Academic literature on the topic 'Recalcitrant compounds'

The main factors responsible for anaerobic recalcitrance are reviewed. Anaerobic recalcitrance is associated with hydrocarbons lacking functional groups, branched molecules (gasoline oxygenates), aromatic amines and aromatic sulfonates. The most recalcitrant compounds are high molecular weight non-hydrolyzable polymers such as plastic, lignin and humus, which cannot be taken up by cells. Recently new capabilities of anaerobic microorganisms have been discovered to degrade compounds previously considered to be recalcitrant. For example, anaerobic bacteria initiate the degradation of alkylbenzenes and alkanes with an unusual addition reaction with fumarate, forming a hydrocarbon-succinate adduct. Finally, new evidence indicates that the most recalcitrant compounds (humic substances) are not so inert and can play important roles in aiding the biodegradation of other compounds by serving as an electron acceptor or redox mediator.

Effluents originated in cellulose pulp manufacturing processes are usually toxic and recalcitrant, specially the bleaching effluents, which exhibit high contents of aromatic compounds (e.g. residual lignin derivates). Although biological processes are normally used, their efficiency for the removal of toxic lignin derivates is low. The toxicity and recalcitrance of a bleached Kraft pulp mill were assessed through bioassays and ultraviolet absorption measurements, i.e. acid soluble lignin (ASL), UV280, and specific ultraviolet absorption (SUVA), before and after treatment by an integrated system comprised of an anaerobic packed-bed bioreactor and oxidation step with ozone. Furthermore, adsorbable organic halides (AOX) were measured. The results demonstrated not only that the toxic recalcitrant compounds can be removed successfully using integrated system, but also the ultraviolet absorption measurements can be an interesting control-parameter in a wastewater treatment.

Anaerobic biological technology and bioelectrochemical technology are regarded as promising sustainable wastes treatment processes. With biocatalysis in BESs anode or cathode, various pollutants can be removed. The pollutants range from nitrogen and sulfur to complex compounds. However, the investigation on recalcitrant wastes removal with biocathode has only been reported recently. Recalcitrant wastes, especially chlorinated nitroaromatic compounds, are highly persistent and toxic environmental pollutions which should be removed before discharging to environment. This paper provides a review on anaerobic biocathode BESs for recalcitrant wastes treatment and the feasibility of this system for CANs transformation. It is expected that anaerobic biocathode BESs can provide an appropriate condition for these compounds to transform to easily degradable forms. The technical challenges for future research are also discussed.

This study investigates the use of UV absorption and fluorescence spectroscopy to assess the early development of recalcitrant organic compounds in leachates formed during the anaerobic biodegradation of municipal solid waste. Biochemical methane potential tests were carried out on fresh waste (FW) and composted waste (CW) over a period of 150 days and leachates produced from the degradation of two wastes were analysed for humic-like (H-L) and fulvic-like (F-L) structures by UV spectroscopy and fluorescence excitation–emission-matrix analyses. During anaerobic biodegradation, the synthesis and utilization of H-L and F-L structures in the leachates over time was indicative of the generation of the recalcitrant organic compounds. The results obtained from UV absorption and fluorescence spectroscopy suggested that CW leachates resulted in a higher concentration and more condensed form of recalcitrant H-L and F-L molecules than FW leachates. These findings demonstrate how fluorescence and UV absorption spectroscopy can be used as an indicator for monitoring the evolution of recalcitrant organic compounds (H-L and F-L substances) in leachates formed at different stages of waste biodegradation.

Abstract In this study, commercial baker's yeast (Saccharomyces cerevisiae) was employed as a novel inoculum for a membrane bioreactor (MBRy). It was applied to landfill leachate (LFL) treatment to remove recalcitrant organic compounds as well as for the assimilation of recalcitrant compounds, since yeasts have a high ability to break such compounds down. The MBR was inoculated with 10 g L−1 of commercial baker's yeast and was operated at a hydraulic retention time of 48 h and pH of 3.5. The specific air demand based on the membrane area (SADm) was maintained at 0.6 m3 h−1 m−2. The MBRy achieved chemical oxygen demand (COD), color, NH3, and humic substances removal of 68, 79, 68, and 50%, respectively. Furthermore, the MBRy showed lower fouling potential, which can be attributed to the low extracellular polymeric substances production, as the formation of a cake layer was the major mechanism of membrane fouling. The work demonstrated that novel MBR is a promising technology for treating recalcitrant landfill leachate.

Dihydroxybenzenes are able to reduce Fe(III) and promote the Fenton reaction in the presence of H2O2. The catechol/Fe(III)/H2O2 system has been successfully used to degrade different compounds, being more efficient than the Fe(II)-Fenton reaction. In this paper the possibilities for using the catechol-driven Fenton reaction to degrade recalcitrant compounds such as the Fe(III)-EDTA complex and veratryl alcohol are reviewed.

Chlorinated aromatic compounds are an important group of compounds. Many of them have been produced in large quantities and they are indispensable to technological and societal benefits. But regulatory agencies have tightened regulations on the use and release of chlorinated aromatic compounds because of the scientific understanding of their toxicity, persistence, behavior in the environment and their potential to cause adverse effects on the ecosystem and human health.
Pentachlorophenol (PCP), octachloronaphthalene and decachlorobiphenyl are all highly chlorinated aromatic compounds, of which, PCP has been used mainly as a biocide. Octachloronaphthalene and decachlorobiphenyl don't have practical use, but their congeners have been used widely as chemicals in industry. These compounds are toxic, recalcitrant and bio-accumulated within organisms. As the conventional treatment, incineration of these compounds can cause more serious problems, so that suitable alternatives need to be developed for their detoxification.
When compared with biodegradation or the thermal treatment of these compounds, chemical degradations have several merits. (Abstract shortened by UMI.)

Recalcitrant organic compounds remain a key challenge in landfill leachate management as they are resistant to microbial degradation and have potential to damage the water environment. Conventional leachate characterisation methods are time consuming and limited by their inability to provide compositional analysis. This research therefore investigates the characteristics of recalcitrant organic compounds in leachates and undertakes a feasibility study of the possible use of UV absorption and fluorescence spectroscopy for a rapid and economical compositional analysis of recalcitrant organic compounds. Two laboratory experiments are carried out in this regard. In one experiment, a laboratory scale aerobic biodegradation is carried out on four untreated and two treated leachate samples collected from two UK MSW landfills (Pitsea and Rainham), and leachates are characterised using conventional methods (COD and DOC) as well as UV absorption and fluorescence spectroscopy. It is found that the leachates which have low organic content are easily biodegradable whereas the leachates which have high organic content are not easily biodegradable. UV and fluorescence spectroscopy allow compositional analysis of recalcitrant organic compounds and show that humic and fulvic compounds are the key components of the recalcitrant organic compounds. A rapid biodegradability assessment of different leachates using these novel techniques is in agreement with conventional method showing that a rapid characterisation of leachates using spectroscopic methods is feasible. It is also found that organic compounds in these leachates are aromatic in nature and the leachates containing large amounts of aromatic compounds, condensed aromatic structures are difficult to degrade. In another experiment, the influence of the solid waste component on the development of recalcitrant organic compounds in leachates is investigated by carrying out an anaerobic biodegradation experiment for fresh waste, composted waste, newspaper waste and synthetic waste. Composted waste contributes significantly to the development of the recalcitrant compounds due to the removal of readily biodegradable organic compounds during composting and hence the increased proportion of biologically resistant compounds during the subsequent anaerobic biodegradation. Newspaper waste also contributes significantly to the presence of recalcitrant organic compounds due to the relatively less resistant cellulose and high lignin present in this waste. This research validates the application of UV and fluorescence spectroscopy for rapid on-site monitoring of landfill leachates that would help scientist and engineers to assess leachate quality, identify various organic compounds and to optimise leachate treatment processes. The analysis performed on Pitsea and Rainham leachates is a promising step towards developing a database of representative information of characteristics of recalcitrant organic compounds in leachates for different UK landfills. This research also provides an understanding of the composition of leachates from different wastes and it can be conclude that disposals enriched with composted and newspaper waste would favour the development of leachates with high concentrations and condensed aromatic structures of recalcitrant organic compounds in a landfill system

This study reviews catalytic ozonation AOPs and traditional ozone-based AOPs to compare their efficiency for degradation of ozone-recalcitrant compounds. With the world’s population increasing and water becoming a scarce resource, it is important to improve current water recycling methods. Recycling water will play a large role in accommodating the increasing demand, but it will also be necessary to be improve the level of treatment in order to account for emerging contaminants (ECs) such as pharmaceuticals and personal care products. Advanced oxidation processes (AOPs) have been developed to degrade ECs that are not effectively removed by conventional wastewater treatment. The goal of implementing AOPs is to promote the formation of hydroxyl radicals (•OH), which are stronger oxidants than ozone, to degrade recalcitrant compounds. Current AOPs under investigation include ozonation of metal and carbon-based catalysts, known as catalytic ozonation. Traditional ozone-based AOPs currently in use include UV combined with ozone (UV/O3) and hydrogen peroxide combined with ozone (H2O2/O3). Seventeen studies were reviewed to analyze the effectiveness of multiple carbon- and metal oxide-catalytic ozonation AOPs, compared to traditional AOPs. These studies varied in reactor type, water source, pH, catalyst pretreatment, inclusion of competitor species, and flow regime. The variety of testing conditions made comparison difficult, so all studies were compared based on contaminant removal efficiency and degradation rate, as well as general EC degradation and removal of TOC. The addition of metal oxides during ozonation consistently increased rate of removal and in some cases, even doubled the reaction rate. Catalytic ozonation consistently decreased total organic carbon (TOC) levels amongst multiple studies, even in the presence of competitor species. Future work should study the formation and subsequent breakdown of reaction intermediates, role of competitor species, and impact of sorption to the ozonation catalyst.

Neste trabalho foi estudada a remoção e degradação de alquilbenzeno linear sulfonado (LAS) em esgoto sanitário afluente da Estação de Tratamento de Esgoto Monjolinho do município de São Carlos-SP. Para isso, foi utilizado reator anaeróbio de leito fluidificado (RALF) em escala piloto com areia como material suporte. O reator foi operado durante 220 dias em TDH de 18±1,96h e temperatura mesófila. Foram realizadas análises físico-químicas e cromatográficas, tanto de caracterização do esgoto sanitário afluente, quanto no monitoramento do reator. Em relação ao esgoto sanitário observou-se 653,50 ± 169,30 mg.L-1 e 6,19 ± 3,25 mg.L -1 para DQO bruta e LAS, respectivamente. Em relação aos metais potencialmente tóxicos foram observados cádmio, chumbo, manganês, níquel e zinco, além de traços de ferro. Em relação aos compostos recalcitrantes foram observados no esgoto sanitário butil benzeno sulfonamida, ácido hexadecanóico, limoneno, terpineno, fenol, álcool feniletílico, indolizina, cafeína e isobutil octadecil ftalato. Durante o período de operação do RALF em fluxo contínuo observou-se 503,84 ± 187,06 mg.L-1 e 210,53 ± 78,37 mg.L -1 de DQO bruta afluente e efluente, respectivamente, e eficiência de remoção de 56 ± 14%. Em relação ao LAS foi observado 7,77 ± 3,06 mg.L-1 e 5,67 ± 2,84 mg.L-1 para o afluente e efluente, respectivamente, e eficiência de remoção de 28 ± 27%. Por meio do balanço de massa foi verificado que apenas 0,1% dessa remoção foi por adsorção. Observou-se pH efluente de 7,40 ± 0,32, alcalinidade total efluente de 233,40 ± 40,75 mgCaCO3 L-1, e ácidos orgânicos voláteis efluente de 57,64 ± 48,08 mg L -1.
In this work, it was studied the removal and degradation of linear alkylbenzene sulfonates (LAS) in a sanitary sewage effluent from the Monjolinho Sewage Treatment Station of the city of São Carlos-SP. For such, it was used a pilot scale anaerobic fluidized bed reactor (AFBR), filled with sand as support material. The reactor was operated with 18 hours of TDH and mesophilic temperature. Physicochemical and chromatographic analyzes were performed both in the characterization of the sewage inflow and in the monitoring of the reactor. The variation in concentration of COD and LAS were of 653,50 ± 169,30 mg L-1, and 6,189 ± 3,25 mg L-1, respectively. Regarding potentially toxic metals, cadmium, lead, manganese, nickel and zinc were observed, traces of Iron were also found. Regarding recalcitrant compounds was observed in sanitary sewage, butyl benzenesulfonamide, hexadecanoic acid, limonene, terpinene, phenol, phenylethyl alcohol, indolizine, caffeine and isobutyl octadecyl phthalate were observed. The AFBR was operated in a continuous stream during 220 days. During this period the COD concentration was 503.84 ± 187.06 mg L-1 and 210.53 ± 78.37 mg L-1, afluente and effluent, respectively, with a removal efficiency of 56 ± 14%. In regard to the surfactant LAS, was observed 7.77 ± 3.06 mg L-1 and 5.67 ± 2.84 mg L-1 a ffluent and effluent respectively, being the efficiency of removal of 28 ± 27%. When the mass balance was perform, it was possible to verify that only 0.1% of this LAS removal was by adsorption. The effluent pH remained stable, close to neutrality 7.40 ± 0.32, the total effluent alkalinity was 233.40 ± 40.75 mgCaCO3 L-1 and volatile organic acids 57.64 ± 48.08 mg L-1.

Els tanins són polifenols produïts per plantes que s'utilitzen en l'adobat vegetal. Aquests es diferencien de la majoria dels fenols naturals perquè fan precipitar les proteïnes i s'utilitzen en el procés d'adobament per unirse a les proteïnes del col·lagen de la pell de l'animal, fent que el cuir sigui més durador. Es tracta d'una substància de baixa biodegradabilitat, amb una elevada demanda química d'oxigen soluble. A més, la presència d'aquests tanins en grans concentracions poden inhibir el tractament biològic. Generalment aquest fragment soluble i inflexible dels efluents de les adoberies s'elimina mitjançant processos químics. Es per això que un tractament biològic que pogués eliminar-los eficaçment tindria avantatges tant ambientals com econòmics. D'aquesta manera els fongs podrien ser utilitzats al tractament d'aigües residuals d'aquest tipus d’indústria. Tot i així continua sent un desafiament important l'aplicació d'un bioreactor a base de fongs que, en operacions a llarg termini, tingui un rendiment similar en condicions estèrils i no estèrils. La present tesi s'ha centrat en desenvolupar i testejat diverses tècniques amb l'objectiu d'eliminar els tanins. Es fa mitjançant la creació d'un ecosistema dissenyat a base de fongs i bacteris. Aquest s'aplica a processos típics de tractament d'aigües residuals d'adoberies. Aspergillus tubingensis MUT 990 ha sigut la soca fúngica més adequada. S'han fet servir tant recerques bibliogràfiques com la pròpia experiència prèvia per dissenyar i construir reactors a escala laboratori (4 litres) i a escala pilot (1.5 m3). La soca fúngica es va immobilitzar en portadors cúbics i es va inocular en un nou reactor giratori de llit submergit. La primera prova en bioreactors es va dur a terme per avaluar l'efecte de la rotació i l'efecte de l'addició del co-substrat en l'eliminació dels tanins. La segona prova es va realitzar de forma paral·lela en dos reactors de llit submergit fix; el primer es va alimentar amb un taní condensat (Quebracho) i el segon amb un taní hidrolitzable (Tara). Tots dos es van inocular amb Aspergillus tubingensis. El temps de retenció hidràulic i la concentració de tanins en el medi es van anar modificant per maximitzar la capacitat d'eliminació i per analitzar la inhibició del substrat. Es va mantenir estable un biofilm en el primer reactor durant 180 dies d'operació. D'altra banda, en el segon reactor va haver un despreniment de biomassa durant la posada en marxa; després va créixer com un cultiu suspès durant el període operatiu (226 dies). L'eliminació de la demanda d'oxigen soluble va ser, sense l'addició de co-substrats, de fins el 53% i 90% en el primer i segon bioreactor respectivament. Les comunitats microbianes formades per fongs i bacteris dels reactors es van caracteritzar amb un anàlisi d'ADN. A més es va aplicar la respirometria heterogènia per avaluar l'activitat biològica del biofilm. Les dades obtingudes es van utilitzar per desenvolupar un model matemàtic i realitzar una caracterització cinètica i estequiomètrica de la biomassa. Es van establir experiments específics juntament amb un procediment respiromètric per a la biomassa fúngica. Els resultats a escala de laboratori es van utilitzar per dissenyar un reactor a escala pilot. Finalment, després d'una fase de posada en marxa, el reactor a escala pilot es va alimentar amb aigües residuals riques en tanins recollides d'adoberies. Al final de l'experiment, el biofilm era estable i s'havia aconseguit un exercici encoratjador. Creiem que els resultats obtinguts representen el primer pas per a una futura aplicació a escala real i aconseguir eficientment l'eliminació biològica de tanins en aigües residuals d'adoberies.
Los taninos son compuestos polifenólicos producidos por plantas que se utilizan en el curtido vegetal. Los taninos se diferencian de la mayoría de los fenoles naturales porque precipitan las proteínas y se usan en el proceso del curtido para unirse a las proteínas del colágeno de la piel del animal para hacer que el cuero sea más duradero. Representan una de las sustancias de baja biodegradabilidad en las aguas residuales de la curtiduría con una alta y recalcitrante demanda química de oxígeno soluble. Además en grandes concentraciones, dichos taninos pueden inhibir el tratamiento biológico. Este fragmento soluble y inflexible de los efluentes de las curtiduría generalmente se elimina mediante procesos químicos. Por tanto, un tratamiento biológico que pudiera eliminarlos eficazmente, tendría ventajas tanto ambientales como económicas. Los hongos podrían ser utilizados para el tratamiento de aguas residuales de la industria del curtido. La aplicación de un bioreactor a base de hongos que tenga un rendimiento similar en condiciones estériles y no estériles en operaciones de largo plazo sigue siendo una tarea desafiante. La presente tesis se ha centrado en desarrollar y probar técnicas para eliminar los taninos con un ecosistema diseñado a base de hongos y bacterias para su aplicación en trenes típicos de tratamiento de aguas residuales en las curtidurías. El Aspergillus tubingensis MUT 990 fue seleccionado como la cepa fúngica adecuada. La investigación bibliográfica y las experiencia previa se utilizó para diseñar y construir reactores a escala de laboratorio (4 litros) y piloto (1.5 m3). La cepa fúngica se inmovilizó en portadores cúbicos y se inoculó en un nuevo reactor giratorio de lecho sumergido. La primera prueba en bioreactores se llevó a cabo para evaluar el efecto de la rotación y la adición del co-sustrato en la eliminación de los taninos. La segunda prueba se realizó de forma paralela en dos reactores de lecho sumergido fijo; el primero se alimentó con un tanino condensado (Quebracho) y el segundo con un tanino hidrolizable (Tara). Ambos se inocularon con el Aspergillus tubingensis. El tiempo de retención hidráulico y la concentración de taninos en el medio se fueron variando para maximizar la capacidad de eliminación y para analizar la inhibición del sustrato. Se mantuvo estable una biopelícula en el primer reactor durante 180 días de operación. Por otro lado, en el segundo reactor hubo un desprendimiento de biomasa durante la puesta en marcha y luego creció como un cultivo suspendido durante el período operativo (226 días). La eliminación de la demanda de oxígeno soluble fue hasta del 53% y del 90% y se logró en el primer y en el segundo bioreactor respectivamente sin la adición de co-sustratos. Las comunidades microbianas de los reactores formadas por hongos y bacterias se caracterizaron con un análisis de ADN. Además se aplicó la respirometría heterogénea, para evaluar la actividad biológica de la biopelícula. Los datos obtenidos se utilizaron para desarrollar un modelo matemático y realizar una caracterización cinética y estequiométrica de la biomasa. Se establecieron experimentos específicos junto con un procedimiento respirométrico para la biomasa fúngica. Los resultados a escala de laboratorio se utilizaron para diseñar un reactor a escala piloto. Finalmente, después de una fase de puesta en marcha, el reactor a escala piloto se alimentó con aguas residuales ricas en taninos recolectadas en las curtiembres. Al final del experimento, la biopelícula era estable y se había logrado un desempeño alentador. Creemos que los resultados obtenidos representan el primer paso para una futura aplicación a escala real y lograr eficientemente la eliminación biológica de los taninos en las aguas residuales de las curtidurías.
I tannini sono composti polifenolici prodotti dalle piante e sono utilizzati nella concia al vegetale a scala industriale. I tannini si differenziano dalla maggior parte degli altri composti fenolici naturali per la loro capacità di far precipitare le proteine ​​e sono utilizzati nel processo di concia per legarsi al collagene delle pelli animali, al fine di renderle più resistenti e non putrescibili. I tannini sono una delle sostanze solubili a bassa biodegradabilità presenti nelle acque di scarico della concia e presentano un’elevata domanda chimica di ossigeno recalcitrante. Inoltre, ad elevate concentrazioni possono inibire i trattamenti biologici. Questa frazione recalcitrante e solubile delle acque di scarico della concia è solitamente rimossa tramite processi chimici. Pertanto, un trattamento biologico in grado di rimuovere efficacemente questa frazione presenterebbe vantaggi sia ambientali che economici. Nonostante le proprietà antimicrobiche dei tannini, esistono organismi in grado di usarli come substrato di crescita, la loro biodegradazione nell'ambiente è principalmente associata ai funghi piuttosto che ai batteri. I funghi quindi possono essere sfruttati per il biorisanamento delle acque reflue dell'industria conciaria. Tuttavia, in questa tipologia di biotecnologie ambientali, i funghi non riescono a competere con batteri. L'utilizzo di un bioreattore fungino, con simili prestazioni in condizioni sterili e non sterili in prove a lungo termine, rappresenta ancora un compito impegnativo. La presente tesi si è focalizzata nello sviluppo e sperimentazione di tecnologie atte a rimuovere i tannini sfruttando un ecosistema di funghi e batteri, il fine ultimo è stato quello di sviluppare un trattamento da integrare a quelli convenzionali per le acque reflue (condizioni non sterili). Il ceppo fungino Aspergillus tubingensis MUT 990 è stato selezionato come il più adatto per il presente studio. La letteratura di settore e le esperienze precedenti hanno fornito un importante contributo per la progettazione e costruzione dei reattori a scala di laboratorio (4 litri) e un reattore a scala pilota (1.5 m3). Il ceppo fungino selezionato è stato immobilizzato in supporti costituiti da cubi di schiuma poliuretanica ed è stato inoculato in un innovativo reattore a letto rotante e sommerso. La prima prova con i bioreattori ha avuto il fine di valutare l'effetto della rotazione e dell'aggiunta del co-substrato sulla rimozione del tannino. La seconda prova è stata effettuata in parallelo in due reattori, il primo è stato alimentato con un tannino condensato (Quebracho) e il secondo con tannino idrolizzabile (Tara), entrambi sono stati inoculati con Aspergillus tubingensis immobilizzato sul supporto sopradescritto. Il tempo di ritenzione idraulico e la concentrazione di tannino sono stati i principali parametri studiati per massimizzare la capacità di rimozione e per analizzare l'inibizione del substrato. Nel primo reattore si è mantenuto un biofilm stabile durante i 180 giorni di funzionamento. Nel secondo reattore invece si è verificato un distacco del biofilm e lo sviluppo di una biomassa in sospensione per tutto il periodo sperimentale (226 giorni). Nel primo reattore è stata raggiunta una rimozione della domanda chimica di ossigeno solubile del 53% e nel secondo reattore del 90%, in entrambi senza l'aggiunta di co-substrati. Le comunità microbiche dei reattori, costituite da funghi e batteri, sono state caratterizzate da un'analisi metagenomica. Inoltre, è stata applicata una tecnica innovativa, la respirometria eterogenea, per valutare l'attività biologica del biofilm. I dati ottenuti sono stati utilizzati per sviluppare un modello matematico e per eseguire una caratterizzazione dei parametri cinetici e stechiometrici della biomassa. Poiché in letteratura la respirometria e la modellistica sono scarsamente applicate alle biomasse fungine è stata messa a punto una procedura respirometrica ed esperimenti dedicati. I risultati delle prove di laboratorio sono stati impiegati per la progettazione del reattore a scala pilota. Infine, dopo una fase di avviamento, il reattore a scala pilota è stato alimentato con refluo conciario contenente un’elevata concentrazione di tannini. Al termine della sperimentazione il biofilm è rimasto stabile mostrando una buona capacità di rimozione. I risultati ottenuti rappresentano il primo passo per una futura applicazione, su scala reale, di efficace trattamento biologico delle acque reflue conciarie.
Tannins are polyphenolic compounds produced by plants that are used in the vegetable tanning of leather at an industrial scale. Tannins differ from most other natural phenols since they precipitate proteins and are used in the tanning process to bind to the collagen proteins of the animal skin to make leather more durable and not putrescible. Tannins represent one of the low-biodegradability substances in tannery wastewaters with a highly recalcitrant soluble chemical oxygen demand; moreover, at high concentrations they can inhibit biological treatment. This soluble recalcitrant fraction of tannery effluents is usually removed by means of chemical processes. Therefore, a biological treatment that could remove effectively this fraction would have both environmental and economic advantages. Despite the antimicrobial properties of tannins, there are organisms that are able to grow on them; in fact their biodegradation in the environment is mainly associated with fungi rather than bacteria. Fungi could thus be exploited for the bioremediation of wastewater streams of the tanning industry. However, in environmental biotechnology applications, fungi tend to be outcompeted by bacteria. The application of a fungal-based bioreactor, that has a similar performance under sterile and non-sterile conditions in long-term operations, is still a challenging task. The present thesis was aimed at developing and testing technologies to remove tannins with an engineered ecosystem based on fungi and bacteria for application in typical tannery wastewater treatment trains (non-sterile conditions). Aspergillus tubingensis MUT 990 was selected as a suitable fungal strain. Literature research and previous experiences were used to design and build lab-scale (4 litres volume) and pilot-scale (1.5 m3 volume) reactors. The selected fungal strain was immobilised in polyurethane foam cubes carriers and inoculated in a novel rotating, submerged, packed bed reactor. The first test in bioreactors was carried out to evaluate the effect of rotation and the co-substrate addition on tannin removal. The second test in bioreactors was carried out in two submerged packed bed reactors run in parallel, the first one was fed with a condensed tannin (Quebracho tannin), and the second with hydrolysable tannin (Tara tannin), both were inoculated with Aspergillus tubingensis in attached form. The hydraulic retention time and the concentration of tannins in the medium were varied to maximise the removal capacity and to analyse the substrate inhibition. A stable biofilm was maintained in the first reactor during the 180 days of operation. On the other hand, in the second reactor there was a biomass detachment during the start-up and then grown as a suspended culture throughout the operational period (226 days). Soluble chemical oxygen demand removal up to 53% and 90% were achieved in the first and second bioreactor, respectively, without the addition of co-substrates. The microbial communities of the reactors, made up of fungi and bacteria, were characterised with a metagenomic analysis. In addition, an innovative technique, the heterogeneous respirometry, was applied to assess the biological activity of immobilised cells (biofilm). The data obtained were used to develop a mathematical model and to perform a kinetic and stoichiometric characterisation of the biomass. Since fungal biomass is poorly characterised with modelling and respirometry, dedicated experiments were set-up along with a respirometric procedure. The lab-scale results were used to design a pilot-scale reactor. Finally, after a start-up phase the pilot-scale reactor was fed with real tannin-rich wastewater collected from tanneries. At the end of the experimentation the biofilm was stable and an encouraging performance had been achieved. We believe the results obtained represent the first step for a future real-scale application to reach an efficient biological removal of tannins from tannery wastewater.

This thesis presents the design and analysis of photo-electro catalytic oxidation technology for its potential use in water treatment applications. Doping titanium dioxide can effectively improve oxidative reactions. Using minute reactor design adjustments, such as electrolysis, the bases of degrading soluble organic compounds can be improved within the reactor. Applications of doping and secondary catalysis are effective in increasing the process of photoactivity within the catalytic reactor, theoretically increasing the production of sacrificial electron acceptors. Higher degradation's were accomplished using doped chromium titanium dioxide photocatalyst, which degraded significantly larger amounts of organics compared with pure titanium dioxide. Techniques used to accomplish the increased photo-reactivity were doping chromium (III) ion into titanium dioxide crystal lattices and silver ions into the photocatalytic coat. Degradation curves were determined by total organic carbon and the chemical oxygen demand. Calculations of the final rate constants show that lighter molar concentrations have higher rates of degradation.

This thesis reports on the degradation of two different models of organic pollutants in two contrasting Scottish river sediments. The first type of sediment (sediment 1) was collected close to an urban area with high percentage of organic matter content (1.3%). The second type of sediment (sediment 2) was collected from a pristine area and was less organic (0.2%). As organic pollutant model, radiolabelled (14C) 2,4-Dichlorophenoxyacetic acid (Acid-ring-UL-14C) and Naphthalene (Naphthalene-1-14C) were amended to individual microcosms (50g of sediment and 50ml of river water) at different concentrations (0.5, 5.0 and 50 mg per microcosm). Degradation was assessed by emission of 14CO2 during a period of 40 and 124 days for 2,4-D and Naphthalene, respectively. 2,4-D was mostly degraded between 20-35 days, and degradation rates (5 to 750 mgd-1) were proportional to initial concentrations. Almost 25% of applied Naphthalene was degraded by 40 days, at different degradation rates (2.7 to 405 mgd-1) according to sediment type. Assessment of the impact of 2,4-D and Naphthalene on the sediment microbial community was made using Biolog, DGGE and PLFA analysis to provide for a comparative physiological, molecular and chemotaxonomic assessment, respectively. These analyses linked differences in the rates and extents of 2,4-D degradation to differences in composition of the microbial communities. To assess the impact of 2,4-D, DGGE-profiling was used and show genetic changes were more significant in sediment 2 microcosms than sediment 1. Biolog suggested differences in the microbial structure of both sediments, but PLFA demonstrates that sediment 1 treatments were more affected by 2,4-D amendments than sediment 2. The extent of Naphthalene biodegradation was restricted by bioavailability, sediment type and volatilisation.

Objetivou-se neste trabalho avaliar a remoção e degradação de surfactante aniônico alquilbenzeno linear sulfonado (LAS) em esgoto sanitário do município de São Carlos – SP empregando o reator anaeróbio de leito granular expandido (EGSB - Expanded Granular Sludge Bed) em escala piloto, com TDH de 36 horas e temperatura mesofílica (±35ºC), instalado na ETE de São Carlos. Análises físico-químicas e cromatográficas foram realizadas para a caracterização do esgoto sanitário e monitoramento do reator EGSB. Foi observado no esgoto sanitário concentração de DQO bruta e LAS de 653,50 ± 169,30 mg L-1 e 6,189 ± 3,25 mg L-1, respectivamente. Em relação ao Ferro e metais potencialmente tóxicos, foram observados no esgoto sanitário os seguintes compostos: Cádmio, Chumbo, Ferro, Manganês, Níquel e Zinco. Em relação aos compostos recalcitrantes foram observados Butil Benzenosulfonamida, Ácido Hexadecanóico, Limoneno, Terpineno, Fenol, Álcool Feniletílico, Indolizina, Cafeína e Isobutil Octadecil Ftalato. O reator EGSB foi monitorado durante 314 dias e observou-se para DQO afluente e efluente, respectivamente, 265,82 ± 82,36 mg L-1 e 63,24 ± 40,67 mg L-1. Em relação ao LAS observou-se 7,35 ± 3,76 mg L-1 e 3,32 ± 3,08 mg L-1, respectivamente. Verificou-se 60,37 ± 29,84% de remoção de LAS. Observou-se durante toda operação pH próximo a neutralidade (7,26 ± 0,31), alcalinidade total efluente de 234,61 ± 64,39 mgCaCO3 L-1 e ácidos orgânicos voláteis efluente de 88,26 ± 23,68 mg L-1. Por meio do balanço de massa constatou-se que 56,2% do LAS foram removidos, compreendendo 12,8% por adsorção e 43,4% por biodegradação. Ao longo da operação do EGSB observou-se desestruturação e diminuição do tamanho médio dos grânulos, tal fato corrobora com a maior concentração efluente de sólidos totais e sólidos totais voláteis no primeiro mês e ao final da operação em comparação com a média geral de sólidos efluentes. Foram identificados por meio da plataforma Illumina MiSeq, 18 gêneros relacionados a degradação do LAS, tais como Synergistes, Syntrophorhabdus, Syntrophus, Clostridium, Geobacter e Desulfovibrio.
This study purpose was to evaluate the Anionic Surfactant Linear Alkylbenzene Sulfonate (LAS) in sanitary sewage from the city of São Carlos using an anaerobic expanded granular sludge bed reactor (EGSB), at pilot scale, with 36 hours TDH and (± 35ºC) mesophilic temperature, installed at São Carlos wastewater treatment station. Physical-chemical and chromatographic analyzes were performed for sanitary sewage characterization and EGSB reactor monitoring. It was observed an amount of 653,50 ± 169,30 mg L-1 in the raw sewage COD and an amount of 6,189 ± 3,25 mg L-1 in LAS. Regarding the potentially toxic metals, the following compounds were observed in the sanitary sewage: Cadmium, Lead, Iron, Manganese, Nickel and Zinc. Concerning recalcitrant compounds, Butyl Benzenesulfonamide, Hexadecanoic Acid, Limonene, Terpinene, Phenol, Phenylethyl Alcohol, Indolizine, Caffeine and Isobutyl Octadecyl Phthalate were observed. The EGSB reactor was monitored for 314 days and was observed for affluent and effluent COD, respectively, 265.82 ± 82.36 mg L-1 and 63.24 ± 40.67 mg L-1. In relation to LAS, were observed 7.35 ± 3.76 mg L-1 and 3.32 ± 3.08 mg L-1, respectively. There was 60.37 ± 29.84% LAS removal. It was observed, during the whole operation, pH close to neutrality (7.26 ± 0.31), total effluent alkalinity of 234.61 ± 64.39 mg.CaCO3.L-1 and volatile organic acids effluent of 88.26 ± 23, 68 mg L-1. By mass balance it was verified that 56,2% of the LAS were removed, comprising 12,8% by adsorption and 43,4% by biodegradation. During the EGSB operation, it was observed a disintegration and a decrease in the average granules size, fact that corroborates with higher total solids effluent concentration and total volatile solids in the first month and at the end of the operation compared to general effluent solids average. 18 genres related to LAS degradation were identified through the Illumina MiSeq platform, such as Synergistes, Syntrophorhabdus, Syntrophus, Clostridium, Geobacter and Desulfovibrio.

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Made available in DSpace on 2015-07-06T14:05:57Z (GMT). No. of bitstreams: 1 Elisa Kerber Schoenell.pdf: 1100203 bytes, checksum: 7fc798f66b493b73d31a96dbbf676ff3 (MD5) Previous issue date: 2013-02-28
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
CNPQ – Conselho Nacional de Desenvolvimento Científico e Tecnológico
FINEP - Financiadora de Estudos e Projetos
Ministério da Ciência e Tecnologia
Os lixiviados são efluentes gerados em depósitos de resíduos sólidos, através da decomposição da matéria orgânica, somados as águas de infiltração e a materiais suspensos. Ele possui compostos biodegradáveis e recalcitrantes - de difícil degradação biológica (biodegradação). Este efluente necessita de um tratamento antes de ser disposto no meio ambiente. O objetivo deste trabalho foi avaliar o uso de ozônio (O3) e peróxido de hidrogênio (H2O2) como processo oxidativo avançado (POA), visando a remoção de compostos recalcitrantes em lixiviados de aterros sanitários. Foram utilizados dois lixiviados provenientes do aterro sanitário de São Leopoldo/RS: bruto e tratado por lagoas, os quais foram tratados apenas por O3 em concentração de 29 mg/L (gerados a partir de processo corona) ou com adição de 1000 mg/L de H2O2 ao O3. Os ensaios ocorreram em escala piloto, sendo tratados 460 L de lixiviado em cada ensaio, os quais tiveram duração de 96 horas. O POA (operando com os oxidantes O3 e O3 + H2O2) mostrou-se mais eficiente no tratamento de lixiviados que tiveram as menores concentrações iniciais de DBO, DQO e COT, independente de ser lixiviado bruto ou tratado. Altas remoções de cor aparente, DQO e COT foram observadas, chegando a 99%, 88% e 66%, respectivamente. A maior remoção de carbono inorgânico foi 23%, porém o grupo que iniciou com a maior concentração desse parâmetro, obteve as maiores remoções para todos os outros parâmetros estudados. A adição de H2O2 aumentou a eficiência de remoção de todos os parâmetros analisados, porém não de forma significativa. Observou-se necessidade de tratamento complementar ao POA deste estudo.
Leachates are wastewaters generated at sites of solid waste disposal through organic matter decomposition, added to infiltration waters and suspended materials. It contains biodegradable and recalcitrant compounds - difficult to biological degradation (biodegradation). This wastewater requires treatment before being disposed in the environment. The aim of this study was to evaluate the use of ozone (O3) and hydrogen peroxide (H2O2) as advanced oxidation process (AOP), in order to removal recalcitrant compounds in landfill leachate. It was used two leachates from São Leopoldo/RS landfill: raw and treated in pounds, which were treated only with O3 at a concentration of 29 mg/L (generated from the corona process) or with addition of 1000 mg/L H2O2 to O3. The tests occurred on a pilot scale, treating 460 L of leachate in each test, which lasted 96 hours. OAP (operating with the oxidants O3 and O3 + H2O2) was more efficient in the treatment of leachate that had the lowest initial concentrations of BOD, COD and TOC (both raw and treated leachate).. High removals of apparent color, COD and TOC were observed, reaching 99%, 88% and 66%, respectively. The greater removal of inorganic carbon was 23%, but the group that started with the highest concentration of these parameter, achieve the greatest removals for all others parameters studied. The addition of H2O2 increased the efficiency of removal of all parameters, but not significantly. It was observed need of additional treatment to the POA of this study.

Soils containing inorganic compounds are frequently encountered by transportation agencies during construction within the right-of-way, and they pose a threat to human health and the environment. As a result, construction activities may experience project delays and increased costs associated with management of inorganic compounds containing soils required to meet environmental regulations. Recalcitrance of metal-contaminated soils toward conventional treatment technologies is exacerbated in clay or organic content-rich fine-grained soils with low permeability and high sorption capacity because of increased treatment complexity, cost, and duration. The objective of this study was to develop an accelerated in situ electrochemical treatment approach to extract inorganic compounds from fine-grained soils, with the treatment time comparable to excavation and off-site disposal. Three reactor experiments were conducted on samples collected from two borehole locations from a field site in Illinois that contained arsenic (As)(~7.4 mg/kg) and manganese (Mn)(~700 mg/kg). A combination of hydrogen peroxide (H2O2) and/or citrate buffer solution was used to treat the soils. A low-intensity electrical field was applied to soil samples using a bench-scale reactor that resembles field-scale in situ electrochemical systems. For the treatment using 10% H2O2 and citrate buffer solution, average removal of 23% and 8% were achieved for Mn and As, respectively. With 4% H2O2 and citrate buffer, 39% and 24% removal were achieved for Mn and As; while using only citrate buffer as the electrolyte, 49% and 9% removal were achieved for Mn and As, respectively. All chemical regimes adopted in this study reduced the inorganic compound concentrations to below the maximum allowable concentration for Illinois as specified by the Illinois Environmental Protection Agency. The results from this work indicate that electrochemical systems that leverage low concentrations of hydrogen peroxide and citrate buffer can be effective for remediating soils containing manganese and arsenic.