Desenvolupament d'un procés a escala pilot per al tractament del colorant tèxtil Gris Lanaset G amb Trametes versicolor

Consultable des del TDXTítol obtingut de la portada digitalitzadaEn aquest memòria es recullen els resultats més rellevants del treball experimental realitzat amb l'objectiu d'avançar en el coneixement per a desenvolupar un procés de tractament en continu de decoloració d'aigües residuals tèxtils utilitzant fongs ligninolítics. S'inicia el treball realitzant un estudi sobre les condicions d'operació per al tractament en continu d'una solució del colorant tèxtil Gris Lanaset G (complex organometal·lic) en un bioreactor fluiditzat per polsos d'aire amb el fong Trametes versicolor en forma de pèl·lets, establint la concentració de nutrients i el temps de residència hidràulic al qual s'ha d'operar per assolir percentatges de decoloració que compleixen la normativa d'abocament. Es proposa el mecanisme de decoloració, que té lloc en varies etapes en sèrie, primer es produeix l'adsorció inicial del colorant sobre la biomassa, posteriorment aquest es transfereix cap a l'interior de les cèl·lules, on es produeix el trencament del complex metàl·lic i finalment s'excreten al medi dels productes de degradació. Es determina el temps de residència cel·lular màxim en 40 dies i s'estableix la metodologia de renovació de biomassa en forma de pèl·lets per al tractament en continu. La renovació total de la biomassa es realitza en tres etapes, renovant un terç de la biomassa total del bioreactor en cada etapa, de manera que transcorregut un temps de residència cel·lular s'hagi renovat tota la biomassa del sistema. Es dissenya un reactor fluïditzat per polsos d'aire a escala pilot de 10 litres de volum útil i es realitza un estudi del comportament fluidodinàmic determinant el temps de mescla del sistema, i s'opera en discontinu i continu sense problemes operacionals. Un cop comprovada la bondat de l'escalat del bioreactor, s'introdueixen canvis paulatinament per adaptar el procés a condicions d'operació industrials, con són la no esterilitat de l'efluent a tractar, la supressió de macronutrients i micronutrients, la substitució de glucosa de qualitat anàlisi per glucosa de qualitat industrial, i així acabar tractant aigües residuals reals d'una indústria tèxtil sense esterilitzar on es posen de manifest alguns problemes que requeriran estudis posteriors. Donat que el procés d'eliminació de color més utilitzat a escala industrial és l'adsorció, s'estudia a escala laboratori l'adsorció del colorant Gris Lanaset G amb carbó actiu granular per tal de realitzar posteriorment un anàlisi comparatiu tant econòmic com ambiental dels dos processos, el d'adsorció i el biotecnològic. Aquests anàlisis posen de manifest que els costos d'operació del tractament biològic són únicament un 20% superiors que els costos d'operació del procés d'adsorció, i que aquest percentatge es podria reduir encara més trobant substrats alternatius a l'extracte de malta per la formació dels pèl·lets. També es posa de manifest que el procés biotecnològic és més sostenible que el procés d'adsorció, i per tant el procés biotecnològic és una alternativa interessant des de el punt de vista ambiental al tractament d'adsorció.In this work are shown the most important results obtained in the experimental studies done with the goal of improving in the knowledge to develop a continuous process treatment for the decolourisation of textile wastewaters by ligninolytic fungi. The work starts with an operation conditions study for the continuous treatment of the dye Gris Lanaset G, which is a textile metal-complex dye, in an air pulses fluidised bioreactor by the white root fungi Trametes versicolor in pellet morphology. The nutrients concentration is established, and the effect of the hydraulic residence time in the decolourisation percentages is evaluated, taking into account the accomplishment of the standards established. It is proposed the decolourisation mechanism, which presents tree steeps: first of all, the dye is adsorbed in the biomass, after the dye is transferred into the cells, where takes place the break down of the metal complex, and finally the degradation products are released to the liquid medium. The maximum cellular residence time is determined in 40 days, and the biomass renovation methodology is established for the continuous treatment. The total biomass renovation takes place in three steeps, renovating one third of the total biomass in the bioreactor in every steep, in such a way that in the course of one cellular residence time, all the biomass in the bioreactor has been renovated. A pilot scale air pulses fluidised bioreactor is designed with a 10 L working volume, and the fluidodimanic behaviour is studied, determining the mixing time of the system. Without having any operational problem, the batch and continuous operation is carried out successfully. Once it is checked the goodness of the system, some changes are introduced gradually to adapt the system to industrial conditions. The changes are: the non-sterility of the effluent, the suppression of macronutrients and micronutrients, and the substitution of analysis quality glucose by industrial quality glucose. Finally is carried out the treatment of non-sterile real textile wastewaters. The most used removal colour process at industrial scale is the adsorption, so the adsorption of the dye Gris Lanaset G in granular activated carbon (GAC) is studied. The goal of this study is to make a comparative economical and environmental analysis of the two processes, adsorption and biodegradation. These analysis show that the operational cost of the biologic treatment is only 20% more than the operational cost for the adsorption process. This percentage could be lower if an alternative substrate is found for the pellets formation. Also is showed that the biotechnological rocess is more sustainable than the adsorption one, so the biotechnological process is an interesting choice from the environmental point of view to the adsorption treatment

Effect of dissolved oxygen on the degradation activity and consumption capacity of white-rot fungi

Altres ajuts: acords transformatius de la UABIn recent decades, bioremediation using white rot fungi (WRF) has become an attractive alternative for the removal of xenobiotics from water. However, WRF are aerobic microorganisms whose degradative capacity may be reduced when operating in oxygen-restricted environments. This work determines the limiting dissolved oxygen level of Trametes versicolor in terms of degradation of two target micropollutants: bentazon and tributyl phosphate. When the dissolved oxygen concentration was set below 15 % saturation (1.3 mg O·L), the results revealed a considerable decrease in degradation capacity and laccase synthesis. Hence, 15 % dissolved oxygen was established as a reference value of aerobic conditions to assess dissolved oxygen profiles in both a rotating drum bioreactor (RDB) and a fixed-bed bioreactor (FBB). Restrictive oxygen conditions were achieved after an operating period of 24 h in the RDB and an empty bed contact time of 44 min in the FBB. In addition, growth kinetics on Q. ilex wood and organic matter removal (in terms of COD) were studied, obtaining 0.059 mg ergosterol·g wood DW·day and 16.23 mg O·L·h, respectively. Therefore, T. versicolor has demonstrated a remarkable ability to assimilate complex carbon sources and a high micropollutant degradation activity, especially when operating in non-limiting oxygen regimes

Bioremoval of humic acid from water by white rot fungi : exploring the removal mechanisms

Altres ajuts: This Research is part of research program "Increasing the utilization of organic waste and low value feeds with help of lignin degrading fungi" with project number 11611, and is supported by the Dutch Technology Foundation STW, which is part of the Netherlands Organisation for Scientific Research (NWO), and which is partly funded by the Ministry of Economic Affairs.Twelve white rot fungi (WRF) strains were screened on agar plates for their ability to bleach humic acid (HA). Four fungal strains were selected and tested in liquid media for removal of HA. Bioremediation was investigated by HA color removal and changes in the concentration and molecular size distribution of HA by size exclusion chromatography. Trametes versicolor and Phanerochaete chrysosporium showed the highest HA removal efficiency, reaching about 80%. Laccase and manganese peroxidase were measured as extracellular enzymes and their relation to the HA removal by WRF was investigated. Results indicated that nitrogen limitation could enhance the WRF extracellular enzyme activity, but did not necessarily increase the HA removal by WRF. The mechanism of bioremediation by WRF was shown to involve biosorption of HA by fungal biomass and degradation of HA to smaller molecules. Also, contradicting previous reports, it was shown that the decolorization of HA by WRF could not necessarily be interpreted as degradation of HA. Biosorption experiments revealed that HA removal by fungal biomass is dependent not only on the amount of biomass as the sorbent, but also on the fungal species. The involvement of cytochrome P450 (CYP) enzymes was confirmed by comparing the HA removal capability of fungi with and without the presence of a CYP inhibitor. The ability of purified laccase from WRF to solely degrade HA was proven and the importance of mediators was also demonstrated

Bioelectrochemically-assisted degradation of chloroform by a co-culture of Dehalobacter and Dehalobacterium

Using bioelectrochemical systems (BESs) to provide electrochemically generated hydrogen is a promising technology to provide electron donors for reductive dechlorination by organohalide-respiring bacteria. In this study, we inoculated two syntrophic dechlorinating cultures containing Dehalobacter and Dehalobacterium to sequentially transform chloroform (CF) to acetate in a BES using a graphite fiber brush as the electrode. In this co-culture, Dehalobacter transformed CF to stoichiometric amounts of dichloromethane (DCM) via organohalide respiration, whereas the Dehalobacterium -containing culture converted DCM to acetate via fermentation. BES were initially inoculated with Dehalobacter, and sequential cathodic potentials of −0.6, −0.7, and −0.8 V were poised after consuming three CF doses (500 μM) per each potential during a time-span of 83 days. At the end of this period, the accumulated DCM was degraded in the following seven days after the inoculation of Dehalobacterium. At this point, four consecutive amendments of CF at increasing concentrations of 200, 400, 600, and 800 μM were sequentially transformed by the combined degradation activity of Dehalobacter and Dehalobacterium. The Dehalobacter 16S rRNA gene copies increased four orders of magnitude during the whole period. The coulombic efficiencies associated with the degradation of CF reached values > 60% at a cathodic potential of −0.8 V when the degradation rate of CF achieved the highest values. This study shows the advantages of combining syntrophic bacteria to fully detoxify chlorinated compounds in BESs and further expands the use of this technology for treating water bodies impacted with pollutants

Fungal bioremediation of agricultural wastewater in a long-term treatment : biomass stabilization by immobilization strategy

Acord transformatiu CRUE-CSICFungal bioremediation emerges as an effective technology for pesticide treatment, but its successful implementation depends on overcoming the problem of microbial contamination. In this regard, fungal immobilization on wood seems to be a promising strategy, but there are two main drawbacks: the predominant removal of pesticides by sorption and fungal detachment. In this study, agricultural wastewater with pesticides was treated by Trametes versicolor immobilized on wood chips in a rotary drum bioreactor (RDB) for 225 days, achieving fungal consolidation and high pesticide biodegradation through two main improvements: the use of a more favorable substrate and the modification of operating conditions. Fungal community dynamic was assessed by denaturing gradient gel electrophoresis (DGGE) analysis and subsequent prominent band sequencing, showing a quite stable community in the RDB, mainly attributed to the presence of T. versicolor. Pesticide removals were up to 54 % diuron and 48 % bentazon throughout the treatment. Afterwards, pesticide-contaminated wood chips were treated by T. versicolor in a solid biopile-like system. Hence, these results demonstrate that the microbial contamination constraint has definitely been overcome, and fungal bioremediation technology is ready to be implemented on a larger scale

Enzymatic pretreatment of microalgae using fungal broth from Trametes versicolor and commercial laccase for improved biogas production

Es un article del grup de recerca BioremUAB (2014SGR476)Coupling microalgae production to wastewater treatment can reduce the costs of microalgae production for non-food bioproducts and energy consumption for wastewater treatment. Furthermore, microalgae anaerobic digestion can be enhanced by applying pretreatment techniques.. The aim of this study is to improve the biogas production from microalgal biomass grown in urban wastewater treatment systems by applying an enzymatic pretreatment with crude fungal broth and commercial laccase. To this end, the fungus Trametes versicolor was cultured, and the enzymatic activity of the culture broth analysed by measuring laccase concentration. The results showed that both the fungal broth and commercial laccase pretreatment (100 U/L) over an exposure time of 20 min increased the methane yield in batch tests. Indeed, the fungal broth pretreatment increased the methane yield by 74%, while commercial laccase increased the methane yield by 20% as compared to non-pretreated microalgal biomass. In this manner, laccase addition enhanced microalgal biomass anaerobic biodegradability, and addition of T. versicolor broth further improved the results. This fact may be attributed to the presence of other molecules excreted by the fungus

A comparison between biostimulation and bioaugmentation in a solid treatment of anaerobic sludge : drug contentent and microbial evaluation

Emerging pollutants can reach the environment through the sludge of Wastewater Treatment Plants. In this work, the use of Trametes versicolor in biopiles at lab-scale was studied, evaluating its capacity to remove the most hydrophobic Pharmaceuticals and assessing the evolution of the biopiles microbial communities. The total removal of drugs at real concentrations from sewage sludge was assessed for non-inoculated and fungal inoculated biopiles, testing if the re-inoculation of the biopiles after 22 days of treatment would improve the removal yields. It was found that 2 out of the 15 initially detected pharmaceuticals were totally degraded after 22 days, and re-inoculated fungal biopiles achieved higher removal rates than non-re-inoculated fungal biopiles for single compounds and for all the drugs simultaneously: 66.45% and 49.18% re-inoculated and non-re-inoculated biopiles, respectively. Finally, the study of the bacterial and fungal communities revealed that fungal inoculated and non-inoculated biopiles evolved to similar communities adapted to the presence of those drugs

Estudi per la selecció de CAG pel procés de potabilització de l'ETAP Ter

El present document representa l'estudi per la selecció de CAG pel procés de potabilització de l'ETAP Ter a partir d'un disseny experimental de planta pilot de menor escala. Es determina l'adequació de carbó en base a les característiques físiques (superfície BET, índex de iode...) i la capacitat d'eliminació de COT i UV respecte la mostra a tractar.The study of the selection of the GAC for the Ter water purification process has been carried out in this work, taking into account the results obtained in an experimental small-scale pilot plant. It has been determined the carbon suitability based on physical characteristics (BET surface area, iodine,..) and on the ability of the carbon for removing TOC and UV from the treated samples

Effect of cultivation conditions on β-estradiol removal in laboratory and pilot-plant photobioreactors by an algal-bacterial consortium treating urban wastewater

The use of microalgal consortia for urban wastewater treatment is an increasing trend, as it allows simultaneous nutrient removal and biomass production. Emerging contaminants proposed for the list of priority substances such as the hormone 17β-estradiol are commonly found in urban wastewater, and their removal using algal monocultures has been accomplished. Due to the inherent potential of algae-based systems, this study aimed to assess the capability of native photobioreactor biomass to remove 17β-estradiol under indoor and outdoor conditions. At the same time, the microbial community changes in regular and bioaugmented operations with Scenedesmus were assessed. The results show that almost complete removal (>93.75%) of the hormone 17β-estradiol can be attained in the system under favourable seasonal conditions, although these conditions greatly influence biomass concentrations and microbial diversity. Even under the harsh conditions of low temperatures and solar irradiation, the established consortium removed more than 50% of the pollutant in 24 h. While species from genus Chlorella were stable during the entire operation, the microbial diversity analysis revealed that assorted and evenly distributed populations stimulate the removal rates. Bioaugmentation assays proved that the input of additional biomass results in higher overall removal and decreases the yield per mg of biomass