Comprising over 70% of the Earth's surface, water is undoubtedly the most precious natural resource that exists on our planet. Without the seemingly invaluable compound comprised of hydrogen and oxygen, life on Earth would be non-existent: it is essential for everything on our planet to grow and prosper. Although we as humans recognizethis fact, we disregard it by polluting our rivers, lakes, and oceans. Subsequently, we areslowly but surely harming our planet to the point where organisms are dying at a very alarming rate. In addition to innocent organisms dying off, our drinking water has become greatly affected as is our ability to use water for recreational purposes. In order to combat water pollution, we must understand the problems and become part of the solution.When is compared with other options of processing, biological treatment of residualwater is considered a cheap and attractive alternative to eliminate various types ofcontaminants. The effíciency of the biological process depends on many factors such asthe concentration of the contaminants, the chemical structure of the composed, the pHand the presence of inhibitory compounds in wastewater. Although some organic contaminants can be degraded through biological process, many other composed synthetic and natural are not biodegradable.On the hand, several chemical processes as advanced oxidation processes (AOP's) canbe use for mineralization of many organic contaminants. The doubt that presents theseprocesses is the use of expensive reagents. A potential viable solution proposed during last two decays is the combination of these processes with biological processing. In these combined processes, the chemical process would be utilized like pre-treatment step to enhance the biodegradability and elimínate the toxicity of the effluents, while the total mineralization would be completed in the biological process. For it, it is interesting to monitor the changes in the biodegradability of the effluents along thechemical process, this may be use to determine the optimum pre-treatment time. In the literature various indicators have been proposed to follow the biodegradability, where the ratios BOD5/COD and BOD5/TOC are the most utilized (BOD: Biological oxygen demand); COD: Chemical oxygen demand; TOC: total organic carbón). In general, are municipal wastewater was taken as reference values. Thus, it is considered that an effluent is biodegradable when the relation BOD5/COD is over 0.4 or BOD5/TOC over 1.0 (Metcalf & Eddy, 1985).The AOP's are defined like those processes that imply the generation of radicals highlyreagents (especially radical hidroxilo) in suffícient quantities. Although most organicmatter can be degraded by these processes, other compounds as the acetic acids,maleico and oxálico, acetona or cloroformo are not attacked by these radicals (Bigda,1995). The advantage of AOP's comes from the fact that radicals can be formed through different processes.In this study, AOP's based on photo-oxidation well be used for treatment of water contained Phenol and 2,4-dichlorophenol. In the first chapter of this work a general literature review the reactions are presented in which a series of methods for the treating refractory were proposed, among them is found the adsorption in active carbon, humid oxidation, supercritical oxidation, electrochemical oxidation, chemical oxidation in its two parts classics and advanced oxidation. For all, a small bibliographical search as well previous publication in elimination of phenol (POH) and 2,4-dichlorophenol(DCP) are presented. Moreover, it was presented a basic explanation of the characteristics of the biological processing and its operational types. At the end of this chapter, it has been introduced a figure (Figure 3.4) that shows a possible strategy to treat any type of wastewater depending on the organic load and the biodegradability.With respect to the results, the thesis present a framework of the combination of AOP's and biological treatment. In this case, synthetic residual water containing phenol (POH) and 2,4-diclorophenol (DCP) and textile dyes.These compound associates as contaminants in different types of water. They appear in different types of industrial effluents and included among the 130 priority contaminants gives by US EPA and theEuropean Union.A study of the behaviour of these substances for a possible biological degradation showed that all presented low biodegradability, and some as the DCP and textile dyes were inhibited for biomass. Thus, it was necessary to seek alternatives treatment processes.In a first part of this work, the degradation of these composed was studied by means ofadvanced oxidation processes (AOP's), based on the use of the process of photooxidation, in this case, direct irradiation with light UV or UVA, and combination thesesources of light with; UV(A)/H202, UV(A)/Fe(III),UV(A)/Fe(II)/H202 and the processFenton. These experiments were performed in four different, two of them are type tubular and the other two are type stirred tank. The followed variables along the process were the concentration of the contaminants, pH, initial concentration of the H202, Conc. Initial of Fe(II), time of irradiation and total organic carbon (TOC).The effect of irradiation time in the degradation of both the POH and DCP was studied. Also, kinetic of the reactions were followed. Results show that direct UV photolysis is not efficient for DCP and POH elimination. First order reaction constant of aprox.0.0056 min-1 and 0.0066 min-1 was obtained for POH and DCP, respect.)Also the combinations of this process with other hydroxyl radical sours were studied,for e. j., the effect of the quantity of peroxide or Fa(II), or the black light irradiationwith UV at (300-420 nm) vs. 254 nm. By means of the combination H202/UV/Fe removals percentages of 100 DCP and POH were achieved. During these reactions, by-products were identified, for POH it was identified caticlos, quinone and hidroquinoin. In the case of DCP, only it was possible to identify the clorobenzoquinona and some carboxylic acids.As it was mentiond above, the hostility that AOP's presents is use of expensive reagents, and a possible alternative is the combination with biological process. In this study also, some strategies for these types of combination have been established, that was possible by means of a study of the improvement in the biodegradability of the treated solutions. In a second part of the work, therefore, the effect of these processeswas studied in the biodegradability enhancement of the solutions. The better resultswere obtained by means of the process photo-Fenton, the ratios BOD5/COD increasedfrom O up to 0.92 and 0.48 for solutions of 100 ppm of POH and DCP respectively.After time of irradiation of 30 min and initial concentrations of H2 02 of 65 ppm and 300 ppm, respectively. Later the improvement of the biodegradability of the treated solutions, was studied the biodegradation of some solutions pre-tried of POH and DCP.Respect the DCP treated, the results have shown that activated sludge of a municipal wastewater plant could be adequate for the treatment of the pre-oxidize solutions and that was possible through co-digestion of the same with a residual water. By means of the combination photo Fenton -biological treatment. It was achieved up to a 89 of organic matter elimination. Continuing this line of investigation, it was developed alsoa complete combined processes consist of DCP pre-treated via Photo oxidation and aerobic and anaerobio biological reactors type SBR (sequencing batch reactor). By means of this process, elimination of organic matter up to 93 of TOC was obtained in a signifícant cycle time. The same strategy was applied to phenol, in this part a comparison has been established between single and coupled processes, the results havebeen shown that good improvement in organic matter take place in the combined processes.Finally, the use of the photo oxidation processes was examined to eliminate the colour and improvement the biodegradability of dyes solutions. The results have shown that these processes can be use efficiently for colour elimination and biodegradability improvement of dyes solutions.

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.

Advanced Oxidation Processes (AOPs) are suitable for achieving the complete mineralization of organic pollutants in wastewaters, since they are based on the generation of a powerful non-selective chemical oxidant. A major drawback of AOPs is that they involve high operating costs if high levels of mineralization are endeavoured. Integration of an AOP with a biological treatment has demonstrated to be a suitable alternative, since it combines the capacity of the AOP, in this case Photo-Fenton, to enhance biodegradability, with a biological treatment such as a Sequencing Batch Biofilter Reactor (SBBR), which operating costs are lower.Photo-Fenton (Ph-F) process is carried out by irradiating the system with ultraviolet (UV) and/or visible (Vis) light. In Fenton processes, by combination of hydrogen peroxide (H2O2) as a reagent and iron ions (Fe2+ for example) as catalyst in acid medium, highly oxidant species are generated.According to the results, most of the studied parameters may be written as a function of [H2O2]0, which means that temperature and [Fe2+]0 do not affect significantly the results. Moreover, a subsequent scale-up of the process shows that degradation follow very similar tendencies and shows similar results.It has been observed that the efficiency of oxidation follows a tendency directly related to the amount of H2O2 applied. An innovative description of the process is their modelling regarding the evolution of COD and BOD5 over the oxidation process or depending on the amount of H2O2 applied. The models show good fitting properties, and they appear to be a good basis for more precise modelling of the system.Regarding the integration of both processes, the best operating conditions consists of first treating the solution by Ph-F with 500 mg.L-1 of [H2O2]0 and 10 mg.L-1 of [Fe2+]0 at 27 ºC. The resulting product is then treated in the SBBR for 8 hours of time. More than 90 % of mineralization is achieved. The bioreactor show high resistance when is exposed to toxic shock load. Concerning control possibilities, monitoring the Oxygen Uptake Rate (OUR) by in-situ respirometry is suggested to be a good parameter, since it is a direct measurement of bacterial activity.

L’aigua és un bé escàs i finit, i degut a factors com l’increment de la població i el canvi climàtic, les previsions indiquen que a mig termini un 40% de la població viurà amb un estès hídric significatiu. Això podria tenir efectes molt greus en el desenvolupament i en el benestar a les àrees afectades. És normal doncs, que els darrers anys hagi acrescut considerablement l’interès en l’obtenció de recursos hídrics alternatius i sostenibles com la regeneració d’aigua i la reutilització. Els avenços tecnològics per al tractament d’aigües estan fent possible l’obtenció d’aigua regenerada de qualitat que pot ser utilitzada per a restauració ambiental, per al reg en general i per a usos urbans no potables. Tot i així, aquesta activitat podria suposar un perill per la presència de patògens d’origen entèric (bacteris, virus i protozous) i també per la presència de microcontaminants com productes farmacèutics, hormones o subproductes de desinfecció. El RD 1620/2007 estableix el marc legal de la reutilització, i es basa en E. coli com a indicador de qualitat microbiològica de l’aigua regenerada (AR). Tot i així, E. coli pot no ser suficient en relació a la presència de patògens vírics o protozous. Un exemple és Cryptosporidium, que s’ha convertit en un patogen de referència ja que ha causat nombrosos brots de criptosporidiosi d’origen hídric. L’ús de microorganismes indicadors alternatius com bacteriòfags (SOMCPH o FRNAPH) o espores de clostridis reductors del sulfit (SRC), pot ser molt útil per a indicar la presència o per modelar el comportament de patògens vírics o de protozous. En aquesta tesi s’estudia d’una banda, la qualitat microbiològica de l’AR que produeixen cinc plantes de tractament, analitzant E. coli, indicadors alternatius, i Cryptosporidium com a patogen de referència. Es fan assajos de QMRA lligats a Cryptosporidium en les EDARs estudiades, i finalment s’estudien les implicacions, d’un procés de reutilització per a augmentar el cabal del riu Llobregat uns Km més a munt del punt de captació de la potabilitzadora. Els resultats d’aquesta part indiquen que la reutilització per a potabilització en l’escenari estudiat, no hauria de suposar cap risc per a la salut de les persones des de la perspectiva de les malalties infeccioses. S’observa que l’ús d’un altre indicador, a part d’E. coli, significaria una millora en la gestió de l’AR ja que permetria fer un seguiment molt més acurat tant de la qualitat de l’aigua com de l’eficiència dels diferents tractaments. És recomanable l’ús de tractaments multibarrera durant la regeneració per poder garantir una aigua segura, i en aquest sentit, la inclusió de llum UV és vital en la prevenció del risc associat a Cryptosporidium en AR. D’altra banda s’estudien processos fotocatalítics d’oxidació avançada (POAs) com a processos de regeneració en l’eliminació de microorganismes d’efluents secundaris reals. D’una banda, amb l’ús de làmpades d’UV i de l’altra amb l’ús de la radiació solar com a font de llum UV. Per fer-ho es va analitzar la inactivació de diferents indicadors (SOMCPH, FRNAPH, CB390PH i SRC) davant alguns POA: H2O2/UV, TiO2/UV i foto-Fenton. Els resultats indiquen que l’ús de POA té un gran potencial com a tractaments terciaris en el futur, especialment si estan basats en la radiació solar, ja que podrien ser una opció ambientalment sostenible i alhora eficaç en el tractament d’aigua. Tot i així, és necessari segui investigant la possible aplicació d’aquestes tecnologies ja que encara hi ha certes limitacions que fan que de moment no es facin servir de manera més estesa. Finalment, els resultats pel que fa a la inactivació de microorganismes ratifiquen que l’ús d’un altre indicador seria útil per assegura la qualitat microbiològica de l’aigua. / Population growth and climate change may worsen the current water scarcity problems, which could have serious effects on the development and on the public health of the affected areas. Therefore, there is an increasing interest in the improvement of sustainable water resources such as water reclamation. Technological advances in water treatment are making it possible to obtain reclaimed water (RW), which can be used for instance, for environmental restoration or for irrigation. However, water reuse may represent a health risk due to the presence of enteric pathogens or micropollutants. Spanish regulations on RW are based on E. coli, but it may not be useful to protect against viral o protozoan diseases. Cryptosporidium has become a reference pathogen since it has caused numerous waterborne outbreaks. Thus, the use of alternative indicators such as somatic coliphages (SOMCPH) or spores of sulphite reducing clostridia (SRC) may be better to monitor presence and behaviour of certain pathogens. The aims of this thesis were: (i) to study the microbiological quality of RW analysing Cryptosporidium as the reference pathogen and different microbial indicators such as E. coli, SOMCPH and SRC; (ii) to perform QMRA analysis related to the presence of Cryptosporidium in RW; (iii) to analyse the implications of planned-IPR (indirect potable reuse) in the Llobregat River; (iv) to test the effect of different AOP (advanced oxidation processes) on indicator microorganisms for water reclamation purposes. From the infectious diseases point of view, the health risks due to waterborne pathogens linked to planned-IPR in the Llobregat River can be safely managed. Furthermore, the use of another indicator, besides E. coli, would improve RW management. Multi-barrier systems including UV for water treatment are recommended to ensure RW quality, especially with regard to Cryptosporidium inactivation. AOPs have a great potential for water reclamation in the future, especially those based on solar light, because they are sustainable and effective technologies for the removal of microorganisms as well as for the mineralisation of emerging micropollutants. Within the solar based procedures, photo-Fenton showed the best performance in microbial inactivation during the experiments. However, it is necessary to further investigate this AOP to overcome some of its actual limitations.