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284 results on '"Gernjak, Wolfgang"'

51. Structural Characterization of Sol-gel TiO2 and CeO2 Coated Ceramics Membranes

Author

Tsiarta, Nikoletta, Panžić, Ivana, Bafti, Arijeta, Mandić, Vilko, Gernjak, Wolfgang, and Ćurković, Lidija

Subjects
Wastewater Reuse, Membrane Separation, Ceramic Membrane
Abstract

Wastewater reuse is considered as the most suitable and reliable alternative for sustainable water management and agricultural development [1] and membrane separation technology emerged as one of the tools to tackle the water stress problem. Ceramic membranes (CMs) offer durability and high integrity during filtration [2]. The most commonly used CMs for water treatment are alumina (Al2O3), titania (TiO2), zirconia (ZrO2), silicon carbide (SiC) and silica (SiO2) based. The structure and morphology of ceramic membranes have substantial effects on their performance. Based on their pore size, CMs could be classified into microfiltration (MF), ultrafiltration (UF) and nanofiltration (NF) with pore size ranging from > 50 nm, 2–50 nm and < 2 nm, respectively. In this study, four commercial CMs with different composition and pore size were used: three UF ceramic membranes of TiO2/ZrO2 composition with 50 kDa, 150 kDa and 300 kDa molecular weight cut-off (MWCO) respectively, and a MF ceramic membrane of TiO2/ZrO2+TiO2 composition with a pore size of 200 nm. The membranes were modified by sol-gel deposition of TiO2 [3] or CeO2 [4] film. One, two or three layers of each film were deposited on the each of the four membranes using the vacuum impregnation method to derive catalysts for application in hybrid ozonisationfiltration system. The composites were dried and subsequently thermally treated. Both the unmodified and surface-modified ceramics membranes were characterized in order to evaluate their chemical composition, phase composition, morphologic parameters, using scanning electron microscopy with energy dispersive X-ray spectroscopy, atomic force microscopy, nitrogen adsorption/desorption isotherms, X-ray diffraction analysis and Fourier transformed infrared spectroscopy.

Published
2021

52. A data-driven analysis of trace contaminants in wet-weather discharges

Author

Mutzner, Lena, Furrer, Viviane, Castebrunet, Hélène, Gernjak, Wolfgang, Gromaire, Marie-Christine, Matzinger, Andreas, Mikkelsen, Peter Steen, R. Selbig, William, and Vezzaro, Luca

Subjects
SDG 11 - Sustainable Cities and Communities
Abstract

Urban wet-weather discharges (combined sewer overflows, CSO and stormwater outlets from separate sewers, SWO) contain various trace contaminants which can pose a threat to receiving waters (Launay et al., 2016; Mutzner et al., 2020; Wicke et al., 2021). Hence, there is a need to identify critical contaminants and to quantify pollutant concentrations in wet-weather discharges to assess effective control strategies. Efforts have been made in the last decade to increase our understanding of the presence, magnitude, and diversity of contaminants in wet-weather discharges (e.g. Gasperi et al., 2014; Launay et al., 2016; Masoner et al., 2019; Mutzner et al., 2020; Rippy et al., 2017). Despite these efforts, the information gained with these monitoring campaigns is still limited, as most contain small, local datasets both in terms of sampled discharge events and spatial coverage. In this study, we use a data-driven statistical analysis of existing measurements collected at more than 60 wet-weather discharge sites to gain insight on the frequency of detection and relative abundance of trace contaminants. This information can be used to inform future monitoring efforts as utilities and regulators work towards building effective management strategies.

Published
2021

60. A comparative study of supported Ti[O.sub.2] as photocatalyst in water decontamination at solar pilot plant scale

Author

Kus, Mahmut, Gernjak, Wolfgang, Ibanez, Pilar Fernandez, Rodriguez, Sixto Malato, Galvez, Julian Blanco, and Icli, Siddik

Subjects
Titanium dioxide -- Usage, Solar collectors -- Analysis, Catalysis -- Analysis, Engineering and manufacturing industries, Environmental issues
Abstract

The degradation of gallic acid and imidacloprid with supported Millennium PC500 and Degussa P25 Ti[O.sub.2] is reported. Ti[O.sub.2] particles were immobilized using a titanium solsolution and direct deposition on glass supports. The film characterization was done by x-ray diffraction, scanning electron microscopy, and atomic force microscopy, and degradation of organic compounds was monitored by high-performance liquid chromatography, total organic carbon analyzer, and ion chromatography. The experiments were performed under sunlight in compound parabolic collector plants with flat supports inside the glass tubes. Photocatalytic activity of the films was compared and identified. Although sol-gel coatings had better mechanical properties, mineralization was observed to be approximately five times slower than paste-deposited films. Photoactivity of the films decreased with silver deposition due to the nature of the organic compounds. The rate constants were calculated to be between 2 x [10.sup.-1] and 6 x [10.sup.-2] mg [m.sup.2]/kJ for organic compounds, and 6 X [10.sup.-2] and 6 x [10.sup.-3] for total organic carbon. [DOI: 10.1115/1.2210494] Keywords: photocatalysis, supported catalyst, silver deposition, sol-gel film

Published
2006

61. Applied studies in solar photocatalytic detoxification: an overview

Author

Malato, Sixto, Blanco, Julian, Vidal, Alfonso, Alarcon, Diego, Maldonado, Manuel I., Caceres, Julia, and Gernjak, Wolfgang

Subjects
Refuse and refuse disposal, Rural -- Service development, Company service development, Earth sciences, Petroleum, energy and mining industries
Abstract

The technical feasibility and performance of photocatalytic degradation of four water-soluble pesticides (diuron, imidacloprid, formetanate and methomyl) have been studied at pilot scale in two well-defined systems which are of special interest because natural-solar UV light can be used for them: heterogeneous photocatalysis with titanium dioxide and homogeneous photocatalysis by photo-Fenton. The pilot plant is made up of compound parabolic collectors specially designed for solar photocatalytic applications. The initial concentration tested with imidacloprid, formetanate and methomyl was 50 and 30 mg/l with diuron, and the catalyst concentrations were 200 mg/l and 0.05 mM with Ti[O.sub.2] and iron, respectively. Total disappearance of the parent compounds, 90% mineralisation and toxicity reduction below the threshold (E[C.sub.50]) have been attained with all pesticides tested. All these results have contributed to an evaluation of photocatalytic treatment capacity and comments on the main parameters of Ti[O.sub.2] and Fe separation from the treated water.

Published
2003

66. Evaluation of innovative water treatments at molecular level based on high resolution mass spectrometry and advanced statistical analysis tools

Author

Gago Ferrero, Pablo, Alygizakis, Nikiforos A., Velo-Gala, I., Sbardella, Luca, Gernjak, Wolfgang, Petrović, Mira, and Ministerio de Economía y Competitividad (Espanya)

Subjects
Emerging contaminants in water, Sewage -- Purification, Contaminants emergents en l'aigua, Aigües residuals -- Depuració, Aigües residuals -- Anàlisi, Sewage -- Analysis
Abstract

Comunicació de congrés presentada a: 16 th International Conference on Environmental Science and Technology, celebrat a l'Illa de Rodes (Grecia), del 4 a 7 de setembre de 2019 This work aims at integrating the last advances in high resolution mass spectrometry (HRMS) and statistical analysis of data to develop and optimize a smart methodology (workflow) for the assessment of the performance of innovative water treatments using different technological approaches based on advanced oxidation processes with UV-254nm: (i) UV/K2S2O8, where oxidation takes place mainly following the initial formation of sulfate radicals, (ii) UV/KHSO5, where oxidation begins with the formation of both sulfate and hydroxyl radicals and (iii) UV/H2O2, when only the formation of hydroxyl radicals takes place initially. Experiments were carried out using secondary effluent from a local wastewater treatment plant. The developed workflow allows the evaluation of the treatments in terms of overall oxidation through the careful study of Van Krevelen diagrams, where all the masses of the HRMS chromatograms are considered. The potential formation of transformation products with sulfur due to the sulfate radicals was also evaluated using statistical tools based on the isotopic pattern and accurate mass. Finally, the behavior of a large number of micropollutants with a wide range of physicochemical properties was studied using suspect screening strategies This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement SMARTWORKFLOW (747698), the Spanish Ministry of Science and Innovation (grant number CTQ2015-69832-C4), and the Economy and Knowledge Department of the Catalan Government (Consolidated Research Group program: ICRATECH - 2017 SGR 1318 and ICRA-ENV - 2017 SGR 01124)

Published
2019

67. Consolidated vs new advanced treatment methods for the removal of contaminants of emerging concern from urban wastewater

Author

Rizzo, Luigi, primary, Malato, Sixto, additional, Antakyali, Demet, additional, Beretsou, Vasiliki G., additional, Đolić, Maja B., additional, Gernjak, Wolfgang, additional, Heath, Ester, additional, Ivancev-Tumbas, Ivana, additional, Karaolia, Popi, additional, Lado Ribeiro, Ana R., additional, Mascolo, Giuseppe, additional, McArdell, Christa S., additional, Schaar, Heidemarie, additional, Silva, Adrián M.T., additional, and Fatta-Kassinos, Despo, additional

Published
2019
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75. Influence of different RO membrane impairments on the rejection behaviour of virus surrogates - lab-scale study

Author

Pype, Marie-Laure, Patureau, Dominique, Wéry, Nathalie, Donose, Bogdan C., Gernjak, Wolfgang, Laboratoire de Biotechnologie de l'Environnement [Narbonne] (LBE), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de la Recherche Agronomique (INRA), Advanced Water Management Centre, University of Queensland [Brisbane], American Membrane Technology Association (AMTA). USA., Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), and ProdInra, Migration

Subjects
[SDV] Life Sciences [q-bio], [SDE] Environmental Sciences, [SDV]Life Sciences [q-bio], [SDE]Environmental Sciences
Published
2013

76. Occurrence of N-nitrosamines and their precursors in Spanish drinking water treatment plants and distribution systemsElectronic supplementary information (ESI) available. See DOI: 10.1039/c9ew00912d

Author

Farré, Maria José, Insa, Sara, Lamb, Aaron, Cojocariu, Cristian, and Gernjak, Wolfgang

Abstract

N-Nitrosamines are carcinogenic compounds that can be formed during disinfection processes as by-products in drinking and recycled water systems. Among them, N-nitrosodimethylamine (NDMA) is of particular interest, especially in systems employing chloramines, because its presence is regulated in various countries. Although there is a lot of emphasis on NDMA due to its toxicity, there may be other N-nitrosamines formed during disinfection processes that pose similar or higher toxicities and are currently scarcely studied. This work investigates the presence of NDMA and six additional N-nitrosamines in different drinking water treatment plants (DWTPs) and strategic sampling points from drinking water networks in Spain that employ monochloramines. The other N-nitrosamines investigated are N-nitrosodiethylamine (NDEA), N-nitrosomethylamine (NMEA), N-nitrosodibutylamine (NDBA), N-nitrosopiperidine (NPIP), N-nitrosodipropylamine (NDPA) and N-nitrosopyrrolidine (NPYR). Moreover, the fate of N-nitrosamine precursors was measured across different DWTPs. The actual concentration of NDMA in the final treated water and samples taken from the distribution system was never above 4.2 ± 0.2 ng L−1. NDEA and NDBA were also detected in almost all samples, however, their concentrations did not exceed 1.5 ng L−1in any case. The maximum concentration of NDMA formation potential following chloramination was 41.5 ± 4.3 ng L−1. The concentration of other N-nitrosamines originating during NDMA formation potential tests was lower than 3 ng L−1. Among the studied DWTPs, those that included ozone followed by granular activated carbon (GAC) in the treatment train removed NDMA formation potential best, showing that this can be an efficient strategy to control NDMA formation during drinking water production when chloramines are used in the distribution systems.

Published
2019
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80. Assessing Adsorbable Organic Halogen Formation and Precursor Removal during Drinking Water Production.

Author

Farré, Maria José, Lyon, Bonnie, de Vera, Glen A., Stalter, Daniel, and Gernjak, Wolfgang

Subjects
DRINKING water purification, CHLORIDE content of water, WATER treatment plants, DISINFECTION & disinfectants, TRIHALOMETHANE removal (Water purification)
Abstract

Adsorbable organic halogens (AOX) were measured at the outlet (AOXo) and after 24 h contact time with residual disinfectant (AOX24 h) for 10 samples obtained from 7 drinking water treatment plants (WTPs) that employ chlorine-based disinfectants. AOXo ranged from 0.75 to 7.60 µM (26.2-266.0 µgCl=L) and increased by up to 170% after 24 h contact time. The results were also compared with AOX formation potential (AOXFP) measured in the laboratory for the samples collected prior to disinfection at the same WTPs. In general, AOX24 h and AOXFP values varied by less than ±20%. A suite of disinfection byproducts (DBPs) were individually measured to elucidate the AOX composition. Trihalomethanes and haloacetic acids explained the largest fraction of AOX; however, the percentage of AOX not accounted for by measured DBPs varied greatly between samples (14.5-62.0%). Additionally, the fate of AOXFP was assessed across the seven WTPs. On average, coagulation removed 67 ± 7% of AOXFP across the WTPs, while dual media filtration did not substantially remove AOXFP. The effect of ozone on AOXFP varied between WTPs, while biological activated carbon filtration removed 33 ± 13% AOXFP. The ratio of known versus unknown AOXFP did not change across the WTPs. [ABSTRACT FROM AUTHOR]

Published
2016
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89. Preface

Author

Augugliaro, Vincenzo, primary, Gernjak, Wolfgang, additional, Malato, Sixto, additional, and Palmisano, Leonardo, additional

Published
2009
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93. Introduction by Guest Editors

Author

Malato Rodríguez, Sixto, primary, Gernjak, Wolfgang, additional, Pérez Peña, Jesús, additional, and Doña Rodríguez, José Miguel, additional

Published
2007
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100. Evaluating Microtox© as a tool for biodegradability assessment of partially treated solutions of pesticides using Fe3+ and TiO2 solar photo-assisted processes

Author

Lapertot, Milena, Ebrahimi, Sirous, Oller, Isabel, Maldonado, Manuel I., Gernjak, Wolfgang, Malato, Sixto, and Pulgarín, César

Subjects
PESTICIDE research, XENOBIOTICS, PHOTOCATALYSIS, PHOTODEGRADATION, BIODEGRADATION, TOXICITY testing, EDUCATION
Abstract

To shorten phototreatment time is of major concern for the cost and energy benefits of the xenobiotics degradation performed by photocatalytic processes. Using photo-Fenton and TiO2 phototreatments, partially photodegraded solutions of 6 separate pesticides (alachlor, atrazine, chlorfenvinphos, diuron, isoproturon and pentachlorophenol) were tested for biocompatibility, which was evaluated according to the Zahn–Wellens procedure. This study investigated if Microtox© could be considered as a suitable global indicator capable of giving information on the evolution of biocompatibility of the water solution contaminated with organic pollutants during the phototreatment in order to promote biotreatment. The obtained results demonstrated that biodegradability increased significantly after short photo-Fenton treatment times for alachlor, diuron and pentachlorophenol. Uncertain results were obtained with atrazine and isoproturon. Microtox© acute toxicity testing was shown to correctly represent dynamics and efficiency of phototreatment. [Copyright &y& Elsevier]

Published
2008
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