Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 34 for “"Carbon removal"”.
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Mathematical Modeling of Carbon Removal in the A-Stage Activated Sludge System
… model (ASM) to better describe the overall removal of organic substrate, quantified as chemical oxygen demand (COD), from A-stage high rate activated sludge (HRAS) systems. This dynamic computer model is based on a modified ASM1 (Henze et al., 2000) model. It was determined early in the …
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Direct Air Capture as a Carbon Removal Solution: Analyzing Scale-Up, Cost Reduction, and Pathways for Acceleration
In addition to drastic reductions in global carbon dioxide emissions, the Intergovernmental Panel on Climate Change has stated with high confidence that carbon dioxide removal will be needed to meet the Paris Agreement temperature goals. Direct air capture is a novel carbon removal technique that …
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A bioengineering roadmap for negative emissions technologies
Negative emissions technologies that can remove carbon dioxide from the atmosphere are a critical tool to limit global temperature rise and ocean acidification. Bioengineering capabilities have not been sufficiently assessed or utilized for the development of negative emissions technologies. …
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MULTI-MODAL INTEGRATED CARBON DIOXIDE CAPTURE AND MINERALIZATION PATHWAYS FOR SUSTAINABLE HYDROGEN PRODUCTION
Scalable decarbonization efforts require the production of low-carbon hydrogen energy alternatives. Currently, more than 80% of hydrogen is produced via steam methane reforming (SMR) followed by water gas shift reaction (WGSR) pathway that produces significant CO2 emissions, regardless of the use …
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Potassium cyanide inhibition of mixed bacterial populations
… to control) to KCN based on glucose and soluble carbon removal and cell mass increase. However, the cyanide acclimated aerobic system showed the greatest overall rates of carbon removal suggesting greatest utility for treatment of cyanide bearing wastes.
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Enhanced anaerobic digestion of combined wastewater sludges through solubilization of waste activated sludge
… days, without losing VSS reduction efficiency. Carbon removal (in terms of total and soluble COD removal) actually increased with a decrease in SRT and the highest carbon removal was achieved in the exp NaOHunit. Better carbon removal was also reflected in a higher methane content of the gas. …
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Submerged-Membrane Bioreactor for the Treatment of NASA Wastewater
… utilizes both anoxic and aerobic processes for carbonaceous and nitrogenous species removal. While complete biological nitrification proved difficult due to free ammonia inhibition, by acidifying reactor feed consistent nitrification was observed. An unexpected observation was nitrite …
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New catalysts for syngas production from carbon dioxide and methane
… SEM images suggest formation of encapsulated carbon and whisker carbon.;The kinetics of CH4/CO2 reforming was studied under differential conditions over 500--600°C. The observed rates seem to follow a Langmuir-Hinshelwood type of reaction mechanism. A scheme consisting of four reactions …
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Bromine Chloride Treatment of Aqueous Gasifier Effluent
… bromine chloride was unable to reduce the total carbon concentration of the wastewater to acceptable discharge or reuse levels.</p><p>Bromine chloride addition as an aqueous solution, a liquid, and a vapor was investigated. Bromine chloride vapor gave the largest total carbon removal. Phenolic …
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A Synthesis and Optimization of Patented Direct Air Capture Technology
… technology to advance the state of the art in carbon removal to ameliorate the impacts of increasing carbon concentrations in the atmosphere.
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Carbon and nitrogen removal in a granular bed baffled reactor
… concerns for the treatment of high strength carbonaceous wastewaters in anaerobic systems is to achieve an optimum growth environment for acidogenesis and methanogenesis. Such wastewaters with high nutrient levels could cause additional problems as anaerobic units are usually designed for the …
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Moving beyond the stream reach: Assessing how confluences alter ecosystem function and water quality in freshwater networks
… networks, the sources, movement, and cycling of carbon and nutrients are shaped both by in-stream processes and the surrounding landscape. Streams receive and transport materials from upstream and terrestrial sources that support in-stream ecosystem processes and regulate downstream water …
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Techno-economic and life cycle analysis of the conversion of natural gas and biomass to hydrogen and performance carbons
… alongside the production of high-performance carbon materials to lower overall costs. It underscores the urgent need to transition away from Steam Methane Reforming (SMR) for industrial hydrogen production due to the direct carbon dioxide emissions associated with SMR. To address these …
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A study of nitrate versus oxygen respiration in the activated sludge process
… is known about microbial growth and substrate removal when nitrate respiration is employed. The primary objective of this study was to evaluate and compare microbial growth and biokinetic coefficients in an aerobic and an anoxic (anaerobic with nitrate as the terminal electron acceptor) …
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Unique templating of and applications enabled through mesoporous colloids
… detailed investigation. The first successful carbon colloidal crystal is fabricated through tailoring the surface charge of the individual colloids through a partial oxidation. This colloidal crystal was used as a unique template for a variety of materials. The templated materials penetrate …
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A spatial and temporal study of the carbon cycle; the role of carbonates in buffering Earth’s climate
… weathering and a change in the total amount of carbon in the combined ocean-atmosphere (OA) system, which is hard to square against proxy observations of invariant silicate weathering and volcanic degassing rates. Recent rethinking about carbon cycling suggests that rather than increasing …
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Climate Impact Analysis of Direct Air Capture Deployment
… relying on renewable electricity have high carbon removal efficiency and relatively low cost. Additionally, I quantify the climate impact of large-scale global DAC deployment with investments of 0.5%, 1%, 1.5%, and 2% of the global GDP. I integrate electric DAC plants powered by renewable …
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Investigation of new KOH and NaOH thermochemical cycles for hydrogen production and carbon capturing
Hydrogen production and carbon dioxide removal are two of the critical pieces to achieve ultimate sustainability target. This study develops and investigates four new versions of NaOH and KOH thermochemical cycles to combine hydrogen production and carbon dioxide removal in an integrated and …
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Modeling ocean transport and its biogeochemical impacts at global, regional, and sub-meso scales
Improving understanding of how carbon is cycled through the ocean is crucial for predicting, mitigating, and adapting to climate change. This thesis explores how horizontal and vertical currents at different scales impact biogeochemical cycling through the redistribution of tracers such as …
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Colloid Formation for the Removal of Natural Organic Matter during Iron Sulfate Coagulation
Removal of organic matter is increasingly important to drinking water utilities and consumers. Organic matter is a significant precursor in the formation of disinfection by-products (DBPs). The maximum contaminant levels for (DBPs) are decreasing and more DBPs are believed carcinogenic. Traditional …
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