La présence de cations de métaux de transition en grandes concentrations dans les eaux présente des risques pour la santé humaine et pour l'environnement. Une des méthodes les plus utilisées pour les éliminer est la coagulation-floculation. Il s'agit d'une étape essentielle dans la chaîne de traitement des eaux. Cependant, l'utilisation de cette méthode pour traiter une eau de faible turbidité est difficile. Le recours à l'ajout de montmorillonite est d'un grand intérêt dans ce cas, car cela permet d'intensifier le processus de coagulation-floculation. Afin d'améliorer ce processus, l'ajout d'un floculant, non polluant, non toxique et biodégradable, s'avère nécessaire, d'où l'utilisation du chitosane qui joue deux rôles essentiels: il favorise à la fois la floculation et la complexation des cations des métaux de transition. Le présent travail a pour objet d'étudier l'élimination de trois cations de métaux de transition, à savoir le cobalt, le nickel et le cuivre, par coagulation-floculation du système montmorillonite-chitosane. L'élimination des cations métalliques et de la turbidité de l'eau dépend de plusieurs facteurs, dont le pH et le rapport massique (chitosane/montmorillonite). De même, les concentrations de cations, de chitosane et de montmorillonite peuvent, elles aussi, avoir un effet sur l'élimination de ces cations. Étant donné la multitude des facteurs pouvant influencer l'élimination de ces cations par la montmorillonite et par le chitosane, ainsi que la coagulation-floculation du système montmorillonite-chitosane, l'utilisation d'un plan factoriel s'est avérée nécessaire pour surmonter cette difficulté et déterminer les conditions favorables à une élimination optimale des trois cations étudiés. Les résultats obtenus prouvent qu'il peut exister une synergie entre le chitosane et la montmorillonite dans l'élimination des cations métalliques. La montmorillonite, dont l'efficacité a augmenté après modification chimique, et le chitosane ont montré une affinité différente pour chacun des trois cations métalliques. Cette affinité augmente dans l'ordre suivant: CO²⁺ < Ni²⁺ < Cu²⁺ . Une meilleure coagulation-floculation ne donne pas forcément une meilleure élimination des cations métalliques. Ainsi, l'élimination des cations dans une solution contenant 1 à 3 (g/L) de montmorillonite augmente avec l'augmentation du pH entre 3 et 7, tandis que la turbidité minimale est obtenue à un pH = 5,4 et pour un rapport massique (chitosane/montmorillonite) =0,6%. Ces conditions jugées optimales dans le cadre du présent travail peuvent faire l'objet d'une étude ultérieure plus poussée, visant la mise en oeuvre d'une technologie de démétallisation des eaux. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Chitosane, Montmorillonite, Coagulation, Floculation, Cations métalliques, Synergie.

Made available in DSpace on 2014-06-11T19:24:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-02-13Bitstream added on 2014-06-13T20:52:28Z : No. of bitstreams: 1 giovanni_g_me_botfca.pdf: 297824 bytes, checksum: b42e7912f9eb1618cd0ccc7c41f0c23c (MD5) / As águas residuárias dos processos de extração vegetal para fins farmacêuticos apresentam elevada DQO (Demanda Química de Oxigênio) e orgânicos persistentes que não são eliminados pelos tratamentos de resíduos líquidos convencionais. Atualmente, a fotocatálise heterogênea vêm se destacando como processo de oxidação avançado (POA) capaz de mineralizar compostos persistentes responsáveis pela poluição do meio ambiente aquático. Este trabalho tem o propósito de descontaminar o efluente semi-tratado de um indústria de extração vegetal, situada na região de Botucatu, São Paulo, Brasil; para seu posterior reuso, a fotocatálise (TiO2 em suspensão) foi aplicada. Foram realizados testes com variação do pH da amostra em que se obteve maior eficiência de fotodegradação em pH 4,0. Foi testado a adição de persulfato de potássio em várias concentrações, constatando que a adição 0,1 g L-1 favorece a degradação dos poluentes mais persistentes remanescentes do efluente semi-tratado. Finalmente, com o objetivo de remover o TiO2 da suspensão foram realizados testes de coagulação-floculação, na presença de sulfato de alumínio e pH 4,0. O tempo de decantação do material em suspensão foi de 30 minutos, DQO final de 2,5 mg O2 L-1 e a turbidez final de 2 NTU. A fotocatálise contribuiu para a remoção de tóxicos persistentes, redução da DQO, eliminação de odores e redução da turbidez do efluente. / The wastewater of vegetable extraction process (for pharmaceutical use) present increased DQO (Qhemistry Demand of Oxigen) and bio-recalcitrant organic contaminant that are not eliminated by convencional wastewater treatments. Presently, the heterogen photocatalysis is been outstanding as advanced oxidation process (AOP) capable of decaying of recalcitrant compounds, responsible for the pollution of the aquatic environment. This paper have to purpose of descontaminate the pretreated wastewater by vegetable extraction industry, located in Botucatu region, São Paulo, Brazil; the photocatalysis (TiO2 suspension) was applicated, for it is future reuse. Experiments were carried out with various pH samples with efficient results of photodegradation in pH 4,0. Experiments with the peroxydisulphat addition have done in various concentrations, concluding that it is minimum addition (0,1 g L-1) favours the degradation speed of the moust recalcitrants polluants of the pretreated wastewater. Eventually, experiments of coagulation-floculation have been done to remove the TiO2 (0,5 g L-1) from the suspension, in presence of aluminium sulphate (0,2 g L-1) and pH 4,0. The time of decantation of the suspension material was 30 minutes, the final turbidity 2 NTU and final DQO 2,5 mg O2 L-1. The photocatalysis contributed to remove recalcitrant organic compounds, to reduce the DQO, eliminated the smell and to redecue the wastewater turbidity.

Orientador: Ariovaldo de Oliveira Florentino / Banca: Cristiane Barbieri Rodella / Banca: José Pedro Serra Valente / Resumo: As águas residuárias dos processos de extração vegetal para fins farmacêuticos apresentam elevada DQO (Demanda Química de Oxigênio) e orgânicos persistentes que não são eliminados pelos tratamentos de resíduos líquidos convencionais. Atualmente, a fotocatálise heterogênea vêm se destacando como processo de oxidação avançado (POA) capaz de mineralizar compostos persistentes responsáveis pela poluição do meio ambiente aquático. Este trabalho tem o propósito de descontaminar o efluente semi-tratado de um indústria de extração vegetal, situada na região de Botucatu, São Paulo, Brasil; para seu posterior reuso, a fotocatálise (TiO2 em suspensão) foi aplicada. Foram realizados testes com variação do pH da amostra em que se obteve maior eficiência de fotodegradação em pH 4,0. Foi testado a adição de persulfato de potássio em várias concentrações, constatando que a adição 0,1 g L-1 favorece a degradação dos poluentes mais persistentes remanescentes do efluente semi-tratado. Finalmente, com o objetivo de remover o TiO2 da suspensão foram realizados testes de coagulação-floculação, na presença de sulfato de alumínio e pH 4,0. O tempo de decantação do material em suspensão foi de 30 minutos, DQO final de 2,5 mg O2 L-1 e a turbidez final de 2 NTU. A fotocatálise contribuiu para a remoção de tóxicos persistentes, redução da DQO, eliminação de odores e redução da turbidez do efluente. / Abstract: The wastewater of vegetable extraction process (for pharmaceutical use) present increased DQO (Qhemistry Demand of Oxigen) and bio-recalcitrant organic contaminant that are not eliminated by convencional wastewater treatments. Presently, the heterogen photocatalysis is been outstanding as advanced oxidation process (AOP) capable of decaying of recalcitrant compounds, responsible for the pollution of the aquatic environment. This paper have to purpose of descontaminate the pretreated wastewater by vegetable extraction industry, located in Botucatu region, São Paulo, Brazil; the photocatalysis (TiO2 suspension) was applicated, for it is future reuse. Experiments were carried out with various pH samples with efficient results of photodegradation in pH 4,0. Experiments with the peroxydisulphat addition have done in various concentrations, concluding that it is minimum addition (0,1 g L-1) favours the degradation speed of the moust recalcitrants polluants of the pretreated wastewater. Eventually, experiments of coagulation-floculation have been done to remove the TiO2 (0,5 g L-1) from the suspension, in presence of aluminium sulphate (0,2 g L-1) and pH 4,0. The time of decantation of the suspension material was 30 minutes, the final turbidity 2 NTU and final DQO 2,5 mg O2 L-1. The photocatalysis contributed to remove recalcitrant organic compounds, to reduce the DQO, eliminated the smell and to redecue the wastewater turbidity. / Mestre

Sabiendo la afectación a la salud asociadas a la ingestión de Arsénico de origen mineral a través del agua de consumo en el sur de Perú, el presente estudio que busca aportar al abatimiento de este metaloide de una manera sostenible y compatible con las condiciones de acceso a insumos y a recursos que existen actualmente en la zona. Entre las metodologías de abatimiento de Arsénico, se seleccionó la tecnología convencional y se estableció como objetivo encontrar la mejor combinación de coagulante-floculante tanto en tipología como en dosis para lo cual se estableció que el alcance de la presente tesis es aplicada, cuantitativa y experimental. El desarrollo de la presente investigación se basó en la realización de múltiplos ensayos vía Jar-Test mediante una metodología inductiva que se llevó a cabo mediante los siguientes pasos: A) caracterización del agua de la quebrada Uchusuma ubicada en el departamento de Tacna B) Jar- Tests’ de selección de coagulantes y floculantes. C) Establecimiento de dosis óptimas. D) ensayos confirmativos. De los floculantes probados se seleccionó el cloruro férrico por cuanto demostró el mejor desempeño en abatimiento de As con dosis óptimas entre 34 y 40ppm; así mismo seleccionó como mejor floculante un polímero catiónico con dosis óptima entre 0.30 y 0.40. Se realizó un análisis de estimación de costos, encontrando que para sistemas de potabilización de alto consumo el costo unitario oscilaría entre 0.022 y 0.026 $/m3, mientras que para pequeños proyectos mineros el costo unitario puede oscilar entre 0.055 y 0.068 $/m3. / Knowing the impact on health associated with the organic arsenic through drinking water in southern Peru, the present study seeks to contribute to removal this metalloid in a sustainable way and compatible with the conditions of access to supplies and resources that currently exist in the area. Among the arsenic abatement methodologies, the conventional technology was selected and the objective was to find the best combination of coagulant-flocculant both in type and in dosage for which it was established that the scope of this thesis is applied, quantitative and experimental. The development of the present investigation was based on the realization of multiple trials via Jar-Test through an inductive methodology that was carried out through the following steps: A) characterization of the water of the Uchusuma creek located in the department of Tacna B) Jar - Tests' of selection of coagulants and flocculants. C) Establishment of optimal doses. D) Confirmatory tests. Of the flocculants tested Ferric Chloride was selected because it showed the best performance in As removal, with optimal doses between 34 and 40 ppm; Likewise, we selected as the best flocculant a cationic polymer with an optimum dose between 0.30 and 0.40. A cost estimation analysis was carried out, finding that for high consumption potabilization systems the unit cost would oscillate between 0.022 and 0.026 $ / m3, while for small mining projects the unit cost can range between 0.055 and 0.068 $ / m3. / Trabajo de investigación

La régénération des solutions de lavage utilisées en Nettoyage En Place (NEP) présente un intérêt, tant économique qu’environnemental, pour les industriels laitiers. L’étape clé du NEP réside dans le lavage alcalin qui assure l’élimination des souillures organiques déposées sur les équipements. Ce lavage est généralement effectué par des lessives de soude, moins onéreuses que celles de potasse. Nos travaux ont visé à appliquer un procédé physico-chimique de régénération à des lessives de potasse en vue de rentabiliser leur intégration au NEP laitier. La régénération de solutions de potasse souillées par du lait a été examinée et comparée à celle de solutions de soude. L’efficacité du procédé à épurer les solutions de potasse en termes d’abattement de la DCO et de Ntot a été démontrée. L’analyse des solutions régénérées a par ailleurs mis en évidence l’amélioration de leurs propriétés interfaciales (tension superficielle, angle de contact). Ces propriétés, dont l’origine a pu être attribuée à l’accumulation de biotensioactifs, confèrent aux solutions de potasse régénérées un meilleur pouvoir nettoyant. Ce point a été validé lors d’essais de nettoyage de membranes organiques d’ultrafiltration colmatées par des protéines laitières. L’optimisation de la formulation de ces solutions a permis l’obtention de performances de nettoyage comparables à celles d’un détergent commercial classiquement utilisé pour ce type d’application. Enfin, les impacts économiques et environnementaux de l’intégration de lessives de potasse en substitution à celles de soude ont été évalués pour un NEP laitier industriel au travers d’une étude technico-économique et d’une Analyse de Cycle de Vie (ACV). / The regeneration of Cleaning In Place (CIP) solutions is interesting, both economically and environmentally, especially in dairy industry. The CIP’s key step lies on the alkaline washing which ensures the removal of organic contaminants deposited on the equipment. This washing is generally done by soda lyes, less expensive than potash ones. Our work aimed to apply a physicochemical regeneration process, based on adsorption-coagulation-flocculation phenomena, on potash lyes to make their integration in the dairy CIP affordable. The regeneration of potash solutions soiled with milk was examined and compared with the soda solutions regeneration. The process effectiveness to purify potash solutions in terms of COD and TN reduction has been shown. The solutions analysis has also highlighted the improvement of their interfacial properties (surface tension, contact angle). These properties, whose origin was attributed to the accumulation of biosurfactants, confer to potash regenerated solutions a best cleaning power. This point was validated during cleaning assays of organic ultrafiltration membranes fouled by milk proteins. The optimization of solutions formulation has also enabled obtaining a cleaning performance as efficient as those of a commercial detergent largely used for this type of application. Finally, economic and environmental impacts of the potash lyes integration in substitution to soda ones were evaluated for dairy industrial CIP through a techno-economic analysis and a Life Cycle Assessment (LCA).