A 2000 mm long saturated laboratory soil column was used to simulate soil aquifer treatment under saturated conditions to assess the removal of chemical and biochemical oxygen demand (COD and BOD), dissolved organic carbon (DOC), nitrogen and phosphate, using high strength artificial wastewater. The removal rates were determined under a combination of constant hydraulic loading rates (HLR) and variable COD concentrations as well as variable HLR under a constant COD. Within the range of COD concentrations considered (42 mg L(-)(1)-135 mg L(-)(1)) it was found that at fixed hydraulic loading rate, a decrease in the influent concentrations of dissolved organic carbon (DOC), biochemical oxygen demand (BOD), total nitrogen and phosphate improved their removal efficiencies. At the high COD concentrations applied residence times influenced the redox conditions in the soil column. Long residence times were detrimental to the removal process for COD, BOD and DOC as anoxic processes and sulphate reduction played an important role as electron acceptors. It was found that total COD mass loading within the range of 911 mg d(-)(1)-1780 mg d(-)(1) applied as low COD wastewater infiltrated coupled with short residence times would provide better effluent quality than the same mass applied as a COD with higher concentration at long residence times. The opposite was true for organic nitrogen where relatively high concentrations coupled with long residence time gave better removal efficiency.

No description available.

<p>An electro-optical sensor module was designed to monitor the level of dissolved oxygen (DO) using the method of frequency domain fluoroscopy. Frequency domain fluoroscopy is an optical method that detects the concentration of an analyte by indirectly monitoring the fluorescent lifetime decay. A planar film containing oxygen sensitive fluorophores interacts with a liquid solution, where the percent DO dictates the fluorescent lifetime decay. Amplitude modulated LED emission is created using an electrically implemented oscillator, exciting the oxygen sensitive fluorophores. The emission light from the fluorophores is detected by a photodiode and conditioned. The timing characteristics of the excitation and emission light waveforms are interpreted by a microcontroller. Time delay values have been correlated to actual percent DO values experimentally, and appropriate data modeling has been implemented for calibration purposes. This design is appropriate for application in bioreactors, presenting a functional and cost effective design. Future research can be performed to extrapolate the microcontroller platform to host a pH module, cell number module and glucose module, providing sufficient feedback to an automated bioreactor systems.</p> / Master of Applied Science (MASc)

O presente trabalho foi desenvolvido para avaliar o potencial de utilização de um reator anaeróbico fabricado em PEAD Polietileno de Alta Densidade, produzido pelo processo de rotomoldagem em substituição aos reatores convencionais construídos em concreto e alvenaria, trabalhando em regime de batelada e enterrados no solo. Os estados de tensões e deformações foram avaliados utilizando o programa de Elementos Finitos ABAQUS versão 6.5 e a malha dos nós utilizando o programa MSC PATRAN 2005 formando 7329 nós e 2004 elementos, em uma malha otimizada para as regiões de maior curvatura (pontos concentradores de tensão). O carregamento é formado com uma pressão interna do biogás de 5 kPa acrescido da carga hidrostática de biomassa de 6000 kgf em uma fundação elástica calculada pela razão tensão/recalque a partir do Módulo de Elasticidade equivalente do solo (Esolo). Comparando o estado de tensões avaliado durante o carregamento foi possível constatar que a maior tensão obtida no elemento mais crítico para a utilização mais provável do reator atingiu o valor de 7,46 MPa (não supera 40% do menor valor de resistência à tração e ao cisalhamento do PEAD de 20 MPa) e a maior razão de deformação dR/R foi de 1.0%. O caso mais crítico avaliado foi quando o reator está enterrado, totalmente vazio, em solo com Esolo = 1,55 MPa e o material com EPEAD = 1550 MPa e com uma sobrecarga superficial no terreno de 20kN/m2 gerando uma tensão de 17,80 MPa no elemento 1955 (atingindo 89% do menor valor de resistência à tração e ao cisalhamento do PEAD igual a 20 MPa). Os resultados obtidos comprovam que o reator produzido em PEAD substitui com vantagens os modelos fabricados em concreto ou alvenaria, suportando a pressão interna do biogás e a carga de biomassa. / The present work was developed to evaluate the potential of uses of an anaerobic reactor manufactured in HDPE High Density Polyethylene produced by the rotomolding process in substitution to the conventional reactors built in stonemasonry, working in a batch regime and buried in the soil. The state of tensions and the deformations were assessed using the program of Finite Elements ABAQUS version 6.5 and the mesh of the knots using the program MSC PATRAN 2005 forming 7329 knots and 2004 elements, in an optimized mesh for the areas of larger curvature (tension concentrator points). The loading is formed with an internal pressure of the biogas of 5kPa added of biomass hydrostatic load of 6000 kg in an elastic foundation calculated by the ratio pressure/settling starting from the Module of equivalent Elasticity of the soil (Esolo). Comparing the state of tensions assessed during the loading was possible to verify that the largest tension obtained in the most critical element goes the most probable utilization of the reactor, reached the value of 7, 46 MPa (it doesn't surpass 40% of the smallest resistance value to the traction and to the shearing strain of HDPE of 20 MPa) and the largest ratio of dR/R deformation was of 1.0%. The most critical assessed case was when the reactor is buried in soil with Esolo = 1,55 MPa and material with EPEAD = 1550 MPa, totally empty and with a superficial overload in the land of 20kN/m2 generating a tension of 17,80 MPa in the element 1955 (reaching 89% of the smallest resistance value to the traction and the shearing strain of a 20 MPa HDPE). The obtained results confirmed that the reactor produced in HDPE substitutes with advantages the models manufactured in stonemasonry, supporting the internal biogas pressure and the biomass load.

Thesis submitted in the requirements for the degree Doctor Technologiae: Chemical Engineering in the Faculty of Engineering at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY, 2013 / To date, limited information has been published on textile wastewater treatment, for re-use, in South Africa (SA), with treatment processes focusing on conventional wastewater treatment methods. A large contributor to the contamination of water within textile industries is from dyehouse processes. A major concern in textile wastewater treatment is the release of azo dyes and their metabolites, some of which are carcinogenic and mutanogenic, into the environment since they are xenobiotic and aerobically recalcitrant to biodegradation. A necessity therefore exists to find an effective treatment method capable of removing both the strong colour and the toxic organic compounds from textile wastewater. Membrane bioreactors (MBRs) are favoured when treating high-strength wastewater, since the membrane area is determined by the hydraulic throughput and not the biological load; no sludge is wasted and all bacteria are retained within the reactor, including specific bacteria capable of degrading the toxic, non-biodegradable constituents present in textile wastewater. MBR systems, using various configurations have been utilised extensively in the rest of the world to treat textile wastewater at both lab and pilot-scale. This DTech project formed part of a collaborative Water Research Commission (WRC) funded project K5/1900 - Pilot application of a dual-stage membrane bioreactor (dsMBR) for industrial wastewater treatment. The main purpose of this study was the on-site evaluation of a pilot-scale dsMBR incorporating two ultrafiltration (UF) sidestream membrane modules for the treatment, recovery and re-use of textile wastewater. The objectives of this project were to determine the treatment efficiency of the system; to evaluate the degree of colour removal from the textile wastewater; to improve residual colour removal within the system using treatment processes, such as NF and RO, as well as to propose a design and cost for a full-scale plant. A textile industry located in Bellville, Western Cape, was chosen as the industrial partner for the on-site evaluation of a semi-automated pilot wastewater treatment MBR plant using two 5.1 m2 Norit X-flow AirliftTM membrane modules. Since the wastewater treatment system was located on the premises, real continuously changing industrial wastewater was being treated. The industrial textile wastewater was treated in a series of tanks: 1) an anaerobic tank, which cleaved the azo bonds of the reactive dyes; 2) an anoxic tank containing reduced amounts of dissolved oxygen, in which denitrification occurred; and 3) an aerobic tank, in which i) nitrification, as well as ii) mineralisation of the aromatic amines occurred. The UF-membrane modules would account for the removal of any organic material. The wastewater stream was characterised by a chemical oxygen demand (COD) range of between 45 to 2,820 mg/L and an average biological oxygen demand (BOD) of 192.5 mg/L. The dsMBR achieved an average COD reduction of 75% with a maximum of 97% over the 220 day test period. The COD concentration obtained after dsMBR treatment averaged at 191 mg/L, which was well within the City of Cape Town industrial wastewater discharge standard. The average reduction in turbidity and TSS was 94% and 19.6%, respectively, during the UF-MBR stage of the system. Subsequent treatment of the UF permeate with nanofiltration (NF) for 4 days, alternated with reverse osmosis (RO) for 14 days removed both the residual colour and salt present in the UF permeate. A consistent reduction in the colour of the incoming wastewater was evident. The colour in the wastewater was reduced from an average of 659 ADMI units to ~12 ADMI units in the NF permeate, a lower American dye manufacturing index (ADMI) (i.e. method of colour representation) compared to the potable water (~17 ADMI units) utilised by the industrial partner in their dyeing processes. The colour was reduced from an average of 659 to ~20 ADMI units in the RO permeate, a lower ADMI and therefore colour when compared to the potable water. An average conductivity rejection of 91% was achieved with conductivity being reduced from an average of 7,700 to 693 μS/cm and the TDS reduced from an average of 5,700 to 473 mg/L, which facilitated an average TDS rejection of 92%. Based on the composition of the UF permeate fed to the RO membrane a maximum removal of 98.7% was achieved for both conductivity and total dissolved solids (TDS). The proposed full-scale plant would incorporate a UF-MBR system, followed by NF, RO, flocculation and a filter press. Therefore, the two waste products produced during operation of the proposed full-scale plant, would be the solid filter cakes and the liquid filtrate from the filter press. Implementing the proposed full-scale plant it would cost the industrial partner an operating cost of ZAR 113.85 and ZAR 3,415.49 to treat 97.1 m3 and 2,913 m3 of textile wastewater, respectively, per day and per month. This results in an annual saving of ZAR 845,848 on potable water expenses. This research, would provide SA textile industries, with an option to: 1) reduce their water consumption, thereby utilising less of a valuable decreasing commodity; 2) meet the SA government discharge standards and reduce their discharge costs; 3) reduce their carbon footprint (i.e. reduce their impact on the environment) by re-using their treated wastewater and therefore using less water from the municipality; and 4) decrease their annual expenditure on water, since the treated wastewater would be available for re-use.

O presente trabalho foi desenvolvido para avaliar o potencial de utilização de um reator anaeróbico fabricado em PEAD Polietileno de Alta Densidade, produzido pelo processo de rotomoldagem em substituição aos reatores convencionais construídos em concreto e alvenaria, trabalhando em regime de batelada e enterrados no solo. Os estados de tensões e deformações foram avaliados utilizando o programa de Elementos Finitos ABAQUS versão 6.5 e a malha dos nós utilizando o programa MSC PATRAN 2005 formando 7329 nós e 2004 elementos, em uma malha otimizada para as regiões de maior curvatura (pontos concentradores de tensão). O carregamento é formado com uma pressão interna do biogás de 5 kPa acrescido da carga hidrostática de biomassa de 6000 kgf em uma fundação elástica calculada pela razão tensão/recalque a partir do Módulo de Elasticidade equivalente do solo (Esolo). Comparando o estado de tensões avaliado durante o carregamento foi possível constatar que a maior tensão obtida no elemento mais crítico para a utilização mais provável do reator atingiu o valor de 7,46 MPa (não supera 40% do menor valor de resistência à tração e ao cisalhamento do PEAD de 20 MPa) e a maior razão de deformação dR/R foi de 1.0%. O caso mais crítico avaliado foi quando o reator está enterrado, totalmente vazio, em solo com Esolo = 1,55 MPa e o material com EPEAD = 1550 MPa e com uma sobrecarga superficial no terreno de 20kN/m2 gerando uma tensão de 17,80 MPa no elemento 1955 (atingindo 89% do menor valor de resistência à tração e ao cisalhamento do PEAD igual a 20 MPa). Os resultados obtidos comprovam que o reator produzido em PEAD substitui com vantagens os modelos fabricados em concreto ou alvenaria, suportando a pressão interna do biogás e a carga de biomassa. / The present work was developed to evaluate the potential of uses of an anaerobic reactor manufactured in HDPE High Density Polyethylene produced by the rotomolding process in substitution to the conventional reactors built in stonemasonry, working in a batch regime and buried in the soil. The state of tensions and the deformations were assessed using the program of Finite Elements ABAQUS version 6.5 and the mesh of the knots using the program MSC PATRAN 2005 forming 7329 knots and 2004 elements, in an optimized mesh for the areas of larger curvature (tension concentrator points). The loading is formed with an internal pressure of the biogas of 5kPa added of biomass hydrostatic load of 6000 kg in an elastic foundation calculated by the ratio pressure/settling starting from the Module of equivalent Elasticity of the soil (Esolo). Comparing the state of tensions assessed during the loading was possible to verify that the largest tension obtained in the most critical element goes the most probable utilization of the reactor, reached the value of 7, 46 MPa (it doesn't surpass 40% of the smallest resistance value to the traction and to the shearing strain of HDPE of 20 MPa) and the largest ratio of dR/R deformation was of 1.0%. The most critical assessed case was when the reactor is buried in soil with Esolo = 1,55 MPa and material with EPEAD = 1550 MPa, totally empty and with a superficial overload in the land of 20kN/m2 generating a tension of 17,80 MPa in the element 1955 (reaching 89% of the smallest resistance value to the traction and the shearing strain of a 20 MPa HDPE). The obtained results confirmed that the reactor produced in HDPE substitutes with advantages the models manufactured in stonemasonry, supporting the internal biogas pressure and the biomass load.

Les cheminées et sédiments hydrothermaux actifs du Bassin de Guaymas (Mexique) hébergent diverses communautés microbiennes présentant différents métabolismes, y compris ceux impliqués dans les cycles biogéochimiques du soufre et du fer. Il est établi, que, dans ces écosystèmes dynamiques, les micro-organismes qui dépendent pour leur croissance des substrats présents dans leur environnement pourraient à leur tour, affecter localement la composition du fluide hydrothermal et la minéralogie des cheminées, la composition des sédiments, en favorisant la dissolution et/ou la précipitation de certaines phases minérales. Pour étudier ces interactions procaryotes-biotopes, et établir des liens entre la structure, l’activité et les signatures isotopiques des communautés microbiennes et les caractéristiques physico-chimiques des systèmes hydrothermaux du Bassin de Guaymas, une approche pluridisciplinaire mettant en oeuvre des techniques de microbiologie, de géochimie et d’isotopie, lors des cultures d’enrichissements en bioréacteur et des études de colonisation de substrats basaltiques a été réalisée. Ces travaux ont permis : 1) de caractériser la diversité des micro-organismes de différents compartiments de l’écosystème hydrothermal (cheminée et sédiments) du Bassin de Guaymas par des approches culturales et moléculaires ; 2) de décrypter le fonctionnement des cycles biogéochimiques du soufre et du fer en mettant en évidence la présence simultanée, à haute température et en anaérobiose, de micro-organismes sulfo-réducteurs, sulfato-réducteurs, sulfo-oxydants mais également ferri-réducteurs et ferro-oxydants ; et 3) de mieux comprendre les interactions procaryotes-minéraux-fluide en soulignant le rôle des microorganismes dans la modification des conditions environnementales, la formation de minéraux ainsi que leur rôle direct ou indirect dans les fractionnements des isotopes du Fer et Soufre. Ces études ont donc permis de montrer l’importance des interactions croisées entre les différents composantes : communautés microbiennes, le fluide (fluide hydrothermal, eaux interstitielles des sédiments, eau de mer) et les structures minérales des écosystèmes hydrothermaux. / Active hydrothermal chimney and sediments of the Guaymas Basin (Mexico) host various microbial communities with different metabolisms, including those involved in biogeochemical cycles of sulfur and iron. It is established that, in these dynamic ecosystems, microbial activity depends on the availability of substrates in their environment and that prokaryotes could, in return locally affect the composition of the hydrothermal fluid and mineralogical composition of the chimney or sediment, by mediating the dissolution and / or precipitation of some mineral phases. In order to study these prokaryotes-biotope interactions, and establish links between the structure, the activity and the isotopic signatures of microbial communities with the physico-chemical characteristics of hydrothermal systems of Guaymas Basin, a multidisciplinary approach based on the implementation of microbiology, geochemistry and isotope technics was performed using enrichment cultures in bioreactors and the study of the colonization of basaltic substrates. This work led to: 1) characterize the diversity of microorganisms in different hydrothermal compartments (chimney and sediments) of the Guaymas Basin using both cultural and molecular approaches; 2) to decrypt the functioning of sulfur and iron biogeochemical cycles, by highlighting the occurrence, at high temperature and anaerobic condition, of sulfur-reducing, sulfate-reducing, sulfur-oxidizing and also iron-reducing and iron-oxidizing prokaryotes ; and 3) to better understand the prokaryote-mineral-fluid interactions by pointing out the role of microorganisms in environmental condition changes, mineral precipitation and their direct or indirect role in iron and sulfur isotope fractionation. Thus these studies have demonstrated the importance of the cross-interactions between the different hydrothermal components: microbial communities, fluids (hydrothermal fluid, sediment pore water, sea water) and mineral structures.