analyses reveal ecological groupings beyond this dominance and define botanical succession within the mire. The nearestliving- relative method for determining paleoclimate indicates temperate to warm temperate conditions during deposition. Palynology indicates a Claibornian stage, middle Eocene age for the deposit.

Thesis. 1976. Sc.D.--Massachusetts Institute of Technology. Dept. of Chemical Engineering. / Microfiche copy available in Archives and Science. Incorrect foliation: leaves 204-219 are bound between leaves 238 and 239. / Vita. / Bibliography: leaves 385-427. / by John H. Pohl. / Sc.D.

Abstract not available

Increasing environmental legislations on pollutant emissions originated from fossil fuel combustion and intention of increasing the life of existing fossil fuels give rise to the use of renewable sources. Biomass at this juncture, with its renewable nature and lower pollutant emission levels becomes an attractive energy resource. However, only seasonal availability of biomass and operation problems caused by high alkaline content of biomass ash restrict its combustion alone. These problems can be overcome by co-combustion of biomass with lignite. With its high fuel flexibility and high combustion efficiency, fluidized bed combustion is the most promising technology for co-firing. To improve and optimize the operation of co-firing systems a detailed understanding of co-combustion of coal and biomass is necessary, which can be achieved both with experiments and modeling studies. For this purpose, a comprehensive system model of fluidized bed combustor, previously developed and tested for prediction of combustion behaviour of fluidized bed combustors fired with lignite was extended to co-firing lignite with biomass by incorporating volatile release, char combustion and population balance for biomass. The model predictions were validated against experimental measurements taken on METU 0.3 MWt AFBC fired with lignite only, lignite with limestone addition and about 50/50 lignite/olive residue mixture with limestone addition. Predicted and measured temperatures and concentrations of gaseous species along the combustor were found to be in good agreement. Introduction of biomass to lignite was found to decrease SO2 emissions but did not affect NO emissions significantly.

The facies architecture and geometry of stratigraphic surfaces within a lignite bearing interval of the Paleocene upper Calvert Bluff Formation is mapped on a photomosaic of the 150 ft (50 m) high and 12,000 ft (4km) long “C” area highwall of Big Brown Mine, near Fairfield, Texas. Observed bedding and facies architecture are interpreted in terms of temporal changes, depositional environments and sequence stratigraphic setting. A three dimensional grid of 89 subsurface logs is correlated to this photomosaic to characterize log response patterns of facies. Six facies are observed: 1) lignite, 2) interdistributary bay mud, 3) prograding delta, 4) delta top mud, 5) distributary channels, and 6) incised valley fill. The six facies were defined by a combination of mapped photomosaic observations and subsurface log correlations. The lignite deposit formed in a low depositional energy, low sediment input, high-organic productivity interchannel basin. Overlying mud records overbank flooding followed by avulsion and progradation of delta deposits. Tidal-flat deposits overlying prograding delta deposits record fluctuating energy conditions on the emerging delta top. Channel deposits cutting into the delta top record lateral channel migration across delta top floodplains. These regressive delta deposits are capped by a local incised sequence boundary overlain by fluvial channel deposits inferred to have allowed sediment to bypass further basinward during lowstand. A sheet of channel deposits capping this highwall exposure records more recent erosion, followed by development of modern soil horizons. The Big Brown Mine highwall exposes a relatively complete high-frequency Paleocene stratigraphic sequence developed in an area landward of the shoreline position during maximum transgression, that progresses upsection from: 1) highstand alluvial flood basin coals, 2) a thin condensed maximum flooding interdistributary shale, 3) a thick succession of regressive deltaic strata, and 4) a high-relief, sequence-bounding erosion surface overlain by a lowstand to transgressive fill of channel deposits. Correlations with regional Wilcox Group stratigraphic studies spanning coeval shoreline and shelf strata indicate that this high-frequency sequence is within the transgressive systems tract of a 3rd order stratigraphic sequence. It appears that high-frequency sequences of sub-regional extent control the complex distribution of coal seams within central Texas.

Over the last 30 years, lignite has become an important energy resource for the State of Texas. Production of lignite involves strip mining large areas of land in the Texas Gulf Coast region. Lignite at the Big Brown Mine, Freestone County, Texas, is produced from fluvial-deltaic sediments of the Calvert Bluff Formation of the Paleocene-Eocene Wilcox Group. Mining processes mix overburden material resulting in a spoil that is more homogeneous than the original unmined material over the area of the mine. The effects of mining on the environment are wide and varied, but mining is especially disruptive to the groundwater system. Groundwater recovery begins immediately after the spoil is placed, but occurs at highly variable rates. Hydrogeologic properties change rapidly in the first few years after mining and much of the groundwater recovery is dependent on the infiltration capacity of the spoil material. Resaturation of shallow spoil aquifers at the Big Brown Mine occurs at rates ranging from 0.6 to 3.0 m/yr (2-10 ft/yr). Recharge to the groundwater system is principally from direct infiltration of precipitation with variable resaturation rates attributed to variations in infiltration. For this study, four sites at the Big Brown mine were chosen for characterization. Three sites, designated fields C-13, C-24 and C-32, are located in reclaimed areas of the mine and range in age from 9 to 14 years old, while the fourth site is located in an unmined area (UM) between the two active mining pits. Infiltration rates were quantified using a drip infiltrometer to simulate rainfall. Results show that mining and reclamation processes can reduce infiltration rates by as much as 53 percent from the unmined values. Unmined areas show infiltration rates ranging from 12 to 30 cm/hr (4.7-11.8 in/hr) with a mean value of 20 cm/hr (7.9 in/hr). Mined areas show infiltration rates ranging from 3 to 22 cm/hr (1.2-8.7 in/hr) with a mean value of 9 cm/hr (3.5 in/hr). These rates vary significantly over the area of a single field resulting in high standard deviations, but a comparison of mean infiltration rates between the three mined areas show much less variation. It is unlikely that the small variations seen in the infiltration rates of fields C-13 and C-24 can, by themselves, account for the large variations in resaturation rates for these fields. Infiltration rates vary in response to changes in soil moisture content, spoil heterogeneity, soil mineralogy, and method of spoil placement. Higher values of infiltration occur when the soils are dry, generally from late spring to early fall. Differences in soil texture had less effect on infiltration rates than was hypothesized, with both coarse and fine grained soils showing similar values. Tracer tests, using sodium bromide as a conservative tracer and the red dye Rhodamine WT, were performed to determine if channeling of water occurs in the reclaimed soils. Trenches, cut in the dyed areas, were inspected for fractures and macropores and sampled at regular intervals for analysis of bromide concentration. Rhodamine WT showed some fractures in the soil structure, but due to a chemical reaction, sorbed strongly to the soil surface with little movement into the soil column. Concentration plots of bromide proved much more useful in determining mechanisms of flow and showed good vertical flow paths in fields C-13 and C-32. Lateral flow dominates in field C-24. Differences in flow mechanisms may best account for the variable resaturation rates seen in these fields. / text

Thesis (M.Sc.)--Memorial University of Newfoundland, 1995. / Typescript. Bibliography: leaves 75-86. Also available online.

Thesis (MSc.(Pharmacology)--Faculty of Health Sciences)-University of Pretoria, 2007.

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Heavy metals, oxyanions (NO3-, PO4-), pharmaceuticals, and dyes in aquatic environments are inevitable economic and health concerns. Ingestion of these contaminants, even in trace amounts, causes long and short-term serious threats to human health. Conventional pollutant mitigation strategies can be costly or ineffective. Due to high efficiency, simplicity, low price, adsorbent reuse, and pollutant (e.g., phosphates) recovery, adsorption has been widely used for wastewater purification. Many efficient, environmentally compatible, and cost-effective sorbents have been successfully applied in environmental remediation. Chapter I is about characterization of graphene-coated pinewood biochar hybrids and evaluation of their copper removal performances. Here, we synthesized three types of pinewood biochar-graphene composites consisting of three different graphene precursors and compared their aqueous Cu2+ removal performances against raw pinewood biochar. To the best of our knowledge, no previous work has characterized the copper decontamination by graphene-biochar hybrids. Chapter II is about thermally- and chemically-treated lignite adsorbents for phosphate remediation. We engineered a cost efficient lignite system with co-precipitated Ca2+/Mg2+ followed by pyrolysis at 600 ⁰C to remediate aqueous phosphates. Micro-sized surface deposited oxide/hydroxide/carbonate particles promoted phosphate uptake of Ca2+/Mg2+-modified-lignite by 31 and 72 times, compared to thermally treated lignite (w/o a chemical treatment) and the raw lignite, respectively. The exhausted adsorbent can act as a slow-release fertilizer, which is comparable with commercial phosphate fertilizers. Chapter III is about synthesis of activated lignite [A-L], Ca2+-modified lignite [Ca-L], and Fe3O4 nanoparticle-loaded activated lignite (Fe3O4-A-L) for phosphate remediation. Even though A-L has a very high surface area (2854 m2/g), it did not achieve much phosphate sorption. Ca-L phosphate uptake was highest due to the high concentrations of surface deposited CaCO3, CaO, and Ca(OH)2. A pH-independent (from pH 5 to 9) phosphate removal was reported by highly basic Ca-L. However, the Ca2+ leaching was highest at pH 5. Precipitation of Ca2+ phosphates/hydrophosphates is the major phosphate removal mechanism of Ca-L. Fe3O4 and Fe2O3 sites of Fe3O4-A-L enhanced phosphate adsorption capacity, 8-fold versus A-L (67.6 mg/g vs 8.0 mg/g at 25 ºC). Fe3O4-A-L remediated phosphates via inner-sphere surface complexation and precipitation.