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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
511

Modelling of a bioflocculant supported dissolved air flotation system for fats oil and grease laden wastewater pretreatment

Mukandi, Melody January 2017 (has links)
Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017. / In the recent past, the poultry industry in South Africa has grown due to an increased demand of poultry products as a result of population growth and improved living standards. Furthermore, this has led to poultry slaughterhouses generating high strength wastewater which is laden with a high concentration of organic and inorganic pollutants from the slaughtering process and sanitation of equipment and facilities. As a result, South Africa has promulgated restrictions and a set of quality standards for effluent discharged into the environment to minimize ecological degradation and human health impact. Hence, there is a need for improved Poultry Slaughterhouse Wastewater (PSW) pre-treatment prior to either discharge into municipal wastewater treatment plants (WWTP) or on-site secondary treatment processes such as anaerobic digesters. Additionally, amongst the pre-treatment methods for Fats, Oil and Grease (FOG) laden wastewater, flotation remains the most popular with Dissolved Air Flotation (DAF) system being the most applied. However, modelling and optimization of a biological DAF system has never been attempted before in particular for a bioflocculant supported DAF (BioDAF) for PSW pre-treatment. Process modelling and optimization involves process adjustment to optimize influential parameters. In this study, Response Surface Methodology (RSM) was used to develop an empirical model of a BioDAF for pre-treatment of PSW, for which a bioflocculant producer including production conditions, flocculant type and its floc formation mechanism, were identified. Twenty-one (n = 21) microbial strains were isolated from the PSW and their flocculation activity using kaolin clay suspension (4g/L) was quantified, with a mutated Escherichia coli (mE.coli) [accession number LT906474.1], having the highest flocculation activity even in limited nutrient conditions; hence, it was used for further analysis in other experiments. Furthermore, the optimum conditions for bioflocculant production achieved using RSM were pH of 6.5 and 36°C conditions which induced instantaneous bioflocculant production with the highest flocculation activity. The bioflocculant produced by the mE.coli showed the presence of carboxyl/amine, alkyne and hydroxyl functional groups, which was indicative that the bioflocculant contained both polysaccharides and some amino acids.
512

Estudo da migração de radionuclídeos em depósito para fontes seladas tipo poço tubular / Study of radionuclide migration in repository type tubular well for sealed souces deposition

SABBAG, MAURICIO G. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:41:13Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:33Z (GMT). No. of bitstreams: 0 / Visando contribuir com o desenvolvimento de uma metodologia adequada ao Brasil para deposição de fontes seladas fora de uso, o presente estudo avaliou cenários de migração de radionuclídeos para fora de um repositório profundo tipo poço tubular. Considerou-se uma fratura anelar como caminho preferencial de fluxo da água subterrânea, que futuramente adentrará os poços, entrando em contato direto com as fontes. No futuro, fenômenos naturais e ação antrópica poderiam levar à degradação dos materiais que formam as barreiras artificiais do repositório e formar uma via preferencial de transporte e migração dos radioisótopos depositados. Haveria intrusão de água subterrânea e contato com as fontes seladas, corrosão e transporte dos radioisótopos para o ambiente acessível ao homem. A modelagem de transporte considerou percolação de água subterrânea numa fratura causada pelo descolamento entre o tubo de aço e a pasta de cimento, que separa o repositório do meio geológico. Foram simulados cenários de migração e o estudo poderá ser aproveitado na escolha de sítio e de novas técnicas para selagem. Diferentes gradientes hidráulicos e espessuras de fratura, entre outros parâmetros, influirão diretamente no fluxo pela fratura postulada que resultarão em diferentes tempos de trânsito até a biosfera. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
513

A Review of policies for sustainable solid waste management service in Buffalo City Metropolitan Municipality

Qhayi-Shweni, Nokuzola January 2014 (has links)
Waste is not only harmful to the environment alone but it is also a threat to human health and as such its proper management becomes critical. This study which adopted a qualitative approach focused on the review of policies for sustainable solid waste management service in Buffalo City Metropolitan Municipality in an effort to seek what the municipality’s Solid Waste Department should consider in ensuring that all the communities live in a litter free, clean and healthy environment, and ensure that such a service is received by all communities within its jurisdiction. The most sustainable solid waste management strategy would be to adopt the solid waste hierarchy of promoting waste minimisation, re-use, recycling, waste treatment and disposal as the last resort.
514

Fungal remediation of winery and distillery wastewaters using Trametes pubescens MB 89 and the enhanced production of a high-value enzyme therein

Strong, Peter James January 2008 (has links)
In this study white-rot fungi were investigated for their efficiency at distillery wastewater remediation and the production of laccase as a valuable by-product. Distillery wastewaters are high in organic load and low in pH. The presence of phenolic compounds can lead to extremely colour-rich wastewaters and can be toxic to microorganisms. The presence of the inorganic ions may also affect biological treatment. White-rot fungi are unique among eukaryotic or prokaryotic microbes in possessing powerful oxidative enzyme systems that can degrade lignin to carbon dioxide. These ligninolytic enzymes, such as lignin peroxidase, manganese peroxidase and laccase, are capable of degrading a vast range of toxic, recalcitrant environmental pollutants and this makes the white-rot fungi strong candidates for the bioremediation of polluted soils and waters. The laccase enzyme alone has shown remediation potential in wastewaters such as beer production effluent, olive mill wastewater, alcohol distillery wastes, dye-containing wastewaters from the textile industry as well as wastewaters from the paper and pulp industry. It has been shown to be capable of remediating soils and waters polluted with chlorinated phenolic compounds, polyaromatic hydrocarbons, nitrosubstituted compounds and fungicides, herbicides and insecticides.
515

Application of acidogenic solids removal in the biological treatment of wastewater from a Bagasse based pulp and paper mill

Hunt, Neil Adrian 27 October 2005 (has links)
No abstract available. / Dissertation (MSc (Water Utilization))--University of Pretoria, 2006. / Chemical Engineering / unrestricted
516

Groundwater contamination from waste-management sites : the interaction between risk-based engineering design and regulatory policy

Massmann, Joel Warren January 1987 (has links)
This dissertation puts in place a risk-cost-benefit analysis for waste management facilities that explicitly recognizes the adversarial relationship that exists in a regulated market economy between the owner-operator of the facility and the government regulatory agency under whose terms the facility must be licensed. The risk-cost-benefit analysis is set up from the perspective of the owner-operator. It can be used directly by the owner-operator to assess alternative design strategies. It can also be used by the regulatory agency to assess alternative regulatory policies, but only in an indirect manner, by examining the response of an owner-operator to the stimuli of various policies. The objective function is written in terms of a discounted stream of benefits, costs, and risks over an engineering time horizon. Benefits are in terms of revenues for services provided; costs are those of construction and operation of the facility. Risk is defined as the expected cost associated with failure, with failure defined as a groundwater contamination event that violates the licensing requirements set forth by the regulatory agency. Failure requires a breach of the containment structure and contaminant migration through the hydrogeological environment to a compliance surface. Reliability theory is used to estimate the probability of breaching and Monte Carlo finite-element simulations are used to simulate advective contaminant transport. The hydraulic conductivity values in the hydrogeological environment are defined stochastically. The probability of failure is reduced by the presence of a monitoring network established by the owner-operator. The level of reduction in the probability of failure can be calculated from the stochastic contaminant transport simulations. While the framework is quite general, the development in this dissertation is specifically suited for a landfill in which the primary design feature is one or more synthetic liners and in which contamination is brought about by the release of a single, nonreactive species in an advective, steady-state, horizontal flow field. The risk cost benefit analysis is applied to 1) an assessment of the relative worth of alternative containment-construction activities, site-investigation activities, and monitoring activities available to the owner-operator, 2) an assessment of alternative policy options available to the regulatory agency, and 3) two case histories. Sensitivity analyses designed to address the first issue show that the allocation of resources by the owner-operator is sensitive to the stochastic parameters that describe the hydraulic conductivity field at a site. For the cases analyzed, the installation of a dense monitoring network is of less value to the owner-operator than a more conservative containment design. Sensitivity analyses designed to address the second issue suggest that from a regulatory perspective, design standards should be more effective than performance standards in reducing risk, and design specifications on the containment structure should be more effective than those on the monitoring network. Performance bonds posted before construction have a greater potential to influence design than prospective penalties to be imposed at the time of failure. Sitting on low-conductivity deposits is a more effective method of risk reduction than any form of regulatory influence. Results of the case histories indicate that the methodology can be successfully applied at field sites, and that the risks associated with groundwater contamination may be small when compared to the owner-operators' benefits and costs. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
517

Kraft mill effluent and the Pacific oyster

Pedlow, Jane C. January 1974 (has links)
Studies were undertaken to determine the effect of Kraft mill effluent (KME) on a representative species of the aquatic environment. By transplanting a population of Pacific oysters (Crassostrea gigas) to the Port Mellon area (the site of a Kraft mill), the effect of varying concentrations (on a distance from the mill basis) of the pulp mill waste was monitored in terms of changes in shell dimension, body mass (meat) weight, visual observation of the oysters' physiological state and oyster mortality. A seasonal hydrographic survey was conducted at three regions within the study area to monitor changes in water quality imposed by the effluent. In the areas of effluent imposition (oyster stations 1, 2 and 3) the oysters decreased or showed little gain in shell dimension. The body mass of those oysters nearest the mill outfall began to decline (on a weight basis) shortly after placement. At Station 2 and 3 the deterioration in body mass due to changes in water quality began a short time after the decline at Station 1. Changes in the physiological state of the oyster expressed as a darkening of the gills and mantle edge and variations in body mass texture, can be correlated to an oyster's distance from the mill for each collection timei A mortality rate was calculated at each station for all collection times. The mortality rates at Station 1 (100% in 12 months), Station 2 (50% in 20 months), and Station 3 (20% in 24 months) were extensive and proportional to effluent levels. Several of the changes in water quality (increased temperature, reduced salinities, low oxygen contents, variable pH, dissolved and particulated organic matter and chemical additions) imposed by the effluent were individually tested as the major cause of oyster deterioration. Firstly, the critical oxygen tension (the P02 where V02 declines below the routine rate) was determined as 40 mmHg. Correlating this to the range of 02 levels at each station during a tidal cycle, the oxygen demand of the effluent was not considered as a major cause of oyster mortality. A range of filtered, neutralized (pH 7.0 at 22°C) and aerated percentage KME/volume (0-50%) test solutions were monitored in terms of their effect on the percentage time of shell closure. In these experiments percentages above 20 greatly increased the time of shell closure. The effect of shell closure on oysters was tested by continual (up to 28 days) periods of air exposure. In these experiments the P02, zC02 and pH of the pallial fluid was monitored (from time 0 to 28 days) to determine if anaerobic metabolism was undertaken and if it was, the time span of anaerobic life in juvenile oysters. Anaerobic metabolism was concluded to maintain life in juvenile oysters for 22 days. These results were consistent with the hypothesis that KME is deleterious to oyster populations. At high concentrations of effluent the duration of shell closure is extensive such that an anaerobic death results. At lower concentrations the effluent imposed changes in water quality are responsible for the gradual decline in oyster well-being. / Science, Faculty of / Zoology, Department of / Graduate
518

A comparative study of municipal waste disposal practices and management in the Breede River District Council and the Cape Metropolitan Area

Frantz, Amanda. January 2006 (has links)
Magister Artium - MA / Solid waste management is a phenomenon that has been researched for many years. With the development of industries and commerce, waste inputs into waste management programs are crucial, since these are the sectors responsible for the generation of waste and thus the inputs are invaluable when programs are formulated. In order to develop effective waste management strategies, it is important to identify the source of waste generation and the processes that must be followed to minimize waste. The objective of this research was to follow waste from generation to ultimate disposal and to case study why and how differences in waste disposal practices occur in the Breede River District (BRD) and the Cape Metropolitan Area (CMA). / South Africa
519

Selection of disposal method for nuclear spent fuel: a plan for the application of the systems engineering process

Min, Bryan B. 16 February 2010 (has links)
Master of Science
520

Development of a quantitative method for functional gene detection in pulp and paper wastewater treatment systems

Neufeld, Josh D. January 2000 (has links)
No description available.

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