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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.
1

Fate Modeling of Xenobiotic Organic Compounds (XOCs) in Wastewater Treatment Plants

Ghalajkhani, Rosita 04 November 2013 (has links)
Xenobiotic Organic Compounds (XOCs) are present in wastewater and wastewater-impacted environmental systems. Pharmaceuticals and personal care products are a broad and varied category of chemicals that are included among these compounds. Although, these compounds have been detected at low levels in surface water, concerns that these compounds may have an impact on human health and aquatic life, have led to increased interest in how XOCs are removed during wastewater treatment. Recognizing specific mechanisms in recent literature and simulating those mechanisms responsible for the removal of XOCs is the main objective of this study. Conventional models, such as the popular activated sludge models (ASM1, ASM2, etc), do not sufficiently address the removal processes; therefore, a fate model is created to provide a means of predicting and simulating removal mechanisms along with experimental analyses. GPS-X is a multi-purpose modeling tool for the simulation of municipal and industrial wastewater treatment plants. This software package includes conventional models as built-in libraries, which can be used as bases on which new models can be created. In this thesis, the removal mechanisms of XOCs are recognized and investigated; a new library for GPS-X is also created to include XOCs. As a first step the uncalibrated fate model, which includes all mechanisms of interest with their process rates and state variables, is developed using in GPS-X software. A modified ASM1 (Mantis model) is used as a basis for developing the fate model. Since only a group of mechanisms is responsible for the removal of each compound the mechanisms are categorized in three different case studies as the next step. Thus, one submodel is associated with each case study. The model developer toolbar in GPS-X software is used to develop the model for these case studies. The first case study involves the removal of antibiotics, such as Sulfamethoxazole. The removal mechanisms used in this case are biodegradation, sorption, and parent compound formation, with co-metabolism and competitive inhibition effects being inserted into the structure of the model. Secondly, the removal of nonylphenol ethoxylates (NPEOs) occurs through abiotic oxidative cleavage, hydrolysis, and biodegradation. The third case study includes removal mechanisms of biodegradation and sorption for neutral and ionized compounds. In the calibration process, model parameters are tuned such that the model can best simulate the experimental data using optimization methods. A common error criterion is Sum of Squared Errors (SSE) between the simulated results and the measured data. By minimizing SSE, optimal values of parameters of interest can be estimated. In each case study different data sets were used for the validation process. To validate the calibrated model, simulated results are compared against experimental data in each case study. The experimental data set used in the validation process is different from that used for calibrating the model, which means the validation process data set was obtained from the different literature. By looking at the validation results, it is concluded that the proposed model successfully simulates removal of XOCs. Since the operating parameters of wastewater treatment plants, such as Solids Retention Time (SRT) and Hydraulic Retention Time (HRT) are crucial for the fate of XOC???s, a sensitivity analysis is carried out to investigate the effect of those parameters. Moreover, the pH effect is studied because it relates to the ionized XOCs. Sensitivity analysis results show that the fate model is more sensitive to model parameters i.e. biodegradation rate constant (kb) than the operational parameters, i.e. SRT and HRT. Furthermore, the responses showed sensitivity to pH, whereby acidic conditions provide a better environment for removing neutral forms and alkaline conditions were suitable for removing ionized forms, according to the ionized compound fate model.
2

Caracterização microbiana e degradação de surfactante aniônico em reator anaeróbio de leito fluidificado com água residuária de lavanderia / Microbial characterization and anionic surfactant degradation in an anaerobic fluidized bed reactor with laundry wastewater

Braga, Juliana Kawanishi 28 February 2014 (has links)
Neste estudo avaliou-se a remoção e degradação de surfactante aniônico linear alquilbenzeno sulfonado (LAS) e compostos orgânicos xenobióticos em água residuária de lavanderia comercial em reator anaeróbio de leito fluidificado (RALF) preenchido com areia como material suporte, em escala de bancada (1,2 L), bem como a comunidade microbiana do biofilme e biomassa do separador de fases ao final da operação. O reator foi inoculado com lodo proveniente de reator UASB utilizado no tratamento de dejetos de suinocultura e alimentado com substrato sintético acrescido de água residuária de lavanderia comercial. Caracterização da água residuária, análises de monitoramento da concentração de LAS e matéria orgânica, além de outros parâmetros físico-químicos foram realizadas durante as etapas de operação do sistema. Essa operação foi dividida em cinco etapas: I adaptação da biomassa (575±28mg.L-1 de DQO), II (9,5±3 mg.L-1 de LAS e 637±80mg.L-1 de DQO), III (23,3±8mg.L-1 de LAS e 686±92 mg.L-1 de DQO), IV (21,7±10mg.L-1 de LAS e 691±103 mg.L-1 de DQO), V (27,9±9,6mg.L-1 de LAS e 666±161mg.L-1 de DQO). Aplicação das técnicas de PCR/DGGE e pirosequenciamento da região do rRNA 16S foi realizada para constatar a diversidade microbiana nas etapas IV (com sacarose) e V (sem sacarose). Por meio da caracterização da água residuária de lavanderia comercial foi evidenciado grande variação na concentração de diversos parâmetros, principalmente matéria orgânica (704 mg.L-1 a 4.830 mg.L-1) e LAS (12,2 mg.L-1 a 11.949 mg.L-1). A eficiência média de remoção de matéria orgânica e LAS foi 88% e 60%, respectivamente, durante toda operação do reator. As populações dos Domínios Archaea e Bacteria foram 54% e 45%, similares, respectivamente, para a biomassa da Etapa IV e Etapa V. Por meio da análise de pirosequenciamento das amostras das Etapas IV e V da areia e separador de fases do reator foram identificados 92 gêneros dos quais 24 foram relacionados com a degradação de LAS (Bdellovibrio, Ferruginibacter, Gemmatimonas, etc.). / In this study the removal and degradation of anionic surfactant linear alkylbenzene sulfonate (LAS) and xenobiotic organic compounds in a commercial laundry wastewater was evaluated in anaerobic fluidized bed reactor (AFBR) filled with sand as support material, in a bench scale (1, 2 L), as well as the microbial community of the biofime and phase separator biomass at the end of the operation. The reactor was inoculated with sludge from a UASB reactor used in the swine manure treatment and fed with synthetic substrate plus commercial laundry wastewater. Wastewater characterisation, monitoring analyzes of LAS, organic matter and other physico-chemical parameters were performed during the stages of system operation. This operation was divided into five stages: Stage I - biomass adaptation (575 ± 28mg L-1 of COD), Stage II (9.5 ± 3 mg L-1 of LAS and 637 ± 80 mg L-1 of COD ), Stage III (23.3 ± 8 mg L-1 of LAS and 686 ± 92 mg L-1 of COD), Stage IV (21.7 ± 10 mg L-1 of LAS and 691 ± 103 mg L-1 of COD), Stage V (27.9 ± 9.6 mg L-1 of LAS and 666 ± 161 mg L-1 of COD). Application of PCR/DGGE and pyrosequencing of the 16S rRNA region was performed to verify the microbial diversity in the operational phase IV (with sucrose) and V (without sucrose). Through the commercial laundry wastewater characterization a wide variation in several parameters concentration was shown, mainly organic matter (704mg L-1 to 4.830mg L-1) and LAS (12.2mg L-1 to 11.949mg L-1). The average removal efficiency of organic matter and LAS was 88% and 60%, respectively, throughout the reactor operation. The populations of the Archaea and Bacteria Domains were 54% and 45% similar, respectively, for Stages IV and V biomass. By pyrosequencing analysis of sand and phase separator samples from the Stages IV and V, 92 genera of which 24 were related to the degradation of LAS (Bdellovibrio, Ferruginibacter, Gemmatimonas, Holophaga, Magnetospirillum, Zoogloea, etc.) were identified.
3

Caracterização microbiana e degradação de surfactante aniônico em reator anaeróbio de leito fluidificado com água residuária de lavanderia / Microbial characterization and anionic surfactant degradation in an anaerobic fluidized bed reactor with laundry wastewater

Juliana Kawanishi Braga 28 February 2014 (has links)
Neste estudo avaliou-se a remoção e degradação de surfactante aniônico linear alquilbenzeno sulfonado (LAS) e compostos orgânicos xenobióticos em água residuária de lavanderia comercial em reator anaeróbio de leito fluidificado (RALF) preenchido com areia como material suporte, em escala de bancada (1,2 L), bem como a comunidade microbiana do biofilme e biomassa do separador de fases ao final da operação. O reator foi inoculado com lodo proveniente de reator UASB utilizado no tratamento de dejetos de suinocultura e alimentado com substrato sintético acrescido de água residuária de lavanderia comercial. Caracterização da água residuária, análises de monitoramento da concentração de LAS e matéria orgânica, além de outros parâmetros físico-químicos foram realizadas durante as etapas de operação do sistema. Essa operação foi dividida em cinco etapas: I adaptação da biomassa (575±28mg.L-1 de DQO), II (9,5±3 mg.L-1 de LAS e 637±80mg.L-1 de DQO), III (23,3±8mg.L-1 de LAS e 686±92 mg.L-1 de DQO), IV (21,7±10mg.L-1 de LAS e 691±103 mg.L-1 de DQO), V (27,9±9,6mg.L-1 de LAS e 666±161mg.L-1 de DQO). Aplicação das técnicas de PCR/DGGE e pirosequenciamento da região do rRNA 16S foi realizada para constatar a diversidade microbiana nas etapas IV (com sacarose) e V (sem sacarose). Por meio da caracterização da água residuária de lavanderia comercial foi evidenciado grande variação na concentração de diversos parâmetros, principalmente matéria orgânica (704 mg.L-1 a 4.830 mg.L-1) e LAS (12,2 mg.L-1 a 11.949 mg.L-1). A eficiência média de remoção de matéria orgânica e LAS foi 88% e 60%, respectivamente, durante toda operação do reator. As populações dos Domínios Archaea e Bacteria foram 54% e 45%, similares, respectivamente, para a biomassa da Etapa IV e Etapa V. Por meio da análise de pirosequenciamento das amostras das Etapas IV e V da areia e separador de fases do reator foram identificados 92 gêneros dos quais 24 foram relacionados com a degradação de LAS (Bdellovibrio, Ferruginibacter, Gemmatimonas, etc.). / In this study the removal and degradation of anionic surfactant linear alkylbenzene sulfonate (LAS) and xenobiotic organic compounds in a commercial laundry wastewater was evaluated in anaerobic fluidized bed reactor (AFBR) filled with sand as support material, in a bench scale (1, 2 L), as well as the microbial community of the biofime and phase separator biomass at the end of the operation. The reactor was inoculated with sludge from a UASB reactor used in the swine manure treatment and fed with synthetic substrate plus commercial laundry wastewater. Wastewater characterisation, monitoring analyzes of LAS, organic matter and other physico-chemical parameters were performed during the stages of system operation. This operation was divided into five stages: Stage I - biomass adaptation (575 ± 28mg L-1 of COD), Stage II (9.5 ± 3 mg L-1 of LAS and 637 ± 80 mg L-1 of COD ), Stage III (23.3 ± 8 mg L-1 of LAS and 686 ± 92 mg L-1 of COD), Stage IV (21.7 ± 10 mg L-1 of LAS and 691 ± 103 mg L-1 of COD), Stage V (27.9 ± 9.6 mg L-1 of LAS and 666 ± 161 mg L-1 of COD). Application of PCR/DGGE and pyrosequencing of the 16S rRNA region was performed to verify the microbial diversity in the operational phase IV (with sucrose) and V (without sucrose). Through the commercial laundry wastewater characterization a wide variation in several parameters concentration was shown, mainly organic matter (704mg L-1 to 4.830mg L-1) and LAS (12.2mg L-1 to 11.949mg L-1). The average removal efficiency of organic matter and LAS was 88% and 60%, respectively, throughout the reactor operation. The populations of the Archaea and Bacteria Domains were 54% and 45% similar, respectively, for Stages IV and V biomass. By pyrosequencing analysis of sand and phase separator samples from the Stages IV and V, 92 genera of which 24 were related to the degradation of LAS (Bdellovibrio, Ferruginibacter, Gemmatimonas, Holophaga, Magnetospirillum, Zoogloea, etc.) were identified.

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