The rapid accumulation of municipal solid waste is a significant environmental concern in our rapidly growing world. Due to its low cost, high energy recovery and limited environmental impact anaerobic digestion (AD) is a promising solution for stabilizing the organic fraction of municipal solid waste (OFMSW). Hydrolysis is often the rate-limiting step during AD of wastes with high solid content; this step can be accelerated by pretreatment of waste prior to AD. This thesis presents the results of alkaline pretreatment of OFMSW using NaOH and KOH. Four different pH levels 10, 11, 12 and 13 at two temperatures 23±1°C and 80±1°C were examined to study the effects of the pretreatment on (i) enhancing the solubility of the organic fraction of the waste, and (ii) enhancing the AD process and the biogas production. The effects on solubility were investigated by measuring changes in the soluble COD (SCOD) concentrations of pretreated wastes and the enhanced AD was investigated by measuring volatile solids (VS) destruction, total COD (TCOD) and SCOD removal in addition to biogas and methane production using biochemical methane potential (BMP) assay and semi-continuous laboratory reactor experiments. Pretreatment at pH 13 at 80±1°C demonstrated the maximum solubility for both NaOH and KOH pretreated samples; however the BMP analysis demonstrated that pretreatment at pH 12 at 23±1°C showed the greatest biogas yield relative to the removed VS for both chemicals. Thus pretreatment at pH 12 at 23±1°C using NaOH and KOH were examined using semi-continuous reactors at three different HRTs: 10, 15 and 20 days. Pretreatment demonstrated a significant improvement in the AD performance at SRTs of 10 and 15 days.

Graduation date: 1993

The rapid accumulation of municipal solid waste is a significant environmental concern in our rapidly growing world. Due to its low cost, high energy recovery and limited environmental impact anaerobic digestion (AD) is a promising solution for stabilizing the organic fraction of municipal solid waste (OFMSW). Hydrolysis is often the rate-limiting step during AD of wastes with high solid content; this step can be accelerated by pretreatment of waste prior to AD. This thesis presents the results of alkaline pretreatment of OFMSW using NaOH and KOH. Four different pH levels 10, 11, 12 and 13 at two temperatures 23±1°C and 80±1°C were examined to study the effects of the pretreatment on (i) enhancing the solubility of the organic fraction of the waste, and (ii) enhancing the AD process and the biogas production. The effects on solubility were investigated by measuring changes in the soluble COD (SCOD) concentrations of pretreated wastes and the enhanced AD was investigated by measuring volatile solids (VS) destruction, total COD (TCOD) and SCOD removal in addition to biogas and methane production using biochemical methane potential (BMP) assay and semi-continuous laboratory reactor experiments. Pretreatment at pH 13 at 80±1°C demonstrated the maximum solubility for both NaOH and KOH pretreated samples; however the BMP analysis demonstrated that pretreatment at pH 12 at 23±1°C showed the greatest biogas yield relative to the removed VS for both chemicals. Thus pretreatment at pH 12 at 23±1°C using NaOH and KOH were examined using semi-continuous reactors at three different HRTs: 10, 15 and 20 days. Pretreatment demonstrated a significant improvement in the AD performance at SRTs of 10 and 15 days.

No description available.

This work presents the first alkaline redox flow battery (a-RFB) based on the coordination chemistry of cobalt(III/II) and iron(III/II) with amino-alcohol ligands in concentrated NaOH([subscript aq]). The a-RFB was developed by carrying out systematic structural and electrochemical characterizations of various redox-active coordination compounds to find the most suitable candidates for electrochemical energy storage. In the characterization studies, particular attention was given to the redox couple Fe(III/II)- TEA, where TEA = triethanolamine, because of its importance in the fields of supramolecular chemistry, magnetic memory films, and electrochemical energy storage. The structures of Fe(III)-TEA in the solid state and in alkaline solution are reported for the first time. Moreover, experimental evidence is presented for the existence of an EC reaction in the heterogeneous reduction of Fe(III/II)-TEA in concentrated base. Furthermore, experiments were carried out to study the reactivity of Fe(II)-TEA with O2. This is important because O2 reacts spontaneously with Fe(II)-TEA to produce hydrogen peroxide, decreasing the charging-discharging capacity of the a-RFB. The reduction of oxygen by Fe(II)-TEA in concentrated base was studied by UV-Vis spectroscopy and coulometric titrations. Additionally, a new method for the quick identification of redox couples with slow EC reactions, k[subscript f] < 0.1 s-1, is presented. The new method is based on scanning electrochemical microscopy (SECM) and consists of creating a thin-layer cell between the tip and substrate electrode. During analysis of a redox couple, the tip reports a current transient proportional to the decaying concentration of the product of the E reaction, from which an apparent forward rate constant for the C reaction can be determined. This method was designed for the field of RFB research, where the identification of redox couples with no EC reactions is necessary to ensure that a battery can run for thousands of cycles. Lastly, surface oxidation of polycrystalline Ir ultramicroelectrodes was studied by the surface interrogation mode of SECM (SI-SECM), using Fe(II)-TEA as the titrant. This was done to demonstrate the existence of hydrous oxides of Ir(IV) and Ir(V) prior to the onset of oxygen evolution in concentrated base. Numerical simulations were carried out using commercial software and were used to validate the experimental results reported in this work. / text

Organic phosphorus (P$ sb{ rm o}$) in farm animal wastes must be mineralized to inorganic P for subsequent plant use. This study was conducted to determine if feed additives affect P$ sb{ rm o}$ mineralization, manure decomposition, and plant growth. Feed additives in aqueous systems affected the P mineralization of inositol hexaphosphate by phytase and of adenosine monophosphate by alkaline phosphatase. Pronounced effects were produced by bacitracin and both enzymes and by neomycin on phytase. Feed additives in dairy cattle (Bos taurus L.) manure produced effects on microbial activity as measured by gas production that differed from those produced on fecal phosphatase activity. Additives applied directly or with manure to Ste. Rosalie clay, Greensboro loam, or silica sand had no effect on barley (Hordeum vulgare L.) yield but did produce additive, rate, growth medium, and manure dependent effects on plant P concentration and soil phosphatase activity. Therefore, each feed additive must be independently evaluated to determine its effect on biological systems.

<p>The current work focuses on the synthesis and characterization of nano-devices with potential application in alkaline electrolysis and secondary polymer lithium ion batteries.</p>

The first documented carbonatites in Manitoba occur as dykes and pods up to 15 meters in length and several meters in width at Eden Lake hosted in a post-orogenic syenitic complex within the Trans-Hudson Orogen. The carbonatites consist dominantly of calcite with lesser clinopyroxene, feldspar, apatite and titanite. Primary and xenocrystic clinopyroxene have distinct compositions, whereas xenocrystic feldspar has well-developed plagioclase and alanite rims. The whole-rock major- and trace-element composition of the carbonatite is consistent with global averages for calcio-carbonatites. Stable-isotope compositions of calcite indicate an igneous origin; the low δ13C ratios may reflect the influence of subducted sedimentary carbonate. A zircon age of 1815±8 Ma corresponds with the time of emplacement, whereas younger titanite ages reflect local thermal history. Although field relations suggest a genetic link to the host syenites, whole-rock geochemical data is incompatible with immiscibility or crystal fractionation models, suggesting a discrete mantle source for the carbonatite.

Alkaline fuel cells (AFC's) using renewable fuels are a developing technology capable of meeting market niches in standby, standalone and distributed power generation. AFC's generate electricity, heat and water using hydrogen and oxygen as fuels. While AFC's have been known and the principles demonstrated for over sixty years, their use has been restricted primarily to space applications. Recent technological developments have seen the cost of AFC stacks fall considerably; this together with several other advantages over competing fuel cell technology, has rekindled interest in commercial systems. The main deterrent to wide spread commercialisation of AFC systems is susceptibility to carbon dioxide (CO2) in atmospheric air used as the oxygen supply. AFC's require a low cost, low energy, continuous scrubbing device to reduce CO2 in air from approximately 380 parts per million (ppm) atmospheric concentration to below 50 ppm. Current technology to overcome this problem, a solid expendable absorbent called soda lime, is not viable for commercial systems. The project scope included concept generation of a device to remove CO2 from air, the development of a CO2 measurement technique, investigation of chemistry and flow phenomena to determine design relations, and product design and embodiment. The scrubber system conceived specifically for AFC systems uses the temperature swing chemistry of a liquid chemical absorbent, monoethanolamine, and a packed bubble column apparatus to provide intimate gas-liquid interaction. Prototype development proved the Carbon Dioxide Continuous Scrubber (CDOCS) concept and a Patent Cooperation Treaty (PCT) patent was granted, followed by a full American patent. A gas chromatographic measurement technique was developed to measure low ppm concentration CO2 in air, enabling regular monitoring of scrubbed gas. Carbon dioxide was separated from a small sample of scrubbed air by chromatographic columns, and the gases analysed with a thermal conductivity detector. The GC system was capable of measuring to 10 ppm with good resolution and accuracy. Experimental studies were carried out to characterise the flow dynamics and absorption phenomena in the packed bubble column absorber. The relationship between absorption performance and gas-liquid contact time, an important operating parameter for use with AFC's, was theoretically determined and later confirmed by experiment. The regeneration process was studied and the optimal regenerator design determined to be second, smaller packed bubble column. Experiments were conducted to establish design relations for regeneration temperature, flush gas flow rate and the effect of multiple regeneration cycles. A prototype CDOCS system was built to enable experimental characterisation of scrubbing performance as a function of primary design and operating parameters including liquid depth, regenerator operating temperature and solution composition. This resulted in a good understanding of the system, and an optimised experimental run was performed for cost and performance comparison to existing scrubbing technology. The CDOCS was capable of reducing CO2 in air from 380 to 80 ppm for thirty days, providing low cost, low maintenance scrubbing compared to soda lime. The capital cost of the CDOCS is considerably more than for soda lime scrubbers, and the penalty for extended operation is parasitic power consumption by the CDOCS system totalling less than 7% of fuel cell output. It is suggested that a combination of the two technologies be used initially to provide effective, low cost scrubbing for AFC and CDOCS co-development. Future work on the CDOCS project should include reduction of chemical vapour carry over to the fuel cell, followed by integration with an AFC system. This would allow further development, refinement and design for production to reduce capital cost.

There have been many studies in the energy field to achieve different goals such as energy security, energy independence and production of cheap energy. The consensus of the general population is that renewable energy sources can be used on a short-term basis to compensate for the energy requirement of the world. However, the prediction is that fossil fuels will be used to provide the majority of energy requirements in the world at least on a short-term basis. Coal is one of the major fossil fuels and will be used for a long time because there are large coal reservoirs in the world and many products such as hydrogen, ammonia, and diesel can be produced using coal. In the present study, the performance of a clean energy system that combines the coal gasification and alkaline water electrolyzer concepts to produce hydrogen is evaluated through thermodynamic modeling and simulations. A parametric study is conducted to determine the effect of water ratio in coal slurry, gasifier temperature, effectiveness of carbon dioxide removal, and hydrogen recovery efficiency of the pressure swing adsorption unit on the system hydrogen production. In addition, the effects of different types of coals on the hydrogen production are estimated. The exergy efficiency and exergy destruction in each system component are also evaluated. Although this system produces hydrogen from coal, the greenhouse gases emitted from this system are fairly low.