• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 14
  • 10
  • 5
  • 3
  • 3
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 49
  • 13
  • 9
  • 9
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 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.
41

Desenvolvimento de metodologia analítica para controle de qualidade de polietoxinonilfenol éster fosfatado

Araujo, Daiane de January 2016 (has links)
Orientador: Prof. Dr. Alexandre Zatkovskis Carvalho / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Ciência e Tecnologia/Química, 2016. / Grupos alifáticos esterificados com fosfato apresentam diferentes propriedades físico-químicas, possibilitando diversas aplicações, dentre as quais a propriedade tensoativa. A Oxiteno Indústria e Comércio S.A., sintetiza ésteres de fosfato do polietoxinonilfenol, utilizados como dispersantes na aplicação de praguicidas. Um dos maiores desafios encontrados pela indústria é obter os referidos tensoativos com um grau de pureza adequado, pois os produtos finais são normalmente constituídos por uma mistura de isômeros, homólogos, resíduos de precursores e subprodutos de síntese, dificultando não apenas a análise, mas também comprometendo sua aplicação. Para que o mercado seja atendido de forma conveniente, é necessário estabelecer um método analítico de quantificação dos ésteres de fosfato derivados do polietoxinonilfenol. Neste trabalho são apresentados os resultados obtidos no desenvolvimento de metodologia para identificação e quantificação do polietoxinonilfenol éster fosfatado, assim como obtenção de padrões dos referidos tensoativos. Com estes objetivos, o presente estudo avaliou a aplicabilidade das técnicas de separação em alta eficiência cromatografia líquida e eletroforese capilar como proposta analítica, além de explorar a potencial purificação dos referidos tensoativos por cromatografia de troca iônica e por indução de ponto nuvem. Foi observado na cromatografia líquida que o pH da amostra afeta consideravelmente a separação, sendo que os melhores resultados foram obtidos com a amostra em pH 8,5, porém foi observada baixa reprodutibilidade dos resultados. A eletroforese capilar com detecção UV ou acoplada à espectrometria de massas apresentou melhores resultados, devido à eficiência e rapidez da técnica, além da reprodutibilidade dos resultados. Na purificação dos polietoxinonilfenóis ésteres fosfatados tanto a extração em ponto nuvem como a técnica de cromatografia de troca iônica se apresentaram promissores para a purificação dos tensoativos, apesar de não conseguir a purificação da amostra, foi possível eliminar alguns contaminantes da mesma. A técnica de cromatografia de troca iônica permitiu a eliminação de alguns interferentes dos tensoativos acima referidos. / Aliphatic groups esterified with phosphate have different physicochemical properties, enabling several applications, among them, the surfactant property. The Oxiteno Company LLC, synthesizes phosphate esters, utilized as dispersants on pesticides application. One of the main industrial challenges is to obtain the mentioned surfactant with the compliant purity of the final products which are usually composed from a blend of isomers, homologues , residual precursors and by-products, making a hard task not only on the analysis point of view, but also compromising its application. To attend the market properly, is necessary to stablish an analytical method to assess polyethoxy nonylphenol phosphate esters. In this work we present the results obtained on methodology development for the identification and quantification phosphated polyethoxy nonylphenol, as well as for obtaining standards of these surfactants. With these objectives, the present study have evaluated the applicability of the separation techniques high efficiency liquid chromatography and capillary electrophoresis as an analytical approach, besides evaluating purification by means of ion exchange chromatography and cloud point induction. It was observed in liquid chromatography that the sample pH affects significantly the separation, with best results obtained with the sample pH adusted to 8,5, however, it was observed low reproducibility of the results. Capillary electrophoresis with UV detection or coupled to mass spectrometry have presented better results, due to the efficiency and quickness of this technique, leading also to reproducibility enhancement. For phosphated polyethoxy nonylphenol purification cloud point extraction and ion exchange chromatography have showed promising results, although effective purification was not achieved, it was possible to eliminate some poisoning from the example. Ion exchange chromatography has allowed the elimination of some interfering on the surfactants mentioned above.
42

Fate and transport of herbicides in soil in the presence of surfactants in irrigation water

Nilufar, Fahmida. January 2005 (has links)
No description available.
43

Απομάκρυνση ξενοβιωτικών ουσιών κατά τη βιοσταθεροποίηση της ιλύος και άλλες αερόβιες διεργασίες

Πάκου, Κωνσταντίνα 07 April 2011 (has links)
Τις τελευταίες δεκαετίες η συνεχώς αυξανόμενη παγκόσμια δραστηριότητα, λόγω της έντονης αστικοποίησης και βιομηχανοποίησης, έχει σαν αποτέλεσμα την παραγωγή σημαντικών ποσοτήτων αποβλήτων. Μεταξύ αυτών είναι και η ιλύς, δηλαδή το ημιστερεό υπόλειμμα που παράγεται από τις μονάδες επεξεργασίας αστικών και βιομηχανικών αποβλήτων. Μολονότι η ιλύς αντιμετωπίζεται ως απόβλητο που πρέπει να διατεθεί, είναι στην πραγματικότητα ένας σοβαρά υποτιμημένος πόρος. Πιο συγκεκριμένα, η ιλύς διαθέτει πολύτιμα θρεπτικά συστατικά, ενώ παράλληλα έχει και υψηλή θερμική αξία, ιδιότητες που την καθιστούν κατάλληλη για ένα μεγάλο εύρος χρήσεων. Ωστόσο, η ιλύς είναι φορέας ρύπων, όπως οι παθογόνοι μικροοργανισμοί και οι ξενοβιοτικές ουσίες, η ύπαρξη των οποίων βρίσκεται στο επίκεντρο των ενδιαφερόντων των ερευνητών. Ανάμεσα στις διάφορες διεργασίες που έχουν εφαρμοσθεί μέχρι σήμερα τόσο για την επεξεργασία της ιλύος, όσο και για την απομάκρυνση των ξενοβιοτικών παραγόντων από το περιβάλλον, οι βιολογικές διεργασίες φαίνεται να υπερτερούν αισθητά έναντι των άλλων. Στόχος της παρούσας διατριβής ήταν η εφαρμογή μιας βιολογικής μεθόδου, της βιοσταθεροποίησης, για την επεξεργασία της ιλύος. Η ολοκλήρωση της μελέτης της βιοσταθεροποίησης έγινε με την ανάπτυξη ενός μαθηματικού μοντέλου ικανό να περιγράφει τη διεργασία. Παράλληλα, ερευνήθηκε η δυναμικότητα της διεργασίας αυτής στη βιοαποκατάσταση της ιλύος από το ξενοβιοτικό περιεχόμενό της. Επιπρόσθετα, μελετήθηκε η απομάκρυνση των ξενοβιοτικών ουσιών, μέσω της βιοαποδόμησής τους από αυτόχθονες μικροβιακούς πληθυσμούς της ιλύος, σε άλλα αερόβια περιβάλλοντα. Η εφαρμογή της διεργασίας της βιοσταθεροποίησης πραγματοποιήθηκε σε κατάλληλη πειραματική διάταξη που σχεδιάστηκε και υλοποιήθηκε για το σκοπό αυτό. Η διάταξη αυτή επέτρεπε τον πλήρη έλεγχο και τη σωστή ρύθμιση της διεργασίας. Η ολοκλήρωση των πειραμάτων της λιπασματοποίησης έδειξε ότι η διεργασία αυτή μπορεί να εφαρμοσθεί ως μέθοδος επεξεργασίας και σταθεροποίησης της ιλύος, αρκεί να ρυθμιστούν κατάλληλα καθοριστικές φυσικές και χημικές παράμετροι. Τα αποτελέσματα έδειξαν, επίσης, ότι η διεργασία δεν παρεμποδίζεται από την παρουσία υψηλών αρχικών συγκεντρώσεων ξενοβιοτικών ουσιών στην ιλύ, ενώ αντίθετα οδηγεί στην απομάκρυνσή τους. Τα ποσοστά απομάκρυνσης ήταν ιδιαίτερα υψηλά προκειμένου για τις επιφανειοδραστικές ενώσεις και αρκετά σημαντικά για το φθαλικό εστέρα και τους πολυκυκλικούς αρωματικούς υδρογονάνθρακες. Φαίνεται, λοιπόν, ο πολυποίκιλος μικροβιακός πληθυσμός της βιοσταθεροποίησης να συμβάλλει στην ουσιαστική, αν όχι πλήρη, απομάκρυνση των ξενοβιοτικών ουσιών κατά τη διάρκεια της διεργασίας και να οδηγεί στην παραγωγή σταθερού και ασφαλούς τελικού προϊόντος. Ωστόσο, υψηλά ποσοστά απομάκρυνσης των παραπάνω ξενοβιοτικών ουσιών κατέδειξαν και τα πειράματα που πραγματοποιήθηκαν σε αερόβιες υγρές μικτές καλλιέργειες. Ενδεχομένως, η μικροβιακή συνεργασία να παίζει τον καθοριστικό ρόλο στη βιοαποδόμηση αυτών των ουσιών. Η παρούσα μελέτη θα μπορούσε να συνεισφέρει αποτελεσματικά στην ανάπτυξη μιας αξιόπιστης μεθόδου για τη διαχείριση της ιλύος. Συνολικά, η λιπασματοποίηση μπορεί να αποδειχθεί ένα χρήσιμο εργαλείο για την επιθυμητή βιώσιμη ανάπτυξη της κοινωνίας μας, αφού αφ’ ενός μπορεί να συμβάλλει στη λύση του περιβαλλοντικού προβλήματος της διαχείρισης της ιλύος που παράγεται από τις εγκαταστάσεις επεξεργασίας λυμάτων, που την απασχολεί έντονα, και αφ’ ετέρου μπορεί να εξουδετερώσει το παθογόνο περιεχόμενο και να εξαλείψει τις τοξικές ξενοβιοτικές ουσίες. / The continuously increased human activity of the last few decades, because of the intense urbanization and industrialization, has resulted in the production of a serious amount of wastes. Among these is sewage sludge, which is the semi-solid residue produced by municipal and industrial waste treatment plants. Although sludge is considered as a waste product which must be disposed, it is actually an underestimated resource. Specifically, sludge contains valuable nutrients and high thermal value making sludge appropriate for a wide range of uses. Nevertheless, the existence of pathogens and xenobiotics in sludge has attracted the interest of scientific community. Among various methods that have been used for sludge treatment, as well as the removal of xenobiotics from environmental systems, biological methods are advantageous. The aim of the present work was to assess the sewage sludge treatment by a biological process, which is closed-vessel composting. This study involved also the development of a mathematical model capable of describing the composting process. The efficiency of bioremediation of xenobiotics content during sludge composting was also studied. Finally, the xenobiotics removal was investigated through biodegradation using sludge indigenous microbial populations in other aerobic environments. A suitable experimental configuration was designed and constructed in order to study the composting process. The composting system was designed for complete control and regulation of the process. Based on the results of the composting experiments, it can be concluded that composting is an efficient method allowing for treating and stabilization of sewage sludge, provided that critical physicochemical parameters are adjusted. Results revealed also that composting process is not inhibited by the presence of high initial concentration of xenobiotics. On the contrary, composting results in removal of xenobiotics. With reference to surfactants (LAS.NP and NPEO), the removal percentages were particularly high, while the relevant percentages for phthalate ester and polycyclic aromatics hydrocarbons were also significant. It seems, then, that the variable microbial population of the composting mixture contributes to the elimination of xenobiotic compounds and results in a safe and stable final product. The experiments which were conducted in aerobic mixed liquid cultures showed also high xenobiotic removal percentages. Probably, the microbial consortium could play a significant part in biodegradation of xenobiotic compounds. The present study contributes to the development of a reliable method of sewage sludge treatment. The composting process, totally complies with the desirable sustainable growth for our society by the treatment of sludge produced in waste water treatment plants and by the elimination of the xenobiotic compounds that limit its valorisation.
44

Optimalizace stanovení endokrinních disruptorů v čistírenských kalech a aplikace metody v reálných vzorcích. / Optimization of endocrine disruptors determination in wastewater treatment plant sludge and application of the method in environmental samples.

Medková, Jaroslava January 2012 (has links)
Hormonaly active compounds in wastewaters represent nowdays a serious problem. Proceses currently used in watewater treatment plants (WWTP) are unefficient in removing these compounds from contaminated wastewaters. The compounds are supposed to sorb onto solid sludge elements and sediments. In this work seven endocrine disruptors were detected in the sludge samples from WWTPs. A new sensitive method for detection of seven selected endocrine disruptors (4-nonylphenol, bisphenol A, estriol, 17β-estradiol, estrone, 17α- ethynylestradiol, irgasan) was developed. The method is based on accelerated solvent extraction (ASE), gel permeation chromatography (GPC) and solid phased extraction. For final extract analysis, gas chromatography coupled with mass spectrometry (GC/MS) was used. The efficiency of this method was tested using artificially contaminated sludge and the method was used to analyse real samples from several WWTPs in Czech Republic. The effect of sludge age on detection of individual analytes was assessed as well. The concentrations of endocrine disruptors measured in the samples reached up to 1 µg/g. The results are comparable or higher then those reported in other works and they show the necessity of further research on endocrine disruptors in the environment.
45

Tratabilidade de águas residuárias de indústrias petroquímicas - estudo de caso. / Treatability of petrochemical industries wastewaters - case study.

Hilsdorf, Antonio Sérgio de Carvalho 02 September 2008 (has links)
O tratamento de águas residuárias industriais, submetido constantemente a cargas de choque, é pouco estudado no Brasil, sendo limitado o grau de conhecimento que se tem no mundo sobre os mecanismos de remoção de disruptores endócrinos nos sistemas de tratamento físico-químicos e biológicos. O presente trabalho traz um estudo de caso, envolvendo uma indústria com uma composição de produtos muito diversificada, com despejos líquidos de unidades isoladas de qualidades diversas e que tem como uma das principais matérias-primas, nonil fenóis, conhecidos disruptores endócrinos. Os mecanismos de remoção de carga orgânica e a avaliação da toxicidade da água residuária ao processo biológico de tratamento foram estudados em escala de laboratório, enquanto que a sua tratabilidade por coagulação, floculação, flotação com ar dissolvido seguido de sistema de lodos ativados, em escala piloto. Avaliou-se, também, a aplicabilidade do tratamento biológico com carvão ativado em pó. A grande variação qualitativa e quantitativa da água residuária bruta requer uma unidade de equalização com tempo de detenção de pelo menos 30 horas. O maior responsável por esta variação de qualidade é o processo da unidade química, cujo efluente é proveniente de lavagens de tanques e reatores. Apesar da reduzida eficiência de remoção de DQO obtida com a coagulação, floculação e flotação com ar dissolvido (20 a 30%), constatou-se que este tratamento é essencial para a redução da toxicidade ao processo biológico. A dosagem de coagulante e o pH ótimos variam conforme a característica do despejo e devem ser determinadas diariamente. No sistema biológico, observou-se uma remoção significativa da DQO do efluente bruto gerado na indústria, não apenas por biodegradação, mas também por volatilização e adsorção. Os testes de bancada evidenciaram remoções de DQO por arraste com ar de 47 a 77 % e por adsorção no lodo biológico, de 42%. Apesar dos constantes choques de carga orgânica e de poluentes tóxicos, conseguiu-se atingir o estado estacionário com variações máximas da concentração de sólidos em suspensão voláteis no tanque de aeração entre 20 e 30%. Neste período, a idade do lodo situou-se em torno de 25 a 30 dias e o tempo de detenção hidráulico foi de 3,8 dias. A eficiência média de remoção de DQO neste período foi de 86%. Os testes com a unidade piloto demonstraram que a utilização de carvão ativado em pó (CAP) produz resultados satisfatórios, comprovando a redução de poluentes tóxicos da água residuária e refletindo em uma significativa melhora na biodegradabilidade do efluente, com aumento da concentração de sólidos em suspensão voláteis no tanque de aeração (de 1380 mg/L para 3820 mg/L) e redução da amplitude de variação da DQO do efluente tratado que passou de 600 a 3200 mgO2/L para o sistema sem CAP para 300 a 600 mgO2/L para o sistema com CAP. Notou-se, também, com a adição de CAP, melhoria na sedimentação do lodo. Pode-se concluir também que o sistema de tratamento atendeu a legislação atual do Estado de São Paulo, com uma remoção média de 80% da DBO5. / Wastewater treatment systems continuously receiving shock loads and the behavior of contaminants under unsteady state conditions are not very well documented in our country, with limited degree of knowledge in the world on the removal of specific pollutants like endocrine disrupting chemicals (EDC) in physical chemical and biological wastewater treatment systems. The present work brings a case study regarding an industry which wastewaters were generated from plants with multiproducts and campaign production with variable composition, and with nonylphenols as one of their raw materials which is known as an endocrine disrupting chemical. The organic load and toxicity removal mechanisms of the wastewater to the biological treatment were studied in bench scale whilst their treatability was evaluated through coagulation, flocculation, dissolved air flotation followed by activated sludge, in pilot scale. The feasibility of the addition of powdered activated carbon to the biological system was also studied. The large qualitative and quantitative variability of the wastewater requires an equalization time of at least 30 hours. The main responsible for this variability in quality is the chemical unit process which wastewaters are originated from reactors and tanks cleanings. Although the low efficiency in COD removal obtained with coagulation, flocculation and dissolved air flotation (20 to 30%), it was found that this process is essential to the toxicity reduction for the biological process. Optimum pH and coagulant dose vary with the wastewater characteristics, and must be determined on a daily basis. On the biological system, it was observed important raw wastewater COD elimination not only through biodegradation, but also through volatilization and adsorption. Bench tests revealed COD elimination of 47 to 77% by air stripping and 42% by adsorption onto the biological sludge. Despite of constant organic and toxic shock loads, it had been possible to reach the steady state during which the maximum variation on the volatile suspended solids concentration was 20 to 30%. During this period, sludge age was around 25 to 30 days, and the hydraulic detention time was 3,8 days. Average efficiency on COD removal in this period was 86%. Tests results with PAC dosage on the pilot plant showed satisfactory, proving the reduction of toxic compounds from the wastewater and resulting in biodegradability improvement. The increase of volatile suspended solids in the aeration tank was from 1380 mg/L to 3820 mg/L, and reduction in the range of variation of remaining treated water COD from 600 to 3200 mgO2/L (system without CAP) down to 300 to 600 mgO2/L (system with CAP). The improvement on the sludge sedimentation with PAC addition was also remarkable. One can also conclude the treatment system attained the current legislation of the State of São Paulo, with 80% BOD5 removal.
46

Toxicological Impact of Agricultural Surfactants on Australian Frogs

Mann, Reinier Matthew January 2000 (has links)
Surfactants are one of the more ubiquitous contaminants in aquatic systems. Their importance as toxic components of pesticide formulations has, however, been largely overlooked. Amphibians particularly, as inhabitants of shallow, temporary and often lentic aquatic environments may be at risk from exposure to these chemicals when they enter aquatic systems. This thesis presents data on the toxicity of surfactants to amphibians. Several experimental exposures were conducted with embryo-larval, tadpole and adult developmental stages of the Australian species- Crinia insignifera, Helcioporus eyrei, Limnodynastes dorsalis and Litoria moorei and the exotic species- Bufo marinus and Xenopus laevis. Animals were variously exposed to glyphosate formulations that contain a high proportion of nonionic surfactants, or commercial pesticide wetting agents (alcohol alkoxylate and nonylphenol ethoxylate (NPE) surfactants). Feeding stage tadpoles of C.insignifera, H. eyrei, L. dorsalis and L. moorei were exposed to three commercial glyphosate formulations, glyphosate isopropylamine and glyphosate acid in static-renewal acute toxicity tests. The 48-h LC50 values for Roundup Herbicide (MON 2139) tested against tadpoles of C. insignifera, H. eyrei, L. dorsalis and L. moorei ranged between 8.1 and 32.2 mg/L (2.9 and 11.6 mg/L glyphosate acid equivalent (ae)), while the 48-h LC50 values for Roundup Herbicide tested against adult and newly metamorphosed C. insignifera ranged from 137-144 mg/L (49.4-51.8 mg/L ae). / Touchdown Herbicide (4 LC-E) tested against tadpoles of C. insignifera, H. eyrei, L. dorsalis and L. moorei was slightly less toxic than Roundup with 48-h LC50 values ranging between 27.3 and 48.7 mg/L (9.0 and 16.1 mg/L ae). Roundup Biactive (MON 77920) was practically non-toxic to tadpoles of the same four species producing 48-h LC50 values of 911 mg/L (328 mg/L ae) for L. moorei and >1000 mg/L (>360 mg/L ae) for C. insignifera, H. eyrei and L. dorsalis. Glyphosate isopropylamine was practically non-toxic producing no mortality amongst tadpoles of any of the four species over 48 h, at concentrations between 503 and 684 mg/L (343 and 466 mg/L ae). The toxicity of technical grade glyphosate acid (48-h LC50, 81.2-121 mg/L) is likely to be due to acid intolerance. Feeding stage tadpoles of B. marinus, X laevis, C. insignifera, H.eyrei, L. dorsalis and L. moorei were exposed to NPE and alcohol alkoxylate in static renewal acute toxicity tests. All species exhibited non-specific narcosis following exposure to both these surfactants. The 48-h EC50 values for NPE ranged between 1.1 mg/L (mild narcosis) and 12.1 mg/L (full narcosis). The 48-h EC50 values for alcohol alkoxylate ranged between 5.3 mg/L (mild narcosis) and 25.4 mg/L (full narcosis). Xenopus laevis was the most sensitive species tested. The sensitivity of the other five species was size dependent with larger species displaying greater tolerance. Replicate acute toxicity tests with B. marinus exposed to NPE at 30 degrees celsius over 96 hours indicated that the narcotic effects were not particularly time dependant. / The mean 24, 48, 72 and 96-h EC50 (mild narcosis) were 3.6, 3.7, 3.5 and 3.5 mg/L respectively. The mean 24, 48, 72, and 96-h EC50 (full narcosis) values were 4.0, 4.1, 4.2 and 4.0 respectively. Acute toxicity tests with B. marinus exposed to NPE at 30 degrees celsius under conditions of low dissolved oxygen (0.8-2.3 mg/L) produced a two to threefold increase in toxicity. The 12-h EC50 values ranged from 1.4 to 2.2 mg/L. The embryotoxicity of NPE was determined in X. laevis, L. adelaidensis and C. insignifera using a Frog Embryo Teratogenesis assay-Xenopus (FETAX). The 96-h LC50, EC50 and MCIG (LOEC) values for X. laevis were 3.9 to 5.4 mg/L, 2.8 to 4.6 mg/L and 1.0 to 3.0 mg/L respectively. The 140-h LC50, ECSO and MCIG values for L. adelaidensis were 9.2 mg/L, 8.8 mg/L and 5.1 to 6.0 ing/L respectively. The 134-h LC50, EC50 and MCIG values for C. insignifera were 6.4 mg/L, 4.5 mg/L and 4.0 mg/L respectively. Teratogenicity indices for the three species ranged between 1.0 and 1.6 indicating either no or low teratogenicity. Xenopus laevis was the more sensitive of the three species and the only species that displayed indisputable terata. The acute toxicity data indicated that the amphibian species tested were of similar sensitivity to fish and some invertebrates. Developmental retardation and oestrogenic effects following exposure to nonylphenol ethoxylate were indicated by sublethal toxicity tests. Crinia insignifera embryos were exposed during early embryogenesis to sublethal concentrations of NPE. / Exposure to NPE did not affect either weight nor size (snout-vent length) at metamorphosis. Exposure to 5.0mg/L NPE resulted in a significant delay in the time required to reach metamorphosis. Also, exposure to 3.0 mg/L NPE for the first 6 days of embryonic development or exposure to 5.0 mg/L NPE from day 2 to day 6 resulted in a statistically significant predominance in the female phenotype amongst metamorphosing froglets. Exposure for the first five days to 1.5 ing/L or 3.0 mg/L NPE had no effect on sex ratio. The results indicated that exposure to NPEs has endocrine disruptive effects in this species and that a narrow window of susceptibility exists for the induction of predominantly female phenotype. This study has also followed the degradation of a mixture of NPE oligomers and the concomitant formation of individual oligomers in static die-away tests with and without illumination in freshwater. Over 33 days in darkness there was a progressive and complete loss of long chain oligomers (NPEO(subscript)8-17), transient increases and subsequent loss of short to medium chain oligomers (NPE0(subscript)4-7), and large persistent increases (approximately 1000%) in short chain oligomers (NPE0(subscript)1-3). In the presence of illumination, biodegradation was retarded and heterotrophic bacterial proliferation was inhibited. After 33 days there was complete loss of long chain oligomers (NPE0(subscript)9-17), incomplete loss of medium chain oligomers (NPE0(subscript)6.8) and increases in short chain oligomers (NPE0(subscript)1-5). / This thesis discusses the importance of persistent metabolites of NPE degradation as it pertains to the habitat, developmental time frame and ecology of amphibians. Degradation of NPE is likely to occur over a time frame that is longer than that required for complete embryogenesis and metamorphosis of many species of amphibians, and may easily encompass those critical stages of development during which oestrogenic metabolites can affect development.
47

Anàlisi simultània d’aflatoxines i ocratoxina A en compost i avaluació de la degradació del nonilfenol en sòls

Navajas Cortina, Helena 28 March 2012 (has links)
Aquest estudi s’ha realitzat en el marc del projecte titulat: “Ecotoxicidad, micotoxinas y degradación de nonilfenoles en lodos de depuradora y suelos tratados” finançat pel Ministeri d’educació i ciència amb número de referència: CTM2006-14163-C02-02, en col•laboració amb el Centre de Recerca i Aplicacions Forestals. La present Tesi Doctoral aborda els aspectes de determinació analítica de la presència de micotoxines en compost i l’evolució del nonilfenol en sòls. En concret, s’ha estudiat la presència de les aflatoxines G2, G1, B2, B1 i l’ocratoxina A, en tres mostres de compost produït en dues EDAR de Catalunya. Per això s’ha desenvolupat un mètode per a l’anàlisi simultània de les aflatoxines G2, G1, B2, B1 i l’ocratoxina A en compost. En primer lloc s’ha adaptat per aquestes mostres un procediment per HPLC-MS desenvolupat anteriorment en el nostre equip per a la determinació de les aflatoxines G2, G1, B2 i B1 aplicat en matrius de tipus alimentari, que s’ha estès a la determinació conjunta de les quatre aflatoxines i l’ocratoxina A. Aquest procediment ha mostrat problemes pel que fa a la recuperació i precisió dels resultats. Vistes les dificultats, s’ha desenvolupat un nou procediment per UHPLC-Fluorescència que permet una preparació de mostra més ràpida i simple, així com una millor sensibilitat. Aquest nou mètode ha estat validat i permet millorar el temps d’anàlisi i aconseguint eliminar l’etapa de purificació de mostra amb cartutxos de reblert polimèric, utilitzats en el mètode emprat com a punt de partida. Els dos procediment han permès demostrar que, en les mostres de compost estudiades no hi ha quantitats significatives de cap de les cinc micotoxines estudiades. Pel que fa al nonilfenol, s’ha estudiat la seva evolució temporal, durant 32 setmanes, en mostres de sòl, mescles de sòl amb torba i mescles de sòl amb compost, a les que s’ha addicionat nonilfenol a dos nivells de concentració. De la mateixa manera, s’ha estudiat la concentració de nonilfenol en els lixiviats de les mostres de sòl i de les mescles de sòl amb torba. Per això, s’ha posat al punt un procediment analític per HRGC-MS tant per a les mostres de sòls com per a les mostres aquoses dels lixiviats. S’ha posat de manifest la ràpida eliminació del nonilfenol en les tres mostres estudiades i que el nivell de pèrdua per lixiviació és molt baix. En els mateixos lixiviats s’ha determinat la matèria orgànica total i la seva toxicitat a través de l’assaig de Microtox. Les dues determinacions mostren que aquests lixiviats no presenten problemes ja que, complirien les exigències per poder ser abocats a les xarxes públiques de clavegueram. Finalment, es pot afirmar que l’ús del compost en agricultura és una pràctica segura, tant pel que fa a l’absència de les micotoxines, com per la ràpida degradació del nonilfenol en el sòl. / Este estudio se llevó a cabo en el marco del proyecto titulado, "Ecotoxicidad, micotoxinas y degradación de nonilfenoles en lodos de depuradora y suelos tratados" financiado por el Ministerio de educación y ciencia con número de referencia: CTM2006-14163-C02-01, en colaboración con el “Centre de Recerca i Aplicacions Forestals”. La presente Tesis Doctoral aborda los aspectos de determinación analítica de la presencia de micotoxinas en compost y la evolución del nonilfenol en suelos. En concreto, se ha estudiado la presencia de las aflatoxinas B1, B2, G1, G2 y la ocratoxina A en tres muestras de compost producido en dos EDAR de Catalunya. Por lo tanto, se ha desarrollado un método de análisis simultáneos de aflatoxinas B1, B2, G1, G2 y la ocratoxina A en compost. En primer lugar se ha adaptado a estas muestras un procedimiento por HPLC-MS desarrollado previamente en nuestro equipo para la determinación de aflatoxinas B1, B2, G1 y G2 aplicado a matrices alimentarias y se ha extendido a la determinación conjunta de las cuatro aflatoxinas y la ocratoxina A. Este procedimiento ha revelado problemas relativos a la recuperación y la precisión de los resultados. Vistas las dificultades, se ha desarrollado un nuevo procedimiento por UHPLC-fluorescencia que permite una rápida y simple preparación de muestra, así como una mejor sensibilidad. Este nuevo método ha sido validado y puede mejorar el tiempo de análisis y eliminar la etapa con cartuchos de purificación de muestra con cartuchos poliméricos, utilizados en el método de partida. Ambos procedimientos han permitido mostrar que, en las muestras del compost estudiado no hay cantidades significativas de ninguna de las cinco micotoxinas estudiadas. En cuanto a nonilfenol, se ha estudiado su evolución temporal, durante 32 semanas, en muestras de suelo, mezclas de suelo con turba y mezclas de suelo con compost, donde se ha adicionado nonilfenol en dos niveles de concentración. Asimismo, se ha estudiado la concentración del nonilfenol en las muestras de lixiviados de los suelos y mezclas de suelo con turba. Por lo tanto, se ha puesto a punto un procedimiento analítico por HRGC-MS tanto para muestras de suelo como para muestras de lixiviados acuosa. Se ha demostrado la rápida eliminación del nonilfenol en las tres muestras estudiadas y que el nivel de pérdidas por lixiviación es muy baja. Finalmente, en los mismos lixiviados se ha determinado la materia orgánica total y su toxicidad mediante el ensayo de Microtox. Ambas determinaciones muestran que estos lixiviados no presentan problemas ya que cumplen las exigencias para poder ser enviados a las redes de alcantarillado público. Se puede afirmar que el uso de compost en la agricultura es una práctica segura, tanto en cuanto a la ausencia de micotoxinas, como la degradación rápida de nonilfenol en el suelo. / This work was carried out in the framework of the project: “Ecotoxicidad, micotoxinas y degradación de nonilfenoles en lodos de depuradora y suelos tratados". This project was performed in collaboration with "Centre de Recerca i Aplicacions Forestals" and it was supported by “Ministerio de Educación y Ciencia” (contract number CTM2006-14163-C02-01). The present work is referred to the analytical determination of mycotoxins and the degradation of the nonylphenol in soils. Aflatoxins B1, B2, G1, G2 and ochratoxin A in three different samples of compost, produced in two sewage wastewater in Catalonia, has been studied. Also, a method for simultaneous determination of aflatoxins B1, B2, G1, G2 and ochratoxin A in compost has been developed. An analytical method using HPLC-MS has been developed to determinate aflatoxins B1, B2, G1, G2 and ochratoxin A in compost matrices. This method is based on a previous work performed in the Chromatographic Methods Lab at IQS to determinate aflatoxins B1, B2, G1, and G2 in food matrices. It is important to mention that the HPLC-MS method showed low recovery factors and precision problems in the compost samples analyzed. In a second set of experiments a new method using UHPLC-fluorescence has been designed to analyze aflatoxins B1, B2, G1, G2 and ochratoxin A in compost samples. UHPLC-fluorescence allowed quick and simple sample preparation, high sensitivity, short analysis time and the elimination of the purification step using polymeric cartridges. Finally, this method using UHPLC-fluorescence was validated for aflatoxins B1, B2, G1, G2 and ochratoxin A in compost matrices. It is important to mention that HPLC-MS and UHPLC-fluorescence methods verify the absence of mycotoxins in all compost samples analyzed. In a third set of experiments the temporal evolution of nonylphenol has been studied in soil samples, mixtures of soil with peat and soil with compost. The experiments were performed during 32 weeks in which nonylphenol was added at two levels of concentration in the samples at the beginning of the assay. Also, the concentration of nonylphenol in samples of leachates from soil and mixtures of soils with peat has been studied. An analytical method to analyze nonylphenol using HRGC-MS for soil samples and leachates has been designed. Rapid nonylphenol degradation in the three samples analyzed (soil, soil + compost and soil + peat) has been observed and very low nonylphenol levels in samples of leachates from soil and mixtures of soils have been obtained. Finally, Total Organic Carbon (TOC) of the leachates has been measured and also toxicity assays by Microtox test have been performed. Both techniques showed that the leachates analyzed can be dumped in the public sewerage networks because it’s low TOC and toxicity levels. To summarize, it can be assured that the use of compost in agriculture is a safe practice because the absence of mycotoxins and the rapid degradation of nonylphenol in soil.
48

Tratabilidade de águas residuárias de indústrias petroquímicas - estudo de caso. / Treatability of petrochemical industries wastewaters - case study.

Antonio Sérgio de Carvalho Hilsdorf 02 September 2008 (has links)
O tratamento de águas residuárias industriais, submetido constantemente a cargas de choque, é pouco estudado no Brasil, sendo limitado o grau de conhecimento que se tem no mundo sobre os mecanismos de remoção de disruptores endócrinos nos sistemas de tratamento físico-químicos e biológicos. O presente trabalho traz um estudo de caso, envolvendo uma indústria com uma composição de produtos muito diversificada, com despejos líquidos de unidades isoladas de qualidades diversas e que tem como uma das principais matérias-primas, nonil fenóis, conhecidos disruptores endócrinos. Os mecanismos de remoção de carga orgânica e a avaliação da toxicidade da água residuária ao processo biológico de tratamento foram estudados em escala de laboratório, enquanto que a sua tratabilidade por coagulação, floculação, flotação com ar dissolvido seguido de sistema de lodos ativados, em escala piloto. Avaliou-se, também, a aplicabilidade do tratamento biológico com carvão ativado em pó. A grande variação qualitativa e quantitativa da água residuária bruta requer uma unidade de equalização com tempo de detenção de pelo menos 30 horas. O maior responsável por esta variação de qualidade é o processo da unidade química, cujo efluente é proveniente de lavagens de tanques e reatores. Apesar da reduzida eficiência de remoção de DQO obtida com a coagulação, floculação e flotação com ar dissolvido (20 a 30%), constatou-se que este tratamento é essencial para a redução da toxicidade ao processo biológico. A dosagem de coagulante e o pH ótimos variam conforme a característica do despejo e devem ser determinadas diariamente. No sistema biológico, observou-se uma remoção significativa da DQO do efluente bruto gerado na indústria, não apenas por biodegradação, mas também por volatilização e adsorção. Os testes de bancada evidenciaram remoções de DQO por arraste com ar de 47 a 77 % e por adsorção no lodo biológico, de 42%. Apesar dos constantes choques de carga orgânica e de poluentes tóxicos, conseguiu-se atingir o estado estacionário com variações máximas da concentração de sólidos em suspensão voláteis no tanque de aeração entre 20 e 30%. Neste período, a idade do lodo situou-se em torno de 25 a 30 dias e o tempo de detenção hidráulico foi de 3,8 dias. A eficiência média de remoção de DQO neste período foi de 86%. Os testes com a unidade piloto demonstraram que a utilização de carvão ativado em pó (CAP) produz resultados satisfatórios, comprovando a redução de poluentes tóxicos da água residuária e refletindo em uma significativa melhora na biodegradabilidade do efluente, com aumento da concentração de sólidos em suspensão voláteis no tanque de aeração (de 1380 mg/L para 3820 mg/L) e redução da amplitude de variação da DQO do efluente tratado que passou de 600 a 3200 mgO2/L para o sistema sem CAP para 300 a 600 mgO2/L para o sistema com CAP. Notou-se, também, com a adição de CAP, melhoria na sedimentação do lodo. Pode-se concluir também que o sistema de tratamento atendeu a legislação atual do Estado de São Paulo, com uma remoção média de 80% da DBO5. / Wastewater treatment systems continuously receiving shock loads and the behavior of contaminants under unsteady state conditions are not very well documented in our country, with limited degree of knowledge in the world on the removal of specific pollutants like endocrine disrupting chemicals (EDC) in physical chemical and biological wastewater treatment systems. The present work brings a case study regarding an industry which wastewaters were generated from plants with multiproducts and campaign production with variable composition, and with nonylphenols as one of their raw materials which is known as an endocrine disrupting chemical. The organic load and toxicity removal mechanisms of the wastewater to the biological treatment were studied in bench scale whilst their treatability was evaluated through coagulation, flocculation, dissolved air flotation followed by activated sludge, in pilot scale. The feasibility of the addition of powdered activated carbon to the biological system was also studied. The large qualitative and quantitative variability of the wastewater requires an equalization time of at least 30 hours. The main responsible for this variability in quality is the chemical unit process which wastewaters are originated from reactors and tanks cleanings. Although the low efficiency in COD removal obtained with coagulation, flocculation and dissolved air flotation (20 to 30%), it was found that this process is essential to the toxicity reduction for the biological process. Optimum pH and coagulant dose vary with the wastewater characteristics, and must be determined on a daily basis. On the biological system, it was observed important raw wastewater COD elimination not only through biodegradation, but also through volatilization and adsorption. Bench tests revealed COD elimination of 47 to 77% by air stripping and 42% by adsorption onto the biological sludge. Despite of constant organic and toxic shock loads, it had been possible to reach the steady state during which the maximum variation on the volatile suspended solids concentration was 20 to 30%. During this period, sludge age was around 25 to 30 days, and the hydraulic detention time was 3,8 days. Average efficiency on COD removal in this period was 86%. Tests results with PAC dosage on the pilot plant showed satisfactory, proving the reduction of toxic compounds from the wastewater and resulting in biodegradability improvement. The increase of volatile suspended solids in the aeration tank was from 1380 mg/L to 3820 mg/L, and reduction in the range of variation of remaining treated water COD from 600 to 3200 mgO2/L (system without CAP) down to 300 to 600 mgO2/L (system with CAP). The improvement on the sludge sedimentation with PAC addition was also remarkable. One can also conclude the treatment system attained the current legislation of the State of São Paulo, with 80% BOD5 removal.
49

Aplikace ligninolytických hub na pevných substrátech pro degradace endokrinních disruptorů / Application of ligninolytic fungi on solid substrates for degradation of endocrine disrupters

Slavíková - Amemori, Anna January 2012 (has links)
Today a lot of attention is focused on compounds called endocrine disrupters (EDs) among substances released to environment by humans. They are a group of substances which can disturb function of hormonal system of organisms including humans. Their poor removal at wastewater treatment plants (WwTP) were shown at various studies, thus they can reach the environment in water. A prospective way for the degradation of EDs at WwTP can be their removal by ligninolytic fungi. They are able to degrade lots of lignin-like aromatic substances because of their highly nonspecific enzymes. In this work growth and enzyme production capability of four ligninolytic fungal strains were monitored on three solid substrates (straw pellets, poplar sawdust mixed with straw pellets, oak sawdust with straw pellets), which may be suitable substrates for fungal growth in bioreactors for wastewater treatment. Ability of these enzymes to degrade EDs were tested in in-vitro degradation experiment. Trametes versicolor was found as best degrading strain with 20 μg/ml of bisphenol A, 17 α- ethynylestradiol and nonylphenol degraded below a quantification limit within 24 hours. Fungal strains degraded EDs well on all of the three substrates but wood sawdust seemed to be a better substrate for fungal growth because straw pellets...

Page generated in 0.6621 seconds