91 |
The Effects of Physical Stressors on Bacterial Inactivation Rates in BiosolidsO'Shaughnessy, Susan Ann January 2006 (has links)
Sanitation is fundamental to reducing disease and sustaining a high standard of living. The evolution of sewer systems and the modern engineering of wastewater treatment plants work to decrease health risk and manage environmental concerns associated with the reuse and disposal of treated effluent and solid wastes generated as byproducts. The recycling of treated solid wastes (biosolids) continues to be an environmental challenge due to the shear volume produced, and its potentially hazardous composition. Solar drying of biosolids was studied in semi-arid regions as a sustainable method for reducing pathogens. The initial studies were performed with no intervening treatments. Average fecal coliform inactivation rates for digested biosolids during summer experiments were determined to be 0.17 ± 0.03/day⁻¹ and 0.17 ± 0.04/day⁻¹, respectively. Salmonella inactivation rates in aerobically digested biosolids were 0.11 ± 0.08 day⁻¹ and 2.0 ± 2.0 day⁻¹ for aerobically and anaerobically digested biosolids, respectively for the summer seasons. Solar drying during warm dry seasons was effective in reducing pathogens. Microbial testing to verify the quality of biosolids can be expensive. Utilizing a mathematical model to predict pathogen density levels during the solar drying process can minimize such testing. The first order mathematical model, N(t) = N(o) * 10⁻ᵏᵈᵗ where the inactivation constant, k(d), is further defined as a function of moisture (Θ) and temperature (T), i.e. k(d) = f(Θ,T): k(d) = (k₁/( k₁ + Θ) * (T/(k₂-T)) * k₃, k₁ = 0.112, k₂ = -41.88, and k₃ = -0.5357; for all T greater than or equal to 38ºC, T=38°C provided a good estimate of the inactivation rate of fecal coliforms in biosolids. During subsequent field studies, treatments were employed to manage the drying cycle of biosolids - tilling increased the rate of drying, a covered solar drying bed increased the inactivation rate of fecal coliforms by 300%, and an automated rain shield was engineered to limit enteric bacterial regrowth due to rainfall. Finally, since biosolids are to be considered a source of nitrogen when land-applied, temporal samples of biosolids from various solar drying experiments were analyzed to ascertain the levels of NH⁺₄-N and NO⁻₃-N throughout the drying process. Chemical analyses revealed that as much as 34-92% of nitrogen was lost via volatilization during the drying process.
|
92 |
Fixation of Ammonia by soils.Nyborg, M. January 1963 (has links)
In 1917, McBeth (43) found that applied ammonium waa fixed by subsoils. Later workers showed that fixation occurred through entrappment of the ammonium ion in interlattice spaces of certain clay minerals. ln recent years, ammonium fixation by clay minerals has been intensively studied by American investigators. [...]
|
93 |
Investigations of Novel Uses for Boron Compounds in Organic and Inorganic ChemistryLABERGE, VERONIQUE 30 September 2011 (has links)
Herein I describe a model study to determine the feasibility of organic hydride donors as a source of hydride in the regeneration of ammonia borane. Hydride transfer was observed in the model system comprised of Hantzsch ester and several analogues, as the organic hydride donor, and tris(pentafluorophenyl)boron, as the boron-based hydride acceptor akin to BBr3. Side reactions could be minimized by varying the reaction conditions. We determined that a Lewis acid-base adduct was forming between the carbonyls of the donor and the hydride acceptor, that this adduct was dynamic in the case of Hantzsch ester and that it could be inhibited by bulkier ester groups or promoted by reducing the steric bulk at the carbonyl in the case of a methyl ketone. The thermodynamics of the hydride transfer reaction with an N-substituted analogue were probed via variable temperature NMR and compared to two differently substituted analogues.
In addition, the scope of the sp2-sp3 Suzuki-Miyaura cross-coupling previously developed in our lab was extended to include 2-(1,2-diaryl)ethane pinacolborane scaffolds. In order to access this asymmetric scaffold, reaction conditions for the cross-coupling of a primary boronic ester in the presence of a secondary one were developed. Yields achieved for the linear cross-coupling were in the 70 % range and varied from 42 % to 69 % for the secondary position. These latter yields are in the same range as the hydroborated styrene scaffolds described in our first account demonstrating the broad scope of these reaction conditions. / Thesis (Master, Chemistry) -- Queen's University, 2011-09-30 14:43:02.652
|
94 |
Evaluation of nitrogen losses in the form of ammonia from surface applied manureBrunke, Richard R. January 1986 (has links)
No description available.
|
95 |
Removal of ammonia from wastewater by ion exchange in the presence of organic compoundsJorgensen, Tony Charles January 2002 (has links)
The aim of the work described in this thesis was to study the removal of ammonium ions from water by ion exchange. The classical technique is to use biological nitrification and denitrification to convert ammonia into nitrogen gas. Removal by ion exchange offers a number of advantages, such as the ability to handle shock loadings and to polish water to a very high specification. The ion exchanger used in this project was clinoptilolite, a naturally occurring zeolite. Previous research has included characterisation of clinoptilolite, the effect of other common cations on uptake, biological regeneration, and a few other studies. A comparison with other exchangers was also conducted. Much of the available literature is concerned with clinoptilolite and occasionally with mordenite, however modern ion exchangers are polymer based. Two polymeric ion exchangers (Dowex 50w-x8, and Purolite MN500) were evaluated in this project. The main scope of this thesis was to look at the effect that organic pollutants has on ammonium ion removal during ion exchange. The results of batch equilibrations of NH4+ and the three exchanger resins can be seen in chapter 4.0. They show that the presence of an organic compound enhanced the uptake of NH4+ in most cases onto clinoptilolite and Purolite MN500. There was no apparent uptake onto Dowex 50w-x8. Further experiments with a sample of real industrial wastewater (woolscour wastewater) showed varied results, showing that each site should carry out its own pilot scale testing during plant design. Other experimental work showed that the exchanger resins adsorb little or none of the organic compounds in solution. These results can be seen in chapter 5.0. ii Removal of ammonia from wastewater by ion exchange in the presence of organics. Studies in a packed column showed that the presence of organic compounds had little or no effect on NH4+ removal. There was however an increase in capacity after each regeneration of the bed and continued removal after breakthrough. The same results were achieved in the control experiment with no organic compounds present, hence these results are not related to the presence of an organic compound. The presence of NH4+ and various compounds did however provide micro-organisms with substrates from which to grow causing hydraulic difficulties in the column. See chapter 6.0 for these results. The final section of experimental work studied whether the presence of organic compounds changed the rate of uptake of NH4+. The results in chapter 7.0 show that there was no effect on the rate of NH4+ uptake.
|
96 |
Comparative study of ammonia-based clean rail transportation systems for Greater Toronto areaHogerwaard, Janette 01 April 2014 (has links)
Ammonia as a transportation fuel offers a carbon-free, hydrogen rich energy source
that emits no greenhouse gases in combustion, and has no global warming potential.
Furthermore, it may be produced from any renewable energy resource, and is a
strong option for long term sustainability. Ammonia also provides a pathway
towards a hydrogen economy, which is the long term goal for environmental
sustainability.
This thesis investigates the feasibility of integrating ammonia as a combustion
fuel, hydrogen carrier, heat recovery and working fluid, and for indirect engine
cooling, within locomotive propulsion systems for nine novel ammonia-based
configurations. Thermodynamic, environmental, and economic analyses are
conducted for a typical modern diesel-fueled locomotive and the proposed ammonia
configurations. The study comparatively assesses potential long term solutions for
sustainable, clean rail transportation.
From the modeled results, the proposed systems operating with 50% of
required fuel energy replaced by ammonia have a reduction in diesel fuel
consumption from 0.211 kg/s to less than 0.10 kg/s. This is associated with a
reduction in GHG emissions of more than 8 tonnes CO2eq for a typical daily
locomotive duty cycle for commuter operation. Criteria air contaminants are reduced
to below upcoming Tier 3 emission levels for NOx and HC emissions, and meet
current levels for PM emissions. In total, ten locomotive propulsion systems are
investigated including the diesel-fueled locomotive baseline, and the performance
gains are considered against economic factors for fuel and equipment costs in a
comparative assessment.
|
97 |
Simulation of a membrane reactor for ammonia decomposition /Kraisuwansarn, Nichakorn. January 1991 (has links)
Thesis (M.S.)--Oregon State University, 1992. / Typescript (photocopy). Includes bibliographical references (leaves 82-85). Also available on the World Wide Web.
|
98 |
Longitudinal changes in potential toxicity of coalbed natural gas produced water along Beaver Creek in the Powder River Basin, WyomingJohnson, Laurie A. January 2007 (has links)
Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on June 16, 2008). Includes bibliographical references (p. 134-135).
|
99 |
Study of a constrained-film bubble absorber under cycle operating conditions /Cardenas, Ruander. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 195-198). Also available on the World Wide Web.
|
100 |
Ammonia oxidation potential and microbial diversity in sediments from experimental bench-scale oxygen-activated nitrification wetlandsAllen, Jennifer. January 2009 (has links) (PDF)
Thesis (M.S. in civil engineering)--Washington State University, May 2009. / Title from PDF title page (viewed on July 15, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 21-31).
|
Page generated in 0.0327 seconds