Orientadores: Theo Guenter Kieckbusch, Koichi Fujie / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Quimica / Made available in DSpace on 2018-08-04T03:36:42Z (GMT). No. of bitstreams: 1 Haraguchi_LilianHiromi_M.pdf: 2787215 bytes, checksum: b71f02a7f8c97e582d66c8c4ca3c8bf8 (MD5) Previous issue date: 2005 / Resumo: O controle do lodo em excesso, proveniente dos processos de tratamento de águas residuais industrial e doméstica é, cada vez mais, um assunto de considerável preocupação, pois o descarte destes resíduos pode causar sérios danos ao meio ambiente. Em vista disto, o desenvolvimento de novas tecnologias que permitam uma diminuição na quantidade de lodo produzido torna-se indispensável. Um outro problema encontrado no tratamento de águas residuais é o descarte de alguns nutrientes provenientes do processo, como o fosfato, em cursos d¿água, o que tem aumentado a eutrofização em rios. Um processo chamado Remoção Biológica Aprimorada de Fosfato ¿ EBPR (Enhanced Biological Phosphate Removal), é, atualmente, considerado um dos meios mais econômicos para remoção de fosfato. O presente trabalho teve como objetivo investigar a viabilidade técnica de tratar o lodo em excesso em condições sub e supercríticas da água e reutiliza-lo como fonte de carbono biodegradável no processo EBPR. Lodo em excesso de uma indústria de processamento de peixes (Toyohasshi ¿ Japão) foi submetido às reações hidrotérmicas em um reator em batelada, a uma faixa de temperatura de 200 '400 GRAUS¿C, pressões variando de 1,8 a 30 Mpa e tempo de reação de 10 min. Ensaios de liberação de fosfato foram conduzidos com o objetivo de analisar a capacidade dos microorganismos em liberar fosfato intracelular em meio anaeróbio, utilizando o lodo tratado como fonte de carbono... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: the control of excess sludge produced in the industrial and domestic wastewater treatment plants has been a matter of considerable concern. Discharge of excess sludge poses significant risks to the environment and the development of new technologies that are able to suppress the pollution have challenged many researches. On the other hand, the release of some nutrients like phosphorus in wastewater streams increases the eutrophication problem in many rivers throughout the world with the consequent growth of algae induced by high levels of phosphate. Enhanced Biological Phosphate Removal (EBPR) process has been currently considered one of the most economical ways to remove phosphate from the wastewaters. The objective of this work is to investigate the feasibility of reusing excess sludge from a fish processing industry located in Japan was treated by hydrothermal reactions, at reaction temperature ranging from 200 to '400 DEGREES¿, pressure of 1,8 to 30 MPa and fixed reaction time of 10 min. Experiments on phosphorus release under anaerobic conditions were also carried out using the treated excess sludge as carbon source. For the hydrothermal conditions tested, the results showed that the solubilization and the biodegradability were improved as evidenced by its content change after hydrothermal reactions... Note: The complete abstract is available with the full electronic digital thesis or dissertations / Mestrado / Engenharia de Processos / Mestre em Engenharia Química

This research aimed to firstly confirm the hypothesis that the current management of sewage sludge generated during the treatment of wastewater in the Eastern Cape Province of South Africa is poor and, as such, this material poses a threat to local environmental and human health. Secondly, through a rational design approach, the current research also aimed to design and assess the suitability of a novel integrated process incorporating appropriate technologies for improved sewage sludge management. The lack of an appropriate tool for the assessment of the integrated process necessitated the development of an appropriate technology assessment (TA) methodology based on environmental, technical, social and economic criteria. A combination of informal participatory methods such as semi-structured interviews and formal research methods including questionnaires, risk assessment exercises and laboratory analyses were used. Based on the above it was estimated that 116 tons dry sludge were generated in the province per day and that the concentration of heavy metals present in the sludge was generally within the limits for reuse on agricultural land. Furthermore the sludge from all sample sewage treatment works (STWs) was found to be free of any detectable pathogens. Despite the above, a preliminary risk assessment and chemical analysis revealed that existing sludge management practices at sample STWs posed a threat to the environment, particularly to water resources and exacerbated the problems associated with the discharge of poorly treated municipal wastewater. The root causes of the poor sludge management were considered to be a lack of non-regulatory incentives and financial resources. Highly integrated ecologically engineered systems were thought to offer a solution to the dual problem of poor sludge management and municipal effluent treatment, while providing necessary economic incentives. To facilitate the design of a system appropriate to local conditions, it was necessary to first develop a rational design methodology, which incorporated a detailed TA step. The result of the design process was an Integrated Waste Beneficiation Facility (IWBF) that incorporated a number of process units comprised of appropriate technologies including composting, vermicomposting, algal ponding technology and aquaculture. A detailed TA indicated that the benefits of the proposed IWBF would, at the majority of sample sites, outweigh the potential negative impacts and it was thus recommended that investigations should continue on pilot-scale facilities. Furthermore, although the proposed TA based on four sustainability criteria categories was thought to provide a more accurate assessment of the true sustainability of a technology, the acquisition of information was problematic highlighting the need to re-think current TA methodologies and to address associated constraints allowing the tool to be used and fully comprehensive.

Submitted in fulfilment of the requirements for the Degree of Master of Engineering, Durban University of Technology, 2017. / In this research, the woven fibre microfiltration (WFMF) fabric which is produced locally in South Africa is used as a membrane material. It is cheaper in price in comparison with the current commercial membrane materials that are in use. The WFMF is also more robust when compared with the commercial membrane materials thus is able to withstand harsh working conditions. From previous studies on the WFMF, it has been shown that it can be used as a membrane material without any compromise to permeate quality. This research seeks to optimize the working conditions of this membrane material (WFMF) with an aim of achieving lower running costs and better anti fouling strategies in comparison to the commercial MBRs. The objectives and aims of this research was to come up with a MBR system whose running cost is lower than that for the commercial systems, which can be adapted for use in any environment, especially in the hardship regions where its robustness would be an added advantage. The performance of the WFMF submerged MBR was also optimised including antifouling operating regimes. This study was done in a pilot plant that was set up at Veolia wastewater treatment plant, Durban Metro Southern Works. The feed water for the pilot plant was pumped from the return activated sludge mixing chamber by means of a submersible pump. The MLSS concentration of the feed water was about 12 g/l. The various investigations that were conducted in the course of this research included the effect of spacing between membrane modules, relaxation steps and frequencies, evaluation of aeration rates and evaluation of coarse vs. fine bubbles which were all aimed at optimizing the performance of the immersed WFMF MBR. The permeate was checked for turbidity and COD levels to ensure that they were within the accepted water standards. From the experiments it is shown that the critical flux increased with an increase in aeration rate which is in concurrence with the literature and a starting flux of 30 LMH was chosen for the running of the pilot plant for the various experimental runs to be carried out. For the pipe diffuser height effect experimental run, the best results were achieved at a height of 5 cm below the membrane modules and the use of a pipe diffuser gave better results than the use of a disc diffuser. For the membrane module spacing effect the best results were obtained at the smallest possible width i.e. 3.5 mm. The best relaxation step sequence was found to be 9 mins on and 1 min off. COD, turbidity and DO was continuously determined during the course of the experimentation. Further studies should be done on use of the disc diffuser with increased surface area of aeration holes and also hole sizes of smaller diameters to check on its effectiveness as a means of reducing fouling on the membrane surface. / M

High rate algae oxidation ponds (HRAOP) for domestic wastewater treatment generate biosolids that are predominantly microalgae. Consequently, HRAOP biosolids are enriched with minerals, amino acids, nutrients and possibly contain plant growth regulator (PGR)-like substances, which makes HRAOP biosolids attractive as fertiliser or PGR. This study investigated HRAOP biosolids as a starting material for a natural, cost-effective and readily-available eco-friendly organic fertiliser and/or PGRs. Various HRAOP extract formulations were prepared and their effect on plant growth and development was evaluated using selected bioassays. Initial screening included assessing the effect on change in specific leaf area, radish cotyledon expansion as an indicator of PGR-like activity, and seed germination index (GI). More detailed studies on fertiliser efficacy and PGR-like activity utilised bean (Phaseolus vulgaris) and tomato (Solanum lycopersicum) plants. Combined effects of sonicated (S) and 40% v/v methanol (M) extract (5:1 SM) had impressive plant responses, comparable to Hoagland solution (HS). Other potentially fertiliser formulations included 0.5% M, 1% M, 2.5% S and 5% S formulations. The 5:1 SM and 5% S showed greater PGR-like activity, promoting cotyledon expansion by 459 ± 0.02% and 362 ± 0.01%, respectively. GI data showed that none of the formulations negatively impacted germination. Further investigation showed that the 5% S formulation increased leaf length, width and area by 6.69 ± 0.24, 6.21 ± 0.2 mm and 41.55 ± 0.2 mm². All formulated fertiliser extracts had no adverse effect on chlorophyll content and plant nutrient balance as indicated by C:N (8-10:1) ratio. In addition, plants appeared to actively mobilise nutrients to regions where needed as evidenced by a shift in shoot: root ratio depending on C, N and water availability. Furthermore, 5% S caused a 75% increase in tomato productivity and had no effect on bean productivity. Whereas, 5:1 SM and 1% M formulation improved bean pod production by 33.3% and 11%, respectively but did not affect tomato production. Harvest index (HI) however indicated a 3% reduction in tomato productivity with 5:1 SM and little or no enhancement in bean productivity with both 5:1 SM and 5% S treatments. Bean plants treated with 5:1 SM and 5% S produced larger fruits, which could be an indication of the presence of a PGR effect. Overall, HRAOP biosolids extracts prepared and investigated in this study demonstrated both fertiliser characteristics and PGR-like activity with performances comparable and in some cases exceeding that of commercial products. However additional research is needed to confirm presence of PGR-like activities and fertiliser efficacy.

M.Sc. (Chemistry) / Prosperity for South Africa depends on the sound management and utilization of many resources, with water playing a crucial role. Located largely in a semi-arid part of the world, South Africa’s water resources are, in global terms, scarce and extremely limited. A key environmental problem facing South Africa is water pollution. This arises from many sources, including mining and industrial effluents, and runoff of biocides, nutrients and pathogens from agricultural lands, urban areas and informal settlements with poor sanitation. The consequences are often severe, including among other impacts, habitat destruction, reduced oxygen levels, fish kills and loss of human life. Inorganic and organic pollutants as well as microbes are the main constituents of the effluent from the domestic, mining, agriculture, metal electroplating, petrochemical and transport industries. The presence of pollutants in environmental systems is of concern because ultimately, they are incorporated into drinking water and various food chains. Therefore, the overall focus of this study was mainly metals analysis in wastewater systems before and after treatment processes so as to establish the efficiency of the treatment processes....

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This research was prompted by a field study performed at the Celanese Corporation Wastewater Treatment Plant, Narrows, VA., in which calcium chloride addition had improved sludge characteristics that were believed to have deteriorated because of sodium hydroxide additions for pH control. Research objectives were to determine whether the observed improvements during the full-scale plant study were caused by the addition of divalent cations and whether the deterioration of the sludge was due to sodium ion additions. Bench-scale, activated sludge reactors were fed wastewater from the Celanese plant to model plant conditions. Sodium was added in an attempt to cause deterioration of the sludge characteristics. Magnesium and calcium were used as divalent cations to try to improve the sludge characteristics. Results of the study indicated that the magnitude of the effects seen in the full-scale plant study could not be reproduced in the laboratory. Magnesium produced little or no effect on the system and calcium improved the sludge characteristics slightly. Sodium caused deterioration of the sludge but not as dramatically as the full-scale study. This suggested that sodium alone did not adversely affect the sludge but rather, sodium hydroxide might have been combined with organics in the waste which then affected the system. / Master of Science

Currently at the Savannah River Site (SRS), there are fifteen single-shell, 3.6-million liter tanks containing High Level Waste. To close the tanks, the sludge must be removed. Mechanical methods have had limited success. Oxalic acid cleaning is now being considered as a new technology. This research uses sample results and chemical equilibrium software to develop a preferred flowsheet and evaluate the acceptability of the system impacts. Based on modeling and testing, between 246,000 to 511,000 l of 8 wt% oxalic acid were required to dissolve a 9,000 liter Purex sludge heel. For SRS H-Area modified sludge, 322,000 to 511,000 l were required. To restore the pH of the treatment tank slurries, approximately 140,000 to 190,000 l of 50 wt% NaOH or 260,000 to 340,000 l of supernate were required. When developing the flowsheet, there were two primary goals to minimize downstream impacts. The first was to ensure that the Resultant oxalate solids were transferred to DWPF, without being washed. The second was to transfer the remaining soluble sodium oxalates to the evaporator drop tank, so they do not transfer through or precipitate in the evaporator pot. Adiabatic modeling determined the maximum possible temperature to be 73.5°C and the maximum expected temperature to be 64.6°C. At one atmosphere and at 73.5°C, a maximum of 770 l of water vapor was generated, while at 64.6°C a maximum 254 l of carbon dioxide were generated. Although tank wall corrosion was not a concern, because of the large cooling coil surface area, the corrosion induced hydrogen generation rate was calculated to be as high as 10,250 l/hr. Since the minimum tank purge exhaust was assumed to be 5,600 l/hr, the corrosion induced hydrogen generation rate was identified as a potential concern. Excluding corrosion induced hydrogen, trending the behavior of the spiked constituents of concern, and considering conditions necessary for ignition, energetic compounds were shown not to represent an increased risk Based on modeling, about 56,800 l of Resultant oxalates could be added to a washed sludge batch with minimal impact on the number of additional glass canisters produced. For each sludge batch, with 1 to 3 heel dissolutions, about 60,000 kg of sodium oxalate entered the evaporator system, with most collecting in the drop tank, where they will remain until eventual salt heel removal. For each 6,000 kg of sodium oxalate in the drop tank, about 189,000 l of Saltstone feed would eventually be produced. Overall, except for corrosion-induced hydrogen, there were no significant process impacts that would forbid the use of oxalic acid in cleaning High Level Waste tanks. / MATHEMATICAL SCIENCES / M. Tech. (Chemical Engineering)

Thesis (M.Tech.: Chemical Engineering)-Dept. of Chemical Engineering, Durban University of Technology, 2005 1 v. (various pagings) / In bubble-less aeration oxygen diffuses through the membrane in a molecular form and dissolves in the liquid. Oxygen is fed through the lumen side of silicone rubber tube. On the outer surface of the membrane there is a boundary layer that is created by oxygen. This then gets transported to the bulk liquid by convective transport created by water circulation through the pump. The driving force of the convective transport is due to concentration difference between the dissolved oxygen in water and oxygen saturation concentration in water at a particular temperature and pressure. The design of a membrane aerated bioreactor needs an understanding of the factors that govern oxygen mass transfer. It is necessary to know the effects of operating conditions and design configurations. Although various methods of bubble-less aeration have been reported, there still exists a lack of knowledge on the immersed membrane systems. This study is aiming at contributing to the development of an immersed membrane bioreactor using silicone rubber tubular membrane as means of providing oxygen. The secondary objective was to investigate the influence that the operating conditions and module configuration have on the system behaviour. From the experimental study, the characteristic dissolved oxygen -time curve show that there is a saturation limit equivalent to the equilibrium dissolved oxygen concentration, after which there is no increase in dissolved oxygen with time. At ambient conditions the equilibrium dissolved oxygen is approximately 8 mg/L. This is when water is in contact with air at one atmospheric pressure. At the same conditions the equilibrium dissolved oxygen concentration when water is in contact with pure oxygen is approximately 40 mg/L. This is why all the experiments were conducted from 2mg/L dissolved oxygen concentration in water, to enable enough time to reach equilibrium so as to determine mass transfer coefficient. The most important parameters that were investigated to characterise the reactor were, oxygen supply pressure, crossflow velocity, temperature and module orientation. Observations from the experimental study indicated that when the system is controlled by pressure, crossflow does not have a significant effect on mass transfer. When the system is controlled by the convective transport from the membrane surface to the bulk liquid, pressure does not have a significant effect on mass transfer. All four effects that were investigated in the study are discussed.