Ben Stuart

Growth optimization of algae for biodiesel production

Aims:  Algae are favourable as a biofuel source because of the potential high oil content and fast generation of biomass. However, one of the challenges for this technology is achieving high oil content while maintaining exponential or high growth of the organism. Introducing a two‐stage reactor to optimize both growth and oil content of the algae could be a solution to this hurdle. The aim of this study was to determine the reactor design parameters of the first‐stage reactor, which would optimize growth of two algal strains, Oocystis sp. and Amphora sp.

Role of sulfur-reducing bacteria in a wetland system treating acid mine drainage

This report describes a twenty month case study of a successive alkalinity producing system (SAPS) treating a strong acid mine drainage (AMD) source in Coshocton County, Ohio. Prior to the commencement of the project, a large volume of black amorphous sludge had accumulated in several of the constructed wetlands. The sludge was found to be 43% organic, with very high concentrations of sulfur, iron, aluminum, and acidity. Based on several biological, physical, and chemical analyses, the sludge was determined to be an anaerobic biofilm with a large population of sulfur-reducing bacteria and a high mineral content due to the formation of iron sulfide and aluminum precipitates. On average the system performed well, generating 26 kg CaCO3/d of alkalinity and capturing 5.0 kg/d of iron and 1.7 kg/d of aluminum. Several simple performance analysis tools were presented in this work. By comparing the pollutant influent and effluent loading, it was determined that the SAPS was performing at capacity and over the past year increased effluent concentrations were due to increased influent loadings and not system deterioration. Further, by performing a detailed cell-by-cell loading analysis of multiple chemical components, the alkalinity generated by limestone dissolution and by sulfate reduction was determined. Interestingly, 61% of the alkalinity generation in the vertical flow wetlands was due to sulfur-reducing bacteria activity, indicating that sulfur-reducing bacteria may play a more significant role in SAPS than expected.

Characterization of Municipal Waste Combustion Air Pollution Control Residues as a Function of Particle Size

ABSTRACT Air Pollution Control (APC) residues from Municipal Waste Combustion (MWC) typically contain high concentrations of potentially toxic metals. APC residues, consisting of fly ash and lime spray drier scrubber residue, were sieve separated into six size fractions. Residue characterization included physical and morphological classification and chemical speciation. Elemental distributions as a function of particle size indicated parabolic distributions for matrix species and sigmoidal distributions for volatile species. Unreacted lime in the scrubber residue preferentially was present in the smallest fractions which greatly altered the elemental distribution profiles. Mathematical correction for this highly water soluble portion of the residue normalized the data which showed extreme similarity between facilities. Parabolic profiles became nearly linear with negative slopes and sigmoidal trends were transformed into exponential curves. This included adjusted lead concentrations approaching 2 wt% and ...

Membrane-based wet electrostatic precipitation

Abstract Emissions of fine particulate matter, PM2.5, in both primary and secondary form, are difficult to capture in typical dry electrostatic precipitators (ESPs). Wet (or water-based) ESPs are well suited for collection of acid aerosols and fine particulates because of greater corona power and virtually no re-entrainment. However, field disruptions because of spraying (misting) of water, formation of dry spots (channeling), and collector surface corrosion limit the applicability of current wet ESPs in the control of secondary PM2.5. Researchers at Ohio University have patented novel membrane collection surfaces to address these problems. Water-based cleaning in membrane collectors made of corrosion-resistant fibers is facilitated by capillary action between the fibers, maintaining an even distribution of water. This paper presents collection efficiency results of lab-scale and pilot-scale testing at First Energy’s Bruce Mansfield Plant for the membrane-based wet ESP. The data indicate that a membrane wet ESP was more effective at collecting fine particulates, acid aerosols, and oxidized mercury than the metal-plate wet ESP, even with ∼15% less collecting area.

Solvent Extraction and Characterization of Neutral Lipids in Oocystis sp.

Microalgae are a favorable feedstock for bioproducts and biofuels due to their high oil content, fast growth rates and low resource demands. Solvent lipid extraction efficiency from microalgae is dependent on algal strain and the extraction solvent. Four non-polar extraction solvents were evaluated for the recovery of neutral cellular lipids from microalgae Oocystis sp. (UTEX LB2396). Methylene chloride, hexane, diethyl ether, and cyclohexane were selected as the extraction solvents. All solvent extracts contained hexadecanoic acid, linoleic acid and linolenic acid; accounting for 70% of total lipid content with a proportional wt% composition of the three fatty acids, except for the hexane extracts that showed only hexadecanoic acid and linoleic acid. While not statistically differentiated, methylene chloride proved to be the most effective solvent for Oocystis sp. among the four solvents tested with a total average neutral lipid recovery of 0.25% of dry weight followed by diethyl ether (0.18%), cyclohexane (0.14%) and hexane (0.11%). This research presents a simple methodology to optimize the selection of lipid specific extraction solvents for the microalgal strain selected.

Design, Construction, and Validation of an Internally Lit Air-Lift Photobioreactor for Growing Algae

A novel 28 L photobioreactor for growing algae was developed from a previous bubble column system. The proposed design uses the air lift principle to enhance the culture circulation and induce light/dark cycles to the microorganisms. Optical fibers were used to distribute photons inside the culture media providing an opportunity to control both light cycle and intensity. The fibers were coupled to an artificial light source, however the development of this approach aims for the future use of natural light collected through parabolic solar collectors. This idea could also allow the use of non-clear materials for photobioreactor construction significantly reducing costs and increasing durability. Internal light levels were determined in dry conditions and were maintained above 80 µmol/(s•m2). The hydrodynamic equations of the air lift phenomena were explored and used to define the geometric characteristics of the unit. The reactor was inoculated with the algae strain Chlorella sp. and sparged with air. The reactor was operated under batch mode and daily monitored for biomass concentration. The specific growth rate constant of the novel device was determined to be 0.011 h-1, similar to other reactor designs reported in the literature, suggesting the proposed design can be effectively and economically used in carbon dioxide mitigation technologies and in the production of algal biomass for biofuel and other bioproducts.

Carbon Footprint Analysis of Source Water for Hydraulic Fracturing: A Case Study of Mine Water Versus Freshwater

In the face of climate change, less carbon intensive fuels are being sought. Natural gas has been perceived as a transition fuel, producing less CO2 when burned than coal, but it is not a renewable resource. Hydrocarbon-rich shale formations contain natural gas, natural gas condensate, and oil production potential, and the extraction of these compounds has allowed the USA to become one of the largest global producers of natural gas. Horizontal drilling and hydraulic fracturing are used to extract the shale gas, but hydraulic fracturing of one well typically requires between 7 and 19 million L of water. One option being explored is the use of treated mine water as an alternative to freshwater. The Marcellus and Utica shale formations underlie much of the eastern USA, and the Utica Shale is being pursued for its high natural gas potential in eastern Ohio. Permits for wells are being approved, but concerns about the water source for hydraulic fracturing fluid are increasing. We analyzed the carbon footprints of three different water sources: treated mine water from Corning, Ohio, freshwater from the Ohio River, and freshwater from Seneca Lake near the well site. CO2 emissions for each source were calculated during pumping, transportation, and treatment of the water for a one-time well use and annual use. The primary productivity increase that occurred after removal of mine discharge or reduction due to extraction from freshwater sources was also calculated. Annually, using treated mine water would emit 110,000 t of CO2-e (CO2 equivalent) if trucked to a treatment plant or 90,000 t of CO2-e if treated on-site, while using water from the Ohio River would emit 2,000 t of CO2-e, and using water from Seneca Lake would emit 4,500 t of CO2-e, annually. Of course, decreasing the amount of unpolluted freshwater used has other environmental benefits.ZusammenfassungIm Angesicht des Klimawandels werden Brennstoffe geringerer Kohlenstoffintensität gesucht. Erdgas wurde als Übergangsbrennstoff wahrgenommen, weil es weniger CO2 produziert als Kohle, aber es ist keine erneuerbare Ressource. Kohlenwasserstoffreiche Tonsteinformationen enthalten Erdgas, Erdgaskondensate und das Potential, Erdöl zu produzieren. Die Extraktion dieser Stoffe hat es erlaubt, daß die USA zu einem der größten globalen Produzenten von Erdgas wurde. Horizontalbohrungen und hydraulisches Fracken werden zur Förderung von Schiefergas genutzt, aber hydraulisches Fracken einer Bohrung benötigt typischerweise zwischen 7 und 19 Millionen L Wasser. Eine untersuchte Option ist die Verwendung von behandeltem Bergbauwasser als eine Alternative zu Süßwasser. Die Marcellus und Utica Tonformationen unterlagern weite Teile der östlichen USA,und der Utica Tonstein wird im östlichen Ohio wegen seines hohen Erdgaspotentiales aufgesucht. Bewilligungen für Bohrungen werden erteilt, aber Sorgen über die Herkunft des Wassers für das hydraulische Frackfluid nehmen zu. Wir haben den CO2-Fußabdruck von drei unterschiedlichen Wasserquellen untersucht: behandeltes Bergbauwasser von Corning, Ohio, Süßwasser aus dem Ohio Fluß, und Süßwasser aus dem Seneca See in der Nähe des Bohrplatzes. CO2-Emissionen für jede Quelle wurden für das Pumpen, den Transport und für die Wasseraufbereitung für den Fall einer einmaligen Nutzung oder einer mehrfachen Verwendung über ein Jahr berechnet. Die Zunahme primärer Produktivität, welche durch die Beseitigung des Bergbauwasseraustrittes entstand oder die Reduktion infolge der Entnahme aus Süßwasserquellen wurde ebenfalls berechnet. Für den Fall des Lastwagentransportes zu einer Wasseraufbereitung würde die Verwendung behandelten Bergbauwassers eine jährliche Emission von 110.000 t CO2-e (CO2-Äquivalent) bewirken, bei einer Behandlung vor Ort jedoch nur 90.000 t CO2-e, während die Nutzung von Wasser aus dem Ohio Fluß jährlich in 2.000 t CO2-e, und von Wasser aus dem Seneca See 4.500 t CO2-e resultierte. Selbstverständlich hätte die Verringerung der Nutzung sauberen Süßwassers andere Umweltvorteile.ResumenEn vista del cambio climático, los combustibles en base carbón tienen menor demanda. Gas natural está siendo percibido como un combustible de transición, produciendo menos CO2 en la combustión que el carbón, pero no es una fuente renovable. Formaciones de esquistos bituminosos ricos en hidrocarburos, gas natural condensado, potencial de producción de petróleo y la extracción de estos compuestos ha permitido que EEUU se convirtiera en uno de los mayores productores globales de gas natural. Las perforaciones horizontales y la fractura hidráulica están siendo usados para extraer el gas de los esquistos bituminosos, pero la fractura hidráulica de un pozo requiere entre 7 y 19 millones L de agua. Una de las opciones que está siendo explorada es el uso de agua de mina tratada como una alternativa frente al agua dulce. Las formaciones de esquistos bituminosos Marcellus y Utica están en el subsuelo de buena parte de EEUU oriental y el esquisto Utica es requerido por su alto potencial en gas natural en Ohio oriental. Los permisos para pozos están siendo aprobados pero la preocupación sobre la fuente de agua para fractura hidráulica se está incrementando. Analizamos las huellas de carbón de tres fuentes de agua diferentes: agua de mina tratada de Corning, Ohio, agua dulce del Río Ohio y agua dulce del Lago Seneca cerca del sitio del pozo. Las emisiones de CO2 para cada fuente fueron calculadas durante el bombeo, transporte y tratamiento de agua para el uso del pozo una vez y para el uso anual. Se calculó también la producción primaria que ocurrió después de la remoción de la descarga de mina o la reducción debido a la extracción de fuentes de agua dulce. Anualmente, usando agua de mina tratada se emitirían 110.000 t de CO2-e (CO2 equivalente) si se transportara hasta una planta de tratamiento o 90.000 t de CO2-e si se tratara en el sitio, mientras que usando agua del Río Ohio se emitirían 2.000 t de CO2-e y usando agua del Lago Seneca se emitirían 4.500 t de CO2-e, anualmente. Por supuesto, el descenso de la cantidad de agua dulce contaminada usada tiene otros beneficios ambientales.

GIS-based Planning Support System for Waste Stream and Algal Cultivation in Residential Construction

Technologies of alternative energy generation for residential communities using algal material, involving the construction of bioreactors with solar cells, storage of raw materials, construction of central plants for conversion of bio-fuels, and delivery systems to users, will have different design impacts at different scales. This paper intends to define basic design and planning parameters for residential construction in accordance with the scientific knowledge and technical criteria available regarding the potential for algal biofuel production and sustainable urban living. This paper suggests a framework of GIS-based planning support system for informing processes of data representation, performance assessment and design for the coupled algae cultivation and urban systems.

Numerical Investigation of the Flow Profiles in the Electrically Enhanced Cyclone

Abstract A numerical model for simulation of the electrohydrodynamic flow in an electrically enhanced cyclone is presented. A finite element approach was applied to solve the coupled equations for the positive corona-induced electric field. Three-dimensional simulations of gas flow were carried using Reynolds-Averaged Navier-Stokes equations including the Reynolds stress model and the electrohydrodynamic effect. Numerical results show that the change in the flow profile because of the influence of the corona-induced electric field is apparent when the inlet flow rate is low but is negligible at higher flow rates.

IDENTIFICATION AND ANALYSIS OF ACID MINE DRAINAGE SOURCES IN THE BLACK FORK SUB-WATERSHED

The Moxahala Creek watershed in southeast Ohio was recognized by the state of Ohio as one of the most acidic watersheds in the state. Four tributaries were determined to be the primary contributors to the negative water quality. The largest by volume of these tributaries is Black Fork, which provides 20 to 25% of the total flow in Moxahala Creek. The current studys objective was to identify the causes of acid mine drainage (AMD) into Black Fork and to evaluate the effects of AMD to the sub-watershed. As a result of the current project, two coal refuse piles and numerous seeps have been acknowledged as the main sources of AMD in Black Fork. In preliminary sampling, researchers surveyed 50 stream locations to determine the streams which contribute significantly to Black Fork. At present, eighteen locations are sampled every four to six weeks. The flowrate and water quality parameters are measured on site, and samples are being analyzed for common AMD water quality indicators such as pH, acidity, total iron, and sulfate. A wetland was constructed in 1994 to treat the affected water from one of the identified seeps before discharging into Black Fork. This wetland was evaluated before and after vegetation was established to assess the wetlands effectiveness in reducing AMD pollutants. Biological assessments of fish populations, macroinvertebrates, and algal species were also performed throughout the sub-watershed in order to determine number and diversity of species present in the habitat. This report presents water quality data, which gives a basic understanding of the dynamics of the Black Fork sub-watershed. A GIS database was developed for data management and is also demonstrated. Additional