Biofouling in reverse osmosis (RO) occurs when bacteria settle in the elements and start building a biofilm.This paper highlights the performance of a new generation of fouling-resistant RO element, the newly developed FilmTec™ SW30XFR-400/34 seawater fouling-resistant membrane element in terms of its biofouling resistance.Additionally, this paper presents a validation of the product at a realistic scenario: the Middle East Red Sea.The validation trials proved the robust performance that this new membrane element shows under harsh biofouling conditions.This membrane element is able to offer 34% lower pressure drop than previous generations with a stable performance in terms of normalized permeate flow and salt rejection.In the validation trials this feature led to a significant reduction of the chemical cleanings (CIP) caused by biofouling; more than 33% reduction of the annual CIP frequency.Additionally, thanks to the membrane chemistry robustness, one of the FilmTec™ brand essence attributes, the product is able to offer advantaged chemical resistance when chemical cleanings are performed.Under the same conditions, where an element from another membrane manufacturer is experiencing 85% increase in salt passage, FilmTec™ SW30XFR-400/34 shows stable performance.

Hydroponics culture greenhouses usually work in closed and semi-closed irrigation systems for nutrients and water-saving purposes. Photo-Fenton reaction has been revealed as an efficient way to depollute that kind of recycled effluents containing pesticides, even for high salinity concentrations. However, the inefficacy of organic matter chemical depletion imposes the use of a subsequent treatment. This work proposes the suitability of an integration of advanced oxidation process with a subsequent bioreactor to treat greenhouse lixiviates effluents at high or extremely high conductivity (salts concentration: up to 42 g L⁻¹). As a first step in this study, the performance of a series of sequencing batch reactors was monitored in order to check the biocompatibility of photo-Fenton pretreated effluents depending on their salinity content. In the second step, those same pretreated effluents were loaded to a biofiltration column filled with expanded clay. Finally, bacterial 16S rRNA gene sequencing was carried out to analyse microbial diversity of the biomass developed in the column. Results stated that the chemical-biological coupled system is effective for the treatment of water effluents containing pesticides. The integrated system is able to deplete more than 80% of the organic load, even under extremely high salinity.

Interferences from many sources can affect photo-Fenton reaction performance. Among them, catalyst inhibition can be caused by the complexation and/or precipitation of iron species by the organic matter and salts present in the reaction media. This is the case of the oxidation of effluents containing organophosphorous fosetyl-Al. The degradation of this fungicide generates phosphate anions that scavenge iron and hinder Fe(II) availability. Experimental design was applied to artificially enlighten photo-Fenton reaction, in order to evaluate fosetyl-Al degradation. The performed experiments suggested how iron inhibition takes place. The monitoring of photo-Fenton reaction over a mixture of fosetyl-Al with other two pesticides also showed the interferences caused by the presence of the fungicide on other species degradation. Solar empowered photo-Fenton was also essayed for comparison purposes. Artificial and solar light photo-Fenton reactions were revealed as effective treatments for the elimination of tested fungicide. However, the phosphate ions generated during fosetyl oxidation decreased iron availability, what hampered organic matter degradation.

The performance of the photo-Fenton reaction under high salinity conditions (up to 50mScm−1) has been tested regarding the oxidation of two pesticides, imidacloprid and methomyl, in the shape of their commercial formulations. In opposition to what is commonly outlined in the literature, an enhancement in pesticides depletion has been found due to the positive participation of halogen radicals, Cl. However, this beneficial effect does not improve organic carbon elimination but rather displays worse total organic carbon (TOC) depletion. This effect is most likely due to the hydroxyl radicals scavenging and the complexation of Fe3+ by chloride salts, which reduce the availability of reagents. Although salts/Fe3+ interaction was observed, Fe3+ interaction with the organic content was revealed as more relevant, especially for imidacloprid.

The aim of this work was the study of degradation of a commercial polyamide membrane by two commonly employed oxidants for disinfection in seawater desalination, hypochlorite, and chlorine dioxide. A conventional reverse osmosis (RO) membrane is a thin film composite membrane composed of three different layers, a polyester support web, a microporous polysulfone interlayer, and a thin cross-linked polyamide barrier layer on the top surface, which is the active layer of the RO membrane. The degree of membrane degradation in seawater was evaluated in terms of decline in membrane performance calculated from permeability and salt rejection. In order to establish a relationship between the hydraulic properties and spectroscopic data, infrared and X-ray photoemission techniques (ATR-FTIR and XPS) were employed. The obtained results were compared with the Fujiwara test which is usually performed in membrane autopsies to check the degradation of polyamides with halogens. The chemical degradation of the surface active layer was analyzed using infrared spectroscopy (ATR-FTIR) by monitoring the changes in the characteristic infrared bands of the polyamide. It is possible to calculate the transmittance bands ratio between peak at 1540 cm(-1) (due to amide II) and peak at 1585 cm(-1) (due to the polysulfone layer) in order to get the comparison of the degraded membranes with a virgin membrane. The amide II band was selected to evaluate the degradation process, because it is the first band that reduces its transmittance value when the degradation process begins. Once the ratio is obtained for the degraded membrane and considering the value obtained from the virgin membrane as the reference point, a new index is calculated named as degradation index. The higher the parameter is, the greater the chemical attacks the polyamide layer. X-ray spectroscopy (XPS) measures the elemental composition and the chemical state of the elements that exist in the surface of a solid. Evaluation of the binding energy is possible to determine if the halogens are attached to the polyamide structure. It was concluded in this work that both spectroscopic techniques ATR-FTIR and XPS could detect the membrane degradation process earlier than Fujiwara test.

The Advanced Oxidation Processes (AOPs) UV/H2O2 and ozonation are widely recognized reclamation treatments. During the oxidation processes, effluent organic matter is modified and broken down into smaller compounds, which affect the characteristics of the treated effluent. In this study, Dissolved Organic Matter (DOM) present in two secondary effluents from a Conventional Activated Sludge (CAS) and a Membrane Biological Reactor (MBR) system, was characterized and monitored during UV/H2O2 and ozonation reactions with the Liquid Chromatography – Organic Carbon Detector (LC-OCD) technique. The following DOM fractions were quantified: biopolymers, humic substances, building blocks, Low Molar Mass (LMM) neutrals and LMM acids. Although both technologies were efficient for nearly eliminating the entire DOM at extended oxidation conditions, some differences were observed between them. The two processes were effective in degrading biopolymers since the early stage of oxidation. In addition, ozonation, by dominant direct attack, was effective in eliminating humics and the other oxidation byproducts, with the exception of LMM acids, which were accumulated from the beginning of the reaction. For MBR effluent and high doses of oxidant, the exclusive presence of LMM acids confirmed their recalcitrance to ozonation. On the contrary, the radical non-selective oxidation mechanism of UV/H2O2 resulted in final CAS and MBR effluents in which the humic substances and all of the LMM compounds were present. Furthermore, monitoring of the organic matter fractions with LC-OCD demonstrated that the reduction of effluent aromaticity (decreasing in Specific UV Absorbance (SUVA)) was not strictly correlated with the complete depletion of humic substances in the effluents for both advanced treatments.

This work is focused on the study of the suitability of the photo-Fenton process as a pretreatment for water highly contaminated with a methomyl commercial formulation in Advanced Greenhouses devices. Initial concentrations of reagents and pesticide were evaluated according to a central composite experimental design, with methomyl depletion and biocompatibility of the final effluent as response functions. A triad of optimal operation conditions could be determined, [Met.](0)=50 mg L(-1), [H(2)O(2)](0)=254 mg L(-1) and [Fe(2+)](0)=77 mg L(-1) for the best elimination yield and an acceptable BOD(5)/COD value, and initial concentration of methomyl can be established as the most important parameter for the performance of the treatment due to the limitations that impose on the hydrogen peroxide doses in the presence of the excipients of the commercial formulation.

So-called “Advanced Greenhouses” are a new approach to the concept of protected agriculture. Among other technological and structural improvements, these facilities give the possibility of recycling the irrigation surplus water, rich in lixiviates, salts, pesticides and its metabolites. After many cycles, the current is so concentrated on those substances that it becomes necessary for the presence of a membrane separation stage which brine, highly concentrated on those named pollutants, has to be treated before being sent to the public sewage system. Advanced Oxidation Processes, among other chemical treatments, can be considered an alternative to process this current effluent. In this work, concentrated aqueous solutions of methomyl as model pesticide (200 mg·L−1) have been subjected to two of those processes: ozonation and photo-Fenton reaction. Analysis of the elimination of the pesticide itself and the grade of mineralization achieved have shown how, while the ozonation is the most effective process decomposing the pesticide (eliminating the total concentration in 60 minutes), the photo-Fenton reaction mineralizes successfully the 40% of the total organic load (the ozonation only can cope with 20%) but only decompose a 40% of the pesticide. Evolution of biodegradability and toxicity of the effluent along both processes was also analyzed. Intermediates generated both by ozonation and photo-Fenton did not increase the biodegradability of the treated effluents. Nevertheless, while acute toxicity just after 15 minutes of treatment with ozone is notably higher than for raw solution, and it is maintained till the end of the experiment (120 min), though, toxicity along photo-Fenton reaction has two growing and decreasing regions, always shows lower values than the provoked during ozonation. None of the two assayed processes has been proved to increase biocompatibility of highly concentrated methomyl solutions.

In a previous work, a hybrid system consisting of an advanced oxidation process (AOP) named Photo-Fenton (Ph-F) and a fixed bed biological treatment operating as a sequencing batch biofilm reactor (SBBR) was started-up and optimized to treat 200 mg·L−1 of 4-chlorophenol (4-CP) as a model compound. In this work, studies of reactor stability and control as well as microbial population determination by molecular biology techniques were carried out to further characterize and control the biological reactor. Results revealed that the integrated system was flexible and even able to overcome toxic shock loads. Oxygen uptake rate (OUR) in situ was shown to be a valid tool to control the SBBR operation, to detect toxic conditions to the biomass, and to assess the recovery of performance. A microbial characterization by 16S rDNA sequence analysis reveals that the biological population was varied, although about 30% of the bacteria belonged to the Wautersia genus.

The aim of the present work is to study a coupled system to treat biorecalcitrant wastewaters. The combination consists of an advanced oxidation process (AOP) named photo-Fenton (Ph-F), which is a photochemical treatment and a sequencing batch biofilter reactor (SBBR). The synthetic wastewater used to optimise this process is a solution of 200 ppm of 4-chlorophenol (4-CP). The first part of the work is the study of the biodegradability enhancement achieved by the photochemical process, measured as the ratio between the biochemical oxygen demand (BOD5) and the chemical oxygen demand (COD). The second step is the start-up and optimisation of the biological process. The results showed that it is necessary to severely treat the toxic solution (with 500 ppm of [H2O2]0) in order to achieve more than 90% of TOC removal in the whole process. The photochemical and biological treatments lasted 50 minutes and 24 hours, respectively.

The existence or presence of diverse hydrocarbons and persistent pollutants in seawater or saline wastewater due to different industrial activities is considerable. The photo-Fenton process is suggested as a possible treatment, but the effect of salinity must be explored. An experimental design is carried out to elucidate the influence of NaCl on the efficiency of the process. According to the results, the global TOC removal is not influenced by the presence of chloride, but the process becomes much slower, even more than 10 times in some of the operating conditions. If solar irradiation is possible photo-Fenton seems a good option to treat polluted water with high salinity.

It has been demonstrated that Photo-Fenton process is feasible for the remediation of wastewater containing multiple organic pollutants. In order to promote its industrialization, control strategies have to be defined and tested. The objective of the present work is to describe a mathematical equation that fits the amount of COD abated regarding the dose Of H2O2. UVA Laboratory-scaled and solar up-scaled experiments are compared. Also two H2O2 Supply strategies are compared; one in which H2O2 is added at the beginning of an experiment; the second, H2O2 is added in doses through an experiment. According to the results, simple equations have been found to fit experimental COD degraded depending on the amount of H2O2 supplied. There is also a ratio of COD degraded per amount of H2O2 consumed that fits a wide range of operating conditions. The ratio is estimated to be 0.51 (mg O-2/mg H2O2) which can be considered as a stoichiometry of Photo-Fenton process in the current conditions.

The aim of the present work is to study the biodegradability enhancement of a wastewater containing a non-biodegradable compound, 4-chlorophenol (4-CP), using a so-called Advanced Oxidation Process (AOP) named Photo-Fenton (Ph-F). The location of this study is in a more complex project the aim of which is the connection of this AOP with a biological treatment. The parameters to be studied are the initial concentrations of Fe2+ and H2O2 and the operating temperature. The work was planned using an experimental design named Central Composite Design (CCD), in order to observe the effect of each factor on different responses, such as 4-CP removal, Total Organic Carbon (TOC) removal, Chemical Oxygen Demand (COD) removal, Biochemical Oxygen Demand (BOD5)/COD ratio evolution and total time until the total consumption of hydrogen peroxide. The operating conditions are optimized taking into account the operating costs. The results showed that Fe2+ and temperature do not affect the degradation and biodegradability enhancement results, but they affect significantly the time of the experiment, and consequently the operating costs.

Short peptides spanning the helicoidal sequences of the uteroglobin monomer (crystal forms P21 and C2221) were synthesized and studied by circular dichroism spectroscopy. None of them showed any secondary structure in the absence of HFIP. However, most peptides achieved a helical conformation when this structuring agent was used, with the exception of the analogue corresponding to the helicoidal fragment 19–24 (helix II, crystal P21). These results indicate that other factors, such as interchain interactions, have to contribute to helix stabilization in the molecule. On the other hand, while peptides corresponding to N- and C-terminal fragments that contain the first and fourth helices of the monomer, respectively (1–14 and 48–70) achieved a β-like structure when 10–15% of HFIP was used, this behaviour was not observed when TFE was used. Moreover, substitution of cysteine by α-aminobutyric acid at position 3 increased both the helicity of fragment 1–14 and its ability to adopt a β-like structure, but the opposite effect was observed for fragment 48–70 when α-aminobutyric acid was introduced at position 69. These results indicate that this part of the protein might be sensitive to the chemical environment it is exposed to and that the two cysteine residues at positions 3 and 69 of the monomer could play a different role in the folding process.