This article presents a natural coagulant obtained from Moringa oleifera seeds used to reduce water turbidity. The residue generated by an oil extraction plant from M. oleifera seeds is valuated as coagulant in an automatized water purification plant that needs power supply. The main objective of this study is to find the most suitable and sustainable power supply option with regards to a specific zone of Burkina Faso. This article discusses the possibility to deploy a sustainable system providing water purification and electricity to a village of Burkina Faso. Three scenarios are considered to power up the water purification plant (A: electricity grid, B: diesel generator and C: solar panels supported by second life EV batteries). The environmental impact of these three scenarios is done following the life cycle assessment (LCA) methodology based on energy and resources consumption during the material extraction, elements manufacturing, use and dismantle phases. The less pollutant option for this case in Burkina Faso is the “solar panels supported by second life EV batteries”. In comparison to the other scenarios, this system entails a significant reduction of the environmental impact, mainly in the categories of climate change and fossil depletion.
Treated wastewater (TWW) reuse for managed aquifer recharge (MAR) is becoming an important measure for integrated water management in areas with water scarcity. Among reuse applications, interest in aquifer recharge to control seawater intrusion in coastal aquifers is growing worldwide. At the Korba-Mida aquifer (Tunisia), local aquifer recharge with treated urban wastewater has taken place through three infiltration ponds since 2008. An ex post Cost–Benefit Analysis (CBA) is presented to assess the recharge impact at the groundwater level in a coastal aquifer after 3 years of recharge. A MODFLOW-based groundwater numerical model was developed to guide the impact assessment. The local model results showed that the recharged volume was slightly higher than extractions. The economic results indicated that the internal rate of returns accounted for 14.46%, while the discount rate of project investment was 4%. According to the sensitivity analysis, this project is feasible for the present wastewater treatment cost (0.1 TND per m3, Tunis Dinar) and up to 0.25 TND per m3. Possible effects on groundwater quality as an added influential final externality cost were not considered.
Understanding organic fouling on ultrafiltration (UF) membranes during water filtration and cleaning episodes has become one of the major factors driving UF technology forward. The aim of this study was to quantify and characterise the organic foulants on an UF membrane at a full-scale drinking water treatment plant when it is fed with surface water and groundwater with different dissolved organic carbon (DOC) contents. DOC characterisation was performed by high-performance size-exclusion chromatography and fluorescence excitation–emission matrix (FEEM). The masses of DOC (and its fractions) retained by the membrane over a whole filtration period (and detached during cleaning episodes) were calculated through mass balances. Under river water feeding conditions, DOC was retained by 22%, being biopolymers the most retained DOC fraction (59%), followed by humic substances (17%) and other minor organic fractions. Routine backwashing resulted in the detachment of only 8% of the total mass of DOC retained, with biopolymers as the most detached fraction (27%). Within biopolymers, proteins appeared to contribute more to hydraulically irreversible fouling than polysaccharides. Under groundwater feeding conditions, no apparent retention of DOC was observed. FEEM analyses showed neither significant removal of fluorescent components during filtration nor detachment from the UF membrane during routine backwashing.
Gibert, O.; Lefevre, B.; Ferrer, O.; Prats, G.; Bernat, X.; Paraira, M. Desalination and water treatment Vol. 57, num. 54, p. 26313-26326 DOI: 10.1080/19443994.2016.1172987 Data de publicació: 2016-11-01 Article en revista
The primary problem for the application of microfiltration (MF) and ultrafiltration (UF) membrane technology is membrane fouling. Such is the case that understanding membrane fouling has become one of the major factors driving MF and UF membrane technology for- ward. Nevertheless, identifying the constituents that most contribute to membrane fouling 20 and quantifying how they are detached when backwashing (BW) and cleaning-in-place (CIP) are applied still remains a challenging task. The aim of the present study was to quan- tify membrane fouling development during filtration and membrane fouling detachment during BW and CIP in terms of membrane permeability changes and masses of inorganic and organic constituents accumulated on the membrane. The study was conducted using 25 bench-scale MF and UF modules fed with coagulated and settled water coming from a drinking water treatment plant and operated under dead-end and cross-flow operation modes. The experiments consisted inconsecutive permeation (20 min) alternated with BW with permeate water (1.0 min) (periodically chemically assisted with NaClO and NaOH) and followed by a two-stage CIP consisting first in an oxidising and basic step (NaClO and 30 NaOH) and second in an acidic step (citric acid). Feed, permeate, retentate (when present) and cleaning discharge streams were monitored for turbidity, total and dissolved organic carbon (TOC and DOC, respectively), UV 254 and inorganic ions (Al, Fe, P). DOC was frac- tionated by high-performance size exclusion chromatography to gain insight into the beha- viour of the different organic fractions. Results showed that both MF and UF membranes 35 successfully removed turbidity, Al and Fe, whereas UV 254 was moderately removed and TOC and DOC poorly removed, with removal percentages higher for UF than for MF. With regard to the organic fractions, the largest molecular weight compounds were moderately removed while the smallest organic fractions seemed to totally permeate through both membranes. The results also showed that foulants were poorly washed out from the
Ferrer, O.; Lefevre, B.; Prats, G.; Bernat, X.; Gibert, O.; Paraira, M. Desalination and water treatment Vol. 57, num. 19, p. 8593-8607 DOI: 10.1080/19443994.2015.1022807 Data de publicació: 2016-05-20 Article en revista
Membrane fouling is an inherent phenomenon in ultrafiltration (UF) membrane processes, making it necessary to periodically perform backwashes (BW) and chemical cleanings in place (CIP) to restore the initial permeability of the membrane. The objective of this study was (1) to explore systematically the effect of distinct BW-related variables (BW transmembrane pressure, duration, frequency and composition) on the reversibility of UF membrane fouling and on the permeate quality (in terms of total organic carbon, turbidity and UV absorbance) over successive filtration/BW cycles; and (2) to identify which organic fractions were most removed by the membrane and, of these, which were most detached after BW, alkaline and oxidant CIP and acid CIP episodes. For this purpose, a bench-scale outside-in hollow fibre module operated under dead-end filtration mode at constant transmembrane pressure and treating settled water from a drinking water treatment plant was employed. Dissolved organic carbon fractionation was performed by high-performance size-exclusion chromatography. Results showed that, in general, the more intensive the BW was (in terms of high transmembrane pressure, shortened frequency and prolonged duration) the more effective it was in removing fouling from the membrane. Concerning the composition of the water used for the BW, the addition of NaClO led to maximum fouling reversibility, closely followed by the combination of NaOH+NaClO, while citric acid and NaOH contributed little compared to water alone. However, results also showed that irreversible fouling was never completely avoided whatever the BW regime applied, leading to a gradual increase in the total resistance over time. Larger differences in the behaviour of the different organic fractions were observed. UF membrane preferentially retained the heaviest fraction of biopolymers (BP), while the intermediate fraction of humic substances (HS) was removed at a lower percentage and the lighter fractions seemed to entirely pass through the UF membrane. The successive application of BW and CIPs resulted in the detachment from the membrane of a significant percentage of the retained BP, whereas only a modest percentage of the retained HS.
Waste stabilization ponds (WSP), in spite of being a suitable technology for wastewater treatment, present low phosphorus removal. This study aimed at evaluating the net increase on phosphorus removal efficiency in microcosm WSP in which sludge was conditioned with an adsorbent (industrial by-product) having a high phosphorus retention capacity. In order to determine the best candidate to condition the sludge, four different industrial by-products (granular bentonite; fly ashes from a municipal solid waste incineration plant; and two types of fly ashes from power plants) were tested for their phosphorus adsorption capacity. Experimental results were fitted to Langmuir and Freundlich models. All adsorbents showed a high phosphorus adsorption capacity. Maximum phosphorous adsorption capacity estimated from Langmuir equations ranged between 34.7 and 74.0 mgP/g adsorbent, being fly ashes from a power plant and granular bentonite the adsorbents with the highest and lowest adsorption capacity, respectively. Microcosms WSP were set up and the sludge conditioned with fly ashes from a municipal solid waste incineration plant. Results showed that phosphorus removal efficiency increased up to 90% by adding 5% of adsorbent (in terms of weight of adsorbent to weight of sludge). Main conclusion is that of industrial by-products may be a low-cost solution for enhancing phosphorus removal in WSP.
This is an Accepted Manuscript of an article published by Taylor & Francis Group in Desalination and Water Treatment on 2016, available online at: http://www.tandfonline.com/10.1080/19443994.2014.977957
The generation of high-coloured wastewater is one of the main environmental problems of the textile industry. Reactive dyes are widely used in the dyeing of cellulosic fibres. However, they have low exhaustion degree (70–90%). The degradation of residual dyes by aerobic biological treatment is very poor, being necessary the application of specific treatments. In this work, three different methods for the removal of reactive dyes were compared: electrochemical treatment, coagulation with Moringa oleifera waste and enzymatic treatment with laccase. Two azo bifunctional dyes with different reactive groups were selected: C.I. Reactive Black 5 (vinyl sulphone) and C.I. Reactive Red 231 (chlorotriazine). The influence of pH (5 and 9) and dye hydrolysis on the decolourisation yield was studied. The electrochemical treatment was the most efficient, with 95–100% colour removal yield. The coagulation with M. oleifera waste also achieved high colour removal efficiency (91–94%). Both methods showed an independent behaviour with respect to pH or dye hydrolysis. The enzymatic treatment should be performed at pH 5. This method was suitable to remove the chlorotriazine dye (92–93% efficiency), whereas the vinyl sulphone one showed a marked dependence on dye hydrolysis: moderately efficient for the hydrolysed dye and highly efficient without hydrolysis. The activity of laccase was not modified by the usual salinity of the reactive dyeing effluent (20 g/L NaCl). Nevertheless, the effluent salinity enhanced the electrochemical and M. oleifera treatment yield.
An innovative proposal of tangento-axial filtration based on the concept of macromembrane (large size) is presented in the context of micro- and ultrafiltration ceramic membranes. The macromembrane is made of Al2O3–TiO2 by slip casting. It includes an internal system for rotating the fluid trough a propeller which enhances the tangento-axial filtration. This filtration yields better than the cross-flow filtration in conventional extruded ceramic tubes of small diameter. The reasons are, first, its larger sizes relative to the extruded tubular filters, and second, that it can work at higher pressures, resulting in better operational performance. Furthermore, costs of industrial-scale production could be lower. In this study, the conceptual basis, pilot plant, first experimental results, and proposals for improvement of the system to continue the project are presented.
Chicken feathers (CFs), waste from the poultry industry, were tested as biosorbent for colour removal of synthetic coloured water. Biosorption kinetics and isotherms were determined to provide an explanation to the physicochemical behaviour of the biosorption process of C.I. Acid Blue 80 dye on CFs. Up to 80% of the dye was biosorbed at 50°C demonstrating the biosorbent potential of the waste for the removal of organic dyes. Moreover, two mathematical approaches have been used to estimate the thermodynamic parameters such as the enthalpy, the entropy and the affinity of sorption. The first approach uses the Langmuir equation (affinity of sorption of 27,514 J/mol at 50°C) whereas the second approach calculates the affinity directly using the chemical potentials. In both cases, the affinity of the system is positive indicating that the biosorption process occurs spontaneously. In addition, the infrared spectroscopy and scanning electron microscopy results shown that the chemical structure and the morphology of the fibres were not significantly affected by the biosorption step
In this work, the feasibility of polyvinylidene difluoride ultrafiltration membranes to treat textile wastewater was studied. The C.I. Disperse Orange 30 and C.I. Disperse Rubine 73 were selected as pollutant for the membrane filtration study. The results showed about 90 and 96% of COD decrease and dye removal, respectively. In addition, very low fouling was observed which demonstrated the feasibility of applying this type of membranes to treat textile wastewater. Finally, after the membrane treatment, 100% of the obtained permeate was reused. Fabrics dyed with the reused water were evaluated with respect to references carried out with softened tap water. No significant colour differences were observed between reference fabrics and the fabrics dyed with the permeate
Wetlands, as active riparian areas in denitrification processes, are largely dependent on the environment. The main objective of this paper is to evaluate changes in the denitrification potential of wetland soils at laboratory scale promoted by climatic and seasonal influences. Several batch denitrification tests were performed with fresh wetland soil (peat) from Brynemade (Denmark) under: three different temperatures (20, 10, and 5 degrees C), drought period, and freeze-thaw event. Results show that nitrate was eliminated in all the experiments in percentages over 90%. However, not all the nitrate removed was reduced to nitrogen gas via the denitrification process; dissimilatory nitrate reduction to ammonium (DNRA) was also present. In fact, the percentage of total nitrogen eliminated at the end of the tests was: 79.7% at 20 degrees C, 84.1% at 10 degrees C, 82.9% at 5 degrees C, 41.0% in the dried soil, and 57.0% in the frozen soil. Thus, it can be concluded that the drying and freezing of the soil favor the DNRA process. Furthermore, in these conditions, nitrite increased sharply and was also accumulated possibly, as a DNRA or denitrification intermediate. Nitrate removal was fitted to a zero-order model, and an increase of the denitrification rates with the temperature was observed (3.8mg; [GRAPHICS]; L(-1)d(-1) at 20 degrees C, 3.0mg; [GRAPHICS]; L(-1)d(-1) at 10 degrees C, and 2.9mg; [GRAPHICS]; L(-1)d(-1) at 5 degrees C). These overall rates were modeled as a function of temperature by the Arrhenius equation and activation energy of 12.88kJ mol(-1) was determined. The fact that the activation energy is low in this work (unstirred batches) compared to previous publications (stirred batches) could be the result of a strong restriction on the nitrate mass transfer in the soil vs. reaction kinetics, which masks kinetic regulating factors of the denitrification rate. Thus, the variation of the denitrification rate with temperature is possibly the result of a combination of changes in mass transfer (diffusive transport) and kinetic constant variation, successfully modeled by the Arrhenius equation.
Messele, S. A.; Bengoa, C.; Stüber, F.; Fortuny, A.; Fabregat, A.; Font, J. Desalination and water treatment Vol. 57, num. 11, p. 5155-5164 DOI: 10.1080/19443994.2014.1002011 Data de publicació: 2015-01-19 Article en revista
The main objective of the work is to prepare catalysts based on nanoscale zero-valent iron supported on activated carbon (nZVI/AC) and to test their activity for catalytic wet peroxide oxidation of phenol. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), ICP, and N2 adsorption–desorption, and their performance was evaluated in terms of phenol and TOC removal. The effect of the initial phenol concentration and initial pH on the oxidation process was investigated. Possible leaching of iron from the catalyst into the aqueous solution was also examined. The experimental results indicate that the catalytic activity toward phenol degradation was found to be enhanced by nZVI/AC catalysts compared to that of Fe/AC. In the range 150–1,000 mg/L, phenol conversion above 90% can be reached using these catalysts after only 15 min of the reaction, and using the stoichiometric hydrogen peroxide for complete mineralization. The leaching observed is less than 4% of the total initial iron in the catalyst even after 120 min of the reaction. It was also observed that the stability or reutilization of the catalyst was fairly good.
Licon , E.; Reig, M.; Villanova, P.; Valderrama, C.; Gibert, O.; Cortina, J. Desalination and water treatment Vol. 56, num. 13, p. 3607-3616 DOI: 10.1080/19443994.2014.974216 Data de publicació: 2015-01-01 Article en revista
This study is on the reuse of the residue generated by a Moringa oleifera oil extraction plant. The residual oil cake produced during the process of oil extraction retains the positively charged protein of the M. oleifera seed, which is the active component in the process of attracting and capturing suspended particles in waters. Such coagulant flocculant properties give rise to the elimination of turbidity in the process of water purification. In the cases studied, it has been demonstrated that the same amount (100 mg/L) of Aluminum sulfate coagulant and M. oleifera coagulant is required to reduce water turbidity to levels within the International guidelines (<5 NTU).
A Life Cycle Analysis (LCA) is also presented in which the coagulant obtained from M. oleifera is compared with conventional chemical coagulants. The energy consumption per kg of aluminum sulfate (Al2(SO4)3 ) produced is almost 40% greater than M. oleifera -based coagulant. Furthermore, carbon dioxide (CO2) emissions associated with alum are 80% higher than those of the M. oleifera -based coagulant. In addition to turbidity removal, with lower energy consumption and reduced CO2 emissions, the coagulant derived from the residual oil cake does not provoke any alterations to water pH or conductivity and, therefore, does not require any additional readjustment of these parameters.
Marianna Garfi'; Pedescoll, A.; Carretero, J.; Puigagut, J.; Garcia, J. Desalination and water treatment Vol. 52, num. 31-33, p. 5848-5855 DOI: 10.1080/19443994.2013.811443 Data de publicació: 2014-09-19 Article en revista
This study aimed at determining the reliability and feasibility of constructed wetlands (CWs) performance evaluation by online monitoring. Redox potential (E-H), turbidity and ammonium (NH4) were continuously monitored for one year by means of online sensors in a pilot plant based on horizontal sub-surface flow constructed wetlands (HSSF CWs). Results were compared with conventional laboratory analyses. Online measures and laboratory analyses showed good agreement for NH4 (r = 0.84, p < 0.01). A significant correlation was also found for: online turbidity vs. Total suspended solids (TSS) (r = 0.85, p < 0.01); online turbidity vs. Biochemical oxygen demand (BOD) (r = 0.88; p < 0.01) and E-H vs. BOD (r = -0.62; p < 0.01). Results suggested that in full-scale CWs, continuous monitoring of turbidity, E-H and NH4 would help to both daily monitoring and improvement of CWs performance. A general overview about economic aspects suggested that, continuous monitoring of wastewater quality could be technically feasible and cheaper than traditional chemical-based monitoring.
Reig, M.; Pagès, N.; Licon, E.; Valderrama, C.; Gibert, O.; Yaroshchuk, A.; Cortina, J. Desalination and water treatment p. 1-11 DOI: 10.1080/19443994.2014.974215 Data de publicació: 2014-04-27 Article en revista
Nanofiltration (NF) membranes can be used in different configurations. The aim of this work was to determine the reliability of the data obtained using flat-sheet (FS) laboratoryscale configuration when NF membranes are implemented at industrial scale level using spiral wound (SW) configuration. Ion rejections in salt mixtures with the two configurations types were analysed, modelled, evaluated and compared. In both cases of the study, the
operation was carried out in cross-flow mode and with recirculation of permeate and concentrate streams into the feed tank. Different feed synthetic salt solutions were used based on a dominant and a trace salt. In both cases, the operating temperature was kept constant (21.5 ± 2.5°C), and the trans-membrane pressure range varied from the osmotic pressure to 20 bar. The same NF membrane was used for both configurations: NF270 (Dow Chemical).
The solution–diffusion–electromigration–film model was employed to describe the experimental results. Comparing both membrane configurations, the trans-membrane flux obtained with the FS configuration was higher than that observed with the SW configuration under the same operating conditions. In general, it is proved that ion rejection curves for both membrane configurations were fairly similar. Moreover, the membrane permeances
with respect to each ion in both configurations were quantitatively similar.
Gaaloul, N.; Candela, L.; Chebil, A.; Soussi, A.; Tamoh, K. Desalination and water treatment Vol. 52, num. 10-12, p. 1997-2008 DOI: 10.1080/19443994.2013.821026 Data de publicació: 2014 Article en revista
During the last few decades, the Grombalia shallow, an unconfined aquifer, had been under stress by groundwater pumping due to the increasing population and development of agricultural activity. Recently, the aquifer has displayed an important decline in the water level of boreholes and wells, and considerable deterioration of groundwater quality due to saltwater intrusion. A groundwater numerical model for the Grombalia aquifer has been developed based on the Visual Modflow 3.1 code to simulate the groundwater changes under steady state regime and transient conditions. The results of the model show reasonable agreement between observed and estimated groundwater levels in the observation wells. Sebkaht Soliman wetland aquifer connection has been identified. This paper presents the effect of different groundwater management scenarios and pumping discharge on groundwater resources in the Grombalia aquifer (Cap-Bon peninsula, Tunisia).
In this work, the feasibility of reusing water and salt from reactive dyebaths after electrochemical
decolourization was evaluated. Dyeing series of ten reuses with three reactive dyes
(Navy Blue Procion H-EXL, Crimson Procion H-EXL and Yellow Procion H-EXL) were
carried out (individually and in a trichromie) and color differences and total organic carbon
values were measured to study how the successive reuses affect the quality dyeing. The first
reuse produced dyeings with low colour differences with respect to a standard dyeing. In
the subsequent reuses, colour differences increased until they reached a constant value at the
4th or 5th reuse, following a similar behavior to the organic matter content. At this point, it
is determined the percentage of dye increase that allows for continuous dyeing of acceptable
quality for the textile industry. To obtain dyeings with acceptable color differences (DE
(2:1) 6 1) independent of the number of consecutive reuses, a 30% increase in blue dyestuff
and 10% for red dyestuff must be added, whereas in the case of yellow dyeing, it was not
necessary to increase the dye amount after subsequent reuses. In each dyeing, this process
allowed savings of 70% of water and an average of 60% for salt.
Santasmasas Rubiralta, C.; Rovira, M.; Clarens Blanco, F.; Valderrama, C. Desalination and water treatment Vol. 51, num. 10-12, p. 2423-2430 DOI: 10.1080/19443994.2012.747476 Data de publicació: 2013-02 Article en revista
The design and implementation of membrane bioreactor (MBR) pilot plant was performed in order to treat municipal wastewater derived from the Suria municipality (Catalonia, Spain) wastewater treatment plant. Two submerged membrane configurations (flat sheet and hollow fibre) in MBR pilot plant were used for this purpose. The influent and effluents were monitored and controlled in order to ensure the achievements of the highest quality determined by Spanish legislation for water reuse. The Remosa company interest was focused in pilot plants applications for the small urban areas. Taking into account that the level of control and maintenance of this small plant can be lower than recommended, the start-up was performed under less favourable conditions without any sludge seed. After 8-months of continuous operation, the physico-chemical and microbial parameters of both MBR configurations achieved the water quality specifications defined for urban service, agricultural and recreational uses...
Valdés-Abellán, J.; Candela, L.; Jiménez- Martínez, J.; Saval, J. Desalination and water treatment Vol. 51, num. 10-12, p. 2431-2444 DOI: 10.1080/19443994.2012.747506 Data de publicació: 2013 Article en revista
Desalinated brackish groundwater is becoming a new source of water supply to comply with growing water demands, especially in (semi-) arid countries. Recent publications show that some chemical compounds may persist in an unaltered form after the desalination processes and that there is an associated risk of mixing waters with different salinity for irrigation. At the university of Alicante campus (Spain), a mix of desalinated brackish groundwater and water from the existing aquifer is currently applied for landscape irrigation. The presence of 209 emerging compounds, surfactants, priority substances according to the 2008/105/EC Directive, 11 heavy metals and microbiological organisms in blended water and aquifer samples was investigated. Thirty-five compounds were detected (pesticides, pharmaceuticals and surfactants) among them two priority substances a-endosulfan and Ni were found above the permitted maximum concentration. Blended water used for landscape irrigation during the summer period is supersaturated with respect to carbonates, which may ultimately lead to mineral precipitation in the soil-aquifer media and changes in hydraulic parameters.
Ferrer-Roca, O.; Serrallach, X.; Horvath, F.; Mesa, J.; Gibert, O.; Bernat, X. Desalination and water treatment Vol. 51, num. 7, p. 1831-1837 DOI: 10.1080/19443994.2012.714637 Data de publicació: 2013 Article en revista
The feasibility of raw river direct ultrafiltration, as an alternative to conventional drinking water treatment plant pre-treatment, was investigated at prototype scale (May–October 2011). A highly variable and challenging water resource was selected, in order to assess different scenarios, covering a broad range of conditions. The prototype was able to deal with conditions ranging from 20 to >800NTU successfully, without any chemical pre-treatment and consuming low amount of chemical reagents for cleaning purposes. The membranes’
performance proved to work better in terms of water production yield and resistance build up stability at medium and high turbidity episodes than at lower ones, probably due to a cake layer formation which prevented small binding organic species and particles reaching the membrane. Permeate quality, both in physico-chemical and microbiological terms, was independent of the feed water characteristics.
Ribera, G.; Llenas, L.; Martinez, X.; Rovira, M.; De Pablo, J. Desalination and water treatment Vol. 51, num. 1-3, p. 458-468 DOI: 10.1080/19443994.2012.714527 Data de publicació: 2012-08-10 Article en revista
Nanofiltration (NF) membranes have been largely developed and commercialised over the past decade and are currently one of the most promising technologies for the separation of neutral and charged solutes in aqueous solutions. Sometimes NF is defined as a process between ultrafiltration and reverse osmosis; however, the separation mechanisms of this kind of membranes are not clear enough, and even today there are some questions remaining about how NF membranes work. Nowadays, there are many different types of NF membranes commercially available, so the first step before developing a new NF treatment plant is to know which one is going to be the most suitable membrane. There are two main configurations in which NF can be used: flat sheet and spiral wound module. The cross-flow module using flat sheet membranes is the simplest option to test an NF membrane but at the industrial scale, NF is basically used in the spiral wound configuration. Currently, there are no studies available regarding the difference of using both configurations. The objective of this work is to do an experimental study regarding the performance of two different NF membranes, NF270 (Dow Chemical) and ESNA 1-LF2 (Hydranautics), in two different scales, laboratory and pilot plant, using the most typical configurations in each case: flat sheet and spiral wound respectively. Using the same feed water, the operating conditions and the rejections of the membranes in both configurations will be studied in order to check if both operating scales can be comparable.
Electrochemical techniques offer many advantages for the treatment of industrial effluents. These processes are clean, operate at room temperature, and in most cases, do not need the addition of reagents (as in the case of reactive dyeing effluents). In particular, the electrochemical treatment of textile effluents is an efficient method to remove colour. In this work, diverse synthetic effluents containing reactive dyes were treated in an electrochemical cell with Ti/PtO x electrodes. The efficiency of the process to remove colour and the use of an additional UV irradiation were evaluated. Once the conditions were established in synthetic effluents, they were applied on two types of exhausted reactive dye baths collected from a cotton mill. Instead of the effluent discharge, another possibility is to reuse the decoloured effluents for a new dyeing process. In this sense, diverse experiments were carried out and conditions for the effluents reuse were established. The reuse of dyeing effluents implies an important reduction of the salt and water consumption as well as a reduction of the salinity of the discharged effluents.
Ribera, G.; Llenas, L.; Rovira, M.; De Pablo, J.; Martinez, X. Desalination and water treatment Vol. 51, num. 1-3, p. 448-457 DOI: 10.1080/19443994.2012.714528 Data de publicació: 2012-08-06 Article en revista
A wide range of commercial membranes were tested and compared at laboratory scale in order to select the most appropriate for improving the final water quality of a real drinking water treatment plant (DWTP). Most of the membranes tested showed a reduction of trihalomethanes formation potential (THMFP) higher than 90%. In this work, several NF membranes were tested at laboratory scale in order to evaluate the most suitable NF membrane to reduce THMFP. NF270 (Dow Chemical) and ESNA1LF2 (Hydranautics) were finally selected based on their permeability and inorganic salt rejection. These two membranes were tested in parallel in a pilot-scale plant. The effectiveness in THMPF removal was evident for all membranes tested. The comparison of both membranes was carried out simultaneously in a pilot plant installed in the DWTP of Manresa. In the spiral wound configuration, both membranes also showed effective separation of trihalomethanes (THM) precursors, reducing THMFP in treated water at values of approximately 90%, depending on the season.
Visa, T.; Sanchez, M.; Lopez-Grimau, V.; Navarro, R.; Reche, S.; Gutierrez-Bouzán, C. Desalination and water treatment Vol. 45, num. 1-3, p. 91-99 DOI: 10.1080/19443994.2012.692014 Data de publicació: 2012-05-16 Article en revista
Llenas, L.; Yaroshchuk, A.; Rovira, M.; Martinez, X.; De Pablo, J. Desalination and water treatment Vol. 36, num. 1-3, p. 310-318 DOI: 10.5004/dwt.2011.2767 Data de publicació: 2011-12 Article en revista
The aim of this experimental work was to evaluate the carbonaceous constituents in textile wastewater, and the infl uence of slowly biodegradable products, also to compare two processes: Membrane bioreactor (MBR) and activated sludge (AS) for treating textile wastewater. The MBR pilot plant includes an aerobic reactor of 50 l, and membranes of micro and ultra fi ltration, the AS pilot plant has an aerobic reactor of 4 l. The processes were run 3 times over 244 d, with the same relative F/M and SRT. Respirometry was carried out to fi nd the carbonaceous constituents in the wastewater, and also the Ultimate BOD, the mixed liquor suspended solids (MLSS) to evaluate the sludge, and different analysis: chemical oxygen demand and color removal, in order to evaluate process performance. The results show that the range of reduction of COD emissions using the MBR was 89–92%, and using AS was 54–70%, the color removal using MBR was 70% with MF membranes, and 72–73% with UF membranes, and 28% using AS. These results demonstrated that the textile wastewater could be treated by biological treatment but with high SRT, and also that the MBR is more effi cient and stable that a conventional activated sludge process for treating textile wastewater