Thesis (Ph. D.)--University of Wisconsin, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 114-120). Also available in electronic version.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 96-105). Also available in electronic version.

Thesis (M.S.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 146 - 153). Also available for download via the World Wide Web; free to University of Oregon users.

Sewage sludge is currently being disposed by spreading it out on fields, an action that recycles important nutrients such as phosphorus, but also leads to heavy metal contamination. With impeding regulation changes, possibly making it harder or impossible to keep current practice, waste water treatment plants are reviewing their options. One solution could be mono-incineration with phosphorus recovery. However, to make the sludge have a heating value high enough to avoid support fuel it needs to be thermally dried, which requires large amounts of heat. Moreover, large investments would have to be made, creating a more complex system than the current one. Industrial symbiosis could be the solution for making it both more economically and environmentally sustainable and possible, as it is possible to utilise waste heat for the drying, and collaborating with a waste incineration company to incinerate the sludge. Setting up an industrial symbiosis exchange is not always simple; knowing who benefits from what, and who should pay for what investment can be complicated. Moreover, it is often assumed that industrial symbiosis exchanges are environmentally sustainable, but it is not always the case. To better understand how costs should be allocated, and how exchanges should look to be both economically and environmentally sustainable, the methods life cycle analysis (LCA) and life cycle cost analysis (LCC) are suitable to use, as they allow a full view of the system, which can be broken down into different processes. The aim of this study is to see how LCA and LCC can be used on a planned symbiosis project to assess environmental and economical impacts. The results that were found was that using waste heat instead of primary produced heat was not necessarily better, both economically and environmentally in the categories acidification, eutrophication, and global warming potential. If the drying could take place solely during warmer months, through use of storage, then the heat could be produced through waste incineration, creating electricity to sell and replace marginal electricity. There was no clear cut answer to which scenario was better of the thirteen looked at in this study, as different scenarios were better in different categories, which proved the necessity of doing an LCA and a LCC, or similar methods. Moreover, the larger investments were not always the most profitable, even in the best economical scenario, showing the risk of unequal cost distribution. Similarly, the best scenario to avoid global warming potential involved using storage of dried sludge, increasing emissions for the one responsible for the storage, whilst decreasing emissions for incineration substantially. In summary, performing a LCA and a LCC on a planned symbiosis exchange can both show how different choices affect different categories, and help mitigate risks of uneven distribution of both costs and emissions.

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No. of bitstreams: 0 Previous issue date: 2013-02-22Bitstream added on 2014-06-13T19:17:21Z : No. of bitstreams: 1 dare_d_me_araiq_parcial.pdf: 1084104 bytes, checksum: 94d24f977a25928697dd7e3983cd58bc (MD5) Bitstreams deleted on 2014-10-03T16:24:33Z: dare_d_me_araiq_parcial.pdf,Bitstream added on 2014-10-03T16:27:32Z : No. of bitstreams: 2 dare_d_me_araiq_parcial.pdf.txt: 50989 bytes, checksum: 59d01eea3a1cb68242484dce445c1d70 (MD5) 000718986.pdf: 3623967 bytes, checksum: 1a5bc694099e02825cf23b2513ecd0f6 (MD5) Bitstreams deleted on 2014-10-03T16:33:10Z: 000718986.pdf,Bitstream added on 2014-10-03T16:43:24Z : No. of bitstreams: 2 dare_d_me_araiq_parcial.pdf.txt: 50989 bytes, checksum: 59d01eea3a1cb68242484dce445c1d70 (MD5) 000718986.pdf: 3623967 bytes, checksum: 1a5bc694099e02825cf23b2513ecd0f6 (MD5) Bitstreams deleted on 2014-10-03T16:48:50Z: 000718986.pdf,Bitstream added on 2014-10-03T16:49:43Z : No. of bitstreams: 1 000718986.pdf: 3623967 bytes, checksum: 1a5bc694099e02825cf23b2513ecd0f6 (MD5) Bitstreams deleted on 2014-10-27T11:46:59Z: 000718986.pdf,Bitstream added on 2014-10-27T11:48:01Z : No. of bitstreams: 1 000718986.pdf: 3623967 bytes, checksum: 1a5bc694099e02825cf23b2513ecd0f6 (MD5) Bitstreams deleted on 2015-02-27T13:20:32Z: 000718986.pdf,Bitstream added on 2015-02-27T13:21:09Z : No. of bitstreams: 1 000718986.pdf: 3601693 bytes, checksum: a1d7686e4bcd79afb4ce00bd5d120359 (MD5) / Com a crescente preocupação em preservação do meio ambiente e qualidade de vida da população, observa-se um aumento de 95% na quantidade de esgoto tratado no Brasil entre 2000 e 2008. Entretanto, tal evento acarreta na geração de um resíduo denominado lodo de esgoto que é geralmente disposto em aterros sanitários licenciados para este fim. A problemática atual é o fato de que tais aterros já não comportam mais tanto lodo, e é necessária uma alternativa viável de descarte desse resíduo. Para tanto, torna-se imprescindível a caracterização química e comportamento térmico do lodo de esgoto para futuros estudos de reaproveitamento e alocação. Neste estudo, apresentam-se a caracterização química e estudo de decomposição térmica dos lodos das estações de tratamento das cidades de Jaú e São Carlos, ambas no estado de São Paulo. As amostras foram coletadas e tratadas de acordo com cada técnica de análise. O lodo de Jáu apresentou 70% de sua massa de matéria orgânica, enquanto que o lodo de São Carlos apresentou 55%, segundo a análise termogravimétrica. A presença de matéria orgânica nos lodos foi confirmada através das técnicas de demanda química de oxigênio, difratometria de Raios-X e espectroscopia na região do infravermelho. Houve diferença no tamanho de partículas dos lodos, enquanto Jaú apresentou partículas maiores, com cerca de 860nm, São Carlos possui partículas em torno de 310nm. A partir da análise de espectroscopia de absorção atômica, obteve-se a concentração de metais nos lodos e observou-se que esta encontra-se dentro do limite máximo permitido pela legislação vigente no Brasil para reuso como fertilizante agrícola, de acordo somente com este parâmetro. Entretanto, a análise de compostos orgânicos através da cromatografia gasosa acoplada a espectrometria de... / With the growing concern for environmental preservation and quality of life, there is increase of 95% in the amount of treated sewage in Brazil between 2000 and 2008. However, it leads in the generation of a residue named sewage sludge which is generally disposed in sanitary landfills licensed to this application. The current problem is the fact of such landfills no longer can storage much more sludge, and it is required a viable alternative for disposal of this waste. Therefore, chemical characterization and thermal behavior of sewage sludge becomes essential for posterior reuse studies and storage. This study presents the chemical characterization and study of thermal decomposition of sewage sludge from treatment plants of the cities of São Carlos and Jaú, both in the São Paulo state. The samples were collected and handled according to each analysis technique requirements. The amount of organic matter, in mass fraction, in the sludge of Jau was 70%, while the sludge of São Carlos was 55%, according to the thermal analysis. The presence of organic matter in the sludge was confirmed by the techniques of chemical oxygen demand, X-ray diffraction and infrared spectroscopy. The size of the sludge particles of Jaú was around 860nm, while the sludge of São Carlos was around 310nm. The analysis of atomic absorption spectroscopy showed that the concentrations of metals in the sludge samples were according the Brazilian law for reuse as agricultural fertilizer, according only to this parameter. However, the analysis of organic compounds by gas chromatography mass spectrometry indicated the presence of numerous compounds which are not cited in the law and are potentially harmful to the environment. The kinetic evaluation showed the effect of kinetics compensation on the reaction of degradation of organic matter... (Complete abstract click electronic access below)

Municipal sewage sludge is used as source of plant nutrients world wide for agriculture. However, many countries do not make full use of this opportunity. A lack of local knowledge about the benefits and disadvantages of sludge contributes to this low utilisation. For instance, only 28% of the sludge produced in South Africa is beneficially utilized on agricultural lands. The overall objectives of this study were 1) to determine responsible sludge loading rates for a range of cropping systems 2) to investigate the agronomic benefits and sustainability of using municipal sludge according to crop N demand, and 3) to develop a tool to enable extrapolation of these results to other regions (soils, climates) and other cropping systems. Field experiments were conducted on a wide range of cropping systems including dryland maize, irrigated maize-oat rotation, dryland pasture, and turfgrass sod production. An 8 Mg ha-1 control (South African old annual upper limit norm) was compared with sludge rates of 0, 4, and 16 Mg ha-1 for the agronomic crops and dryland pasture. Under the turfgrass sod production, the aim was to export large volumes of sludge with the sod without compromising the environment. Therefore, an 8 Mg ha-1 control treatment was compared with sludge rates of 33, 67, and 100 Mg ha-1 which are equivalent to depths of 5, 10, and 15 mm sludge, respectively. Doubling of the old annual upper limit significantly increased grain and forage yield of both the dryland maize and the irrigated maize-oat rotation. This rate also improved weeping lovegrass hay yield, water use efficiency and crude protein content. Residual nitrate in the soil profile after harvest, and solution samples collected from wetting front detectors were used as indicators of groundwater pollution through nitrate leaching in the medium term. For the irrigated maize-oat rotation and dryland pasture, a low leaching risk was indicated even at high sludge loading rates of 16 Mg ha-1 in this clay loam soil. In contrast, residual nitrate for similar sludge rates under dryland maize cropping did reveal the potential for pollution through leaching. Sludge loading at all rates resulted in the accumulation of total P and loading rates of 16 Mg ha-1 increased Bray-1P in all agronomic and pasture cropping systems. In the case of turfgrass for sod production, sludge loading rates up to 67 Mg ha-1 significantly improved turfgrass establishment rate and colour. The ability of sods to remain intact during handling and transportation improved as the sludge loading rate increased to 33 Mg ha-1, but deteriorated at higher rates. A sludge loading rate of 100 Mg ha-1 was needed to eliminate soil loss at harvest, but this rate was associated with unacceptably high N leaching losses and poor sod strength. The variation in sludge quality, crop nutrient removal across a range of cropping systems, and seasons indicates that a dynamic, mechanistic decision support tool is needed to estimate responsible sludge loading rates. A mechanistic N module was adapted and incorporated into an existing soil water balance/crop growth model (SWB). The model was calibrated with statistically acceptable accuracy for dryland maize, irrigated maize-oat rotation, and dryland pasture. The model was tested against independent data sets and was able to predict the measured variables of interest with acceptable accuracy for dryland maize, irrigated maize and oats. For dryland pasture, the model predicted similar variables of interest with lower accuracy for medium-term simulations, but this improved with updating the profile water content after every hay cut. The ideal sludge loading rate to satisfy crop N demand is dynamic and should be adjusted according to cropping systems, seasonal rainfall variability, sludge N concentration, and sludge application strategy (N or P based). The ultimate cumulative sludge loading of an area will depend on the accumulation of total and Bray-1P, and the risk this poses for pollution, as long as the risk from other pollutants remains minimal. The SWB model shows promise as a decision support tool for sludge management in agricultural lands. / Thesis (PhD)--University of Pretoria, 2010. / Plant Production and Soil Science / unrestricted

Due to environmental pollution caused by acid mine drainage (AMD), the Department of Water Affairs has developed a National Water Bill for managing and controlling the water environment to prevent AMD pollution. The application of sulphate reducing bacteria have been demonstrated for the treatment of AMD. However, the scale-up application of this technology ultimately depends on the cost and availability of a carbon source. This study evaluated the use of sewage sludge to provide a carbon source for sulphate reduction in synthetic drainage wastewaters. The demonstration of this process in a laboratory-scale reactor proved that sewage sludge could provide a useful model and viable carbon source for evaluation of sulphate reduction as a process for treating AMD. Since sewage sludge is a complex carbon source, hydrolysis reactions controlling the anaerobic digestion of particulate substrate from this medium were optimized by evaluating the effect of pH on hydrolysis. Controlled and uncontrolled pH studies were conducted using a three stage mixed anaerobic reactor. Analysis of the degradation behaviour of the three important organic classes (carbohydrate, proteins and lipids) revealed that each class followed an indvidual trend with respect to pH changes. In addition, the solubilization of organic particulate carbon was also shown to be a function of pH. The hydrolysis pattern of organic substrate and COD solublization was induced at pH 6.5 rather than at high pH values (7.5 and 8.5). The biodegradation activity of sewage sludge was characterized by the API-ZYM1N test system to provide rapid semiquantitative information on the activity of hydrolytic enzymes associated with the degradation of carbohydrates, lipids, proteins and nucleic acids. A wide range of enzyme activities with phosphatases, aminopeptidases, and glucosyl hydralases dominating were displayed. The pattern of substrate hydrolysis correlated to the degradation efficiency of each organic class as a function of pH. The evaluation of scale-up application for sulphate reduction utilizing sewage sludge as a carbon source demonstrated that large water volume flows could possibly be treated with this cost-effective technology. Generation of alkalinity and sulphide in this medium was shown to be successful in the removal of heavy metals by precipitation. The use of this technology coupled to reduced cost involved showed that biological sulphate reduction utilizing hydrolysates of complex organic particulate from sewage sludge ss a carbon source has a potential scale-up application for the treatment of AMD.

Pilot-scale ambient and low temperature research into the enhancement of aerobic digestion of waste activated sludge, through control of mixed liquor pH (MLpH), was performed using an extended aeration and a high rate waste sludge. To offset MLpH decreases encountered during nitrification, Ca(OH)₂ and NaHCO₃ were used to control MLpH in the series pH 6, 7 and 8. The performance and behaviour of the digesters, under both controlled and uncontrolled MLpH conditions, were monitored through parameters related to volatile mass reduction, sludge mass metabolism, quality of digested end-product and soluble characteristics of the digester effluent. Volatile mass reduction was significantly affected by MLpH control, under certain conditions. Improvements in reduction performance of >100% over the uncontrolled condition were noted, depending on sludge origin; however, it was concluded that only certain temperature ranges should be targeted for the most effective use of MLpH control, since use of MLpH control in ranges wherein little improvement would be realized was felt to be uneconomical. Analysis of volatile mass reduction rates, based on a series of 1 day batch conditions (necessitated by the reactor flow scheme and the variability of the digestion process), demonstrated that reactor performance oscillated around a mean performance value; MLpH control acted to reduce these oscillations, such that the digesters performed closer to the mean value more of the time. Temperature sensitivity coefficients were quite variable, and a single value did not describe all situations. It was proposed that θ was influenced by digestion system, operating temperature, sludge type and MLpH level. The use of this coefficient for determining the operating ranges most suitable for MLpH control was advanced. The fate of the nutrients nitrogen and phosphorus were greatly influenced by MLpH control. The use of Ca(OH)₂ resulted in less release of phosphorus from the solid phase, with subsequently low effluent PO₄-P concentrations in the neutral MLpH range. The drawback of this reaction was found to be the production of inert inorganic sludge solids, thereby illustrating the need for a trade-off between the various benefits and drawbacks of the enhanced digestion process. Nitrification proceeded at all temperatures, and in conditions previously thought to be inhibitory to the chemolithotrophic organisms. Digester effluent quality was improved through MLpH control, but substantial concentrations of NOx-N were observed under some conditions. Based on direct comparisons with previous lab-scale research, it was concluded that the enhancement process had very good potential for implementation at the full-scale level, either for the improvement of existing underdesigned processes, or for the initial design of more efficient aerobic digestion facilities. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The potential of enhancing lipid accumulation in municipal sewage activated sludge via fermentation of lignocellulose biomass hydrolyzate was investigated. The overall objective was to increase the levels of feedstock lipids in the activated sludge biomass and increase its biodiesel yield via in situ or ex situ transesterification; and improve its cost competitiveness as an abundant feedstock source for biofuels production. To reduce production costs and maintain environmental sustainability, influent wastewater and waste lignocellulose biomass hydrolyzate were used as cultivation media and substrate, respectively. However, lignocellulose hydrolyzates also contain degradation by-products such as furfural and acetic acid that are known to exert inhibitory effects on microorganisms; hence their effects on the fermentative performance of activated sludge were investigated and fermentation strategies were proposed and evaluated to counteract the microbial toxicity of these compounds. The utilization rate and efficiency of xylose by activated sludge microorganisms for lipid production was also evaluated as pentose sugars such as xylose usually constitute a major percentage of lignocellulose hydrolyzates. Furthermore, variations in the population profile of activated sludge microbiota were determined via 16S rRNA sequence analysis to determine the effect of sugar fermentation at different initial conditions. Results show that activated sludge lipid contents and biodiesel yield could be enhanced by fermentation of sugars at a high initial C:N ratio (70:1). Furfural was found to be highly inhibitory to microbial growth and lipid accumulation while high initial acetic acid concentrations enhanced biomass production but not lipid formation. Xylose was also utilized more efficiently than glucose by the activated sludge microorganisms for biomass and lipid production albeit at relatively slower rates; hence sugar mixtures derived from lignocellulose could be utilized for the process. Semicontinuous and continuous fermentation modes were proposed and evaluated as strategies to reduce inhibitory effect of furfural and acetic acid and improve lipid productivity, but the lack of nutrient supplementation prevented the cultures from sustaining microbial growth and lipid production, leading to cell death and washout. Finally, the reduction in the diversity of the activated sludge microbiota could point to specific microbial strains that are mainly responsible for lipid accumulation.