ENGLISH SUMMARY:In this work, the ozonation of emergent contaminants represented by pharmaceuticals (Sulfamethoxazole and Bezafibrate) and surfactants (Quaternary Ammonium Compounds) was studied. Results in terms of target compound degradation and mineralization along with the biodegradability and toxicity assessment of formed intermediates are presented. Moreover, a previous study about the suitability of the combination ozonation-Sequencing Batch Biofilm Reactor (SBBR), using the model compound 4-chlorophenol, is shown. The preliminary runs aimed to assess the mineralization of 100 and 200 mg L-1 4-chlorophenol (4-CP) solutions by ozonation and ozonation-biological treatment (SBBR). The experimental results showed that with an ozone flow rate of 5.44 and 7.57 g h-1, 4-CP was completely removed from the solution in 15 and 30 minutes of ozonation, respectively. By the other hand, at the 4-CP abatement time, on average only 26 % of total organic carbon (TOC) removal was achieved. The biodegradability (BOD5/COD) of the pre-ozonated solutions increased from 0 until a range between 0.2-0.37. The combination of ozonation and aerobic biological treatment in an aerobic sequencing batch biofilm reactor (SBBR) gave an abatement of more than 90 % of the initial TOC.The Quaternary Ammonium Compounds (QACs) ozonation was carried out in order to assess the mineralization potential of ozonation processes for this class of compounds. To perform this study, the QACs 16-BAC (Benzyl-dimethyl-hexadecylammonium-chloride) and 18-BAC (Benzyl-dimethyl-stearylammonium-chloride) were treated by ozonation at different O3 dosage. According to experimental results, from an initial TOC concentration of 50 mg L-1, 90 minutes of ozonation reached at most 50% of mineralization at the used conditions (ozone flow rate 7.57 g h-1). In order to observe the mineralization of QACs by means of photo-Fenton, the runs were carried out with the same QAC concentration used in ozonation runs. Besides, two different lamps were used (UV and Xe). According to experimental results, after 90 minutes of treatment, the photo-Fenton process achieved up to 80% of mineralization when the UV lamp was used. The efficiency of the photo-Fenton with Xe lamp was lower.To carry out the study of the sulfamethoxazole (SMX) ozonation, 200 mg L-1 SMX solutions were treated by ozonation at different pH. Results showed that ozonation was proved to be an efficient method to degrade sulfamethoxazole. After 15 minutes of ozonation (corresponding dose = 0.4 g of ozone L-1), the complete antibiotic abatement was almost achieved with just 10 % of mineralization. The biodegradability and toxicity of the ozonation intermediates were also studied. A biodegradability enhancement (increment of BOD5/COD ratio) from 0 to 0.28 was observed after 60 min of ozonation. The acute toxicity of the intermediates was followed by the Microtox® test and the toxicity profile showed a slight acute toxicity increment in the first stage of ozonation. The second order kinetic constants for the ozonation of the SMX in an order of magnitude of 105 L mol-1 s-1 were also determined for pH 5 and 7.Concerning the Bezafibrate (BZF) ozonation, the results showed that ozonation is an efficient method to degrade BZF: after 10 minutes of treatment (corresponding to a dose of 0.73 mmoles L-1 of ozone), the complete BZF abatement is achieved, starting from an initial concentration of 0.5 mmoles L-1. However, only a small part of the substrate is mineralized. The identification of main intermediates, attempted by HPLC-MS technique, indicates that the oxidation of BZF develops through both the hydroxylation of the aromatic ring and the attack of ozone on the unchlorinated aromatic one. The assessment of by-products biodegradability and acute toxicity demonstrates that ozonation is a suitable technique to improve the biodegradability and reduce the toxicity of waters containing BZF.

Les activitats de recerca destinades a la solució dels problemes de contaminació de les aigües estan patint un fort increment en els darrers anys. Entre les indústries més contaminants, cal esmentar la tèxtil i la paperera, i més concretament, els efluents provinents d´etapes deblanqueig. Quan els tractaments biològics convencionals d'aquests efluents contaminants no són efectius, la utilització de tecnologies emergents, tals com els processos d´oxidació avançada (AOP´s), basats en la formació in situ de radicals hidroxil, es mostra adient. Amb l´objectiu de provar la viabilitat de tractar efluents contaminants amb el radical hidroxil, vàrem triar l´ozonització i la fotocatàlisi per abordar efluents de blanqueig de pastes papereres generats en el laboratori. Aquesta prova mostrà que la fotocatàlisi pot reduir eficientment el contingut de carrega orgànica tot seguint una equació cinètica de Langmuir-Hinshelwood. A més, la combinació simultània de fotocatàlisi i ozonització produí un efecte sinèrgic que millorava el rendiment respecte al cas d´aplicar ambdós AOP´s de manera seqüencial.Tot i assumint que el radical hidroxil era l´oxidant adequat, planificàrem un extens estudi, fent servir aigües residuals industrials i distints AOP´s. La disminució del TOC i el cost en el tractament varen ésser els paràmetres contrastats en els distints estudis, amb l´objectiu de descobrir els principals avantatges i inconvenients de cada procés. El procés d´ozonització requeria disminuir el seu cost. La presència d´ions ferro en el procés ozó/UVA va aconseguir la reducció d´un 90% de TOC conjuntament amb una disminució del 15% en el cost. L´ús seqüencial de tractaments genera millors resultats (addició de ferro amb o sense llum, seguit per una etapa d´ozonització). Conclusions similars es varen obtenir en treballar amb una matriu sintètica de 2,4-diclorfenol (compost trobat usualment en els efluents de blanqueix de pasta de paper).Referent a la fotocatàlisi, s´ha posat de manifest la necessitat d´utilitzar una font de llum potent i/o la millora de l´eficiència de la llum incident en el catalitzador de TiO2. En aquest sentit vàrem provar dues vies: (a) la utilització d´un nou muntatge experimental amb una font de llum de 125 W. Determinacions d´AOX, toxicitat aguda, fenols i de GC-MS ens van portar a concloure que els compostos orgànics de clor eren eliminats eficientment en l´aigua residual. (b) la utilització de guies d'ones recobertes de TiO2. Solució que permet augmentar l´eficiència amb la que el catalitzador aprofita la llum incident per tal de millorar el disseny de reactors fotocatalitics.L´últim procés provat, el reactiu Fenton, en presència de llum solar o artificial, es va aplicar a la degradació d´efluents de blanqueig tèxtils o paperers. La degradació del contingut de càrrega orgànica d'aquests effluents s´assolia preferentment a pH = 3. El primer estudi es realitzà sobre un efluent de blanqueig de pastes de paper. La funció aproximada del sistema, estimada a partir del disseny experimental, mostrà que concentracions inicials inadequades de reactiu Fenton afectaven negativament al procés, a causa de reaccions competitives entre aquest i altres espècies oxidatives. Així mateix, la temperatura augmentà clarament les velocitats de la reacció, inclús sense presència de radiació. La millora en la disminució del TOC és particularment significativa quan les proporcions de reactiu Fenton són inadequades (en passar de 25 ºC a 40 ºC es pot aconseguir una reducció en el cost de l´ordre del 80%). Per altre banda, la llum solar aconsegueix reduir fins un 70 % el cost total d'un tractament de dues hores de durada. L'anàlisi de GC-MS constata l´eliminació dels compostos clorfenòlics. Un segon estudi sobre un efluent tèxtil corroborà la gran importància de la temperatura i de la presència de llum solar. En resum, tots els AOP´s provats mostren, sota condicions experimentals adequades, la capacitat de degradació del contingut orgànic present en efluents de blanqueig procedents d´indústries papereres i tèxtils. / There is an ever increasing amount of research activities especially devoted to the solution of water pollution problems.The pulp and textile industries are considered to be some of the largest polluters of all industries. The biggest problem with those industries consists in the polluted effluents discharged during the bleaching process because conventional biological treatments are not effective in treating these toxic pollutants. In these cases, the emerging technologies called Advanced Oxidation Processes (AOPs) represent an attempt to mineralize the contaminants by the in situ formation of hydroxyl radicals.In order to determine the effectiveness of treating effluents with the hydroxyl radical we chose the photocatalytic and ozonation processes to treat bleaching pulp effluents generated in the laboratory. Our results demonstrated that the photocatalytic process could efficiently reduce the organic content in accordance with the Langmuir-Hinshelwood kinetic equation. Moreover, simultaneously combining photocatalysis and ozonation provided a synergistic effect that was superior in performance to that of applying the photocatalysis and ozonation processes sequentially.Our tests with laboratory bleaching pulp effluents assumed that the hydroxyl radical was the proper oxidant to be use. An extensive study was undertaken using industrial wastewaters and different AOPs. TOC decay and treatment costs were the operative variables compared in the study in order to discover the benefits and shortcomings of each process.It is imperative that the ozonation process decreases the treatment costs. The addition of iron ions to bleaching mill wastewater undergoing ozone/UVA treatment resulted in high rates of TOC removal (90%) and in a significant cost reduction (15%). Additionally, sequential processing (stirred iron, with or without light irradiation, followed by an ozonation stage) led to even better results. Similar results were obtained on the synthetic sample of 2,4-dichlorophenol (a compound typically found in paper pulp bleaching effluents) investigated. We noticed that the photocatalytic process requires either a powerful light source or an improvement of the light utilization efficiency of the TiO2 catalyst, or maybe both, to be most effective. We tested two strategies: (a) A new experimental setup that used a high power light (125 W) to accelerate the reaction rate. AOX, acute toxicity, phenol and a GC-MS analysis led us to conclude that the chlorine organic compounds were efficiently eliminated from the treated wastewater. (b) The second approach consisted in using titanium dioxide (TiO2)-coated waveguides. This approach increases the light utilization efficiency of the TiO2 catalyst with the aim of improve the reactor's design.The last process that was tested involved the addition of Fenton reagent to the bleaching pulp and textile effluents in conjunction with either artificial or solar light The degradation of the organic contents was successfully performed at pH = 3.The first study was performed on bleaching pulp effluent. The approximate function of the system, as assessed by the experimental design, showed that initial non-optimum concentrations of the Fenton reagent were detrimental to the process because of competitive reactions of the Fenton reagent with oxidative species. On the other hand, temperature markedly increased the reaction rates, even without light irradiation. The improvement in TOC removal was particularly significant when the reagent ratios were not optimal. A decrease in cost around 80% is possible by just increasing the temperature from 25ºC to 40ºC. Moreover, solar light reduced the total cost of a two hour treatment by up to 70 % and efficiently removed the chlorophenolic compounds as shown by GC-MS analysis.The second study performed on textile wastewater corroborates the importance of the temperature parameter and the utility of solar energy. In summary, all AOPs tested displayed the capability to degrade the organic components of bleaching Kraft mill and textile mill effluents under suitable experimental conditions.