Efficient fitting of nanofiltration model parameters for a specified groundwater type by selecting suitable characterization data-sets

Nanofiltration (NF) models can be useful to perform optimal designs of membrane systems and to estimate membrane performance for waters. There is a special interest in obtaining NF models with parameters based on measurable properties of the membrane and independent from the feed and operating conditions. However, many times, from a practical point of view, NF parameters can be directly fitted from experiments performed with salts in a range of compositions. The aim of this study is to select the better combination of experiments to yield a suitable fitting for the NF model Donnan steric-partitioning pore model with dielectric exclusion (DSPM-DE). In our case, the best fitting for a specific group of waters is searched (groundwater belonging to a Mediterranean region with moderate salinity). The first part of the work is devoted to study which combinations of salts and concentrations lead to higher information. Using known values of NF parameters, permselective results were computationally generated using the NF model for a huge number of different combinations of compositions and random parameter sets. Performance factors for permeate flux and rejection based on the comparison between the characterization groups and a control group were defined. The second part of the work focused on the experimental validation of the selection procedure. The results showed that there are characterization sets (composition and operating conditions) that yield higher fitting performance. These combinations of experiments should be the preferred ones, when direct fitting from experiments is going to be performed.This work was supported by the Ministry for Economy and Competitiveness [CTM2010-20248 (Project OPTIMEM)], [BES-2011-049230].Fernández Fernández, I.; Gozálvez Zafrilla, JM.; Santafé Moros, MA. (2014). Efficient fitting of nanofiltration model parameters for a specified groundwater type by selecting suitable characterization data-sets. Desalination and Water Treatment. 1-10. doi:10.1080/19443994.2014.946714S110Bowen, W. R., & Mukhtar, H. (1996). Characterisation and prediction of separation performance of nanofiltration membranes. Journal of Membrane Science, 112(2), 263-274. doi:10.1016/0376-7388(95)00302-9Bowen, W. R., & Welfoot, J. S. (2002). Modelling the performance of membrane nanofiltration—critical assessment and model development. Chemical Engineering Science, 57(7), 1121-1137. doi:10.1016/s0009-2509(01)00413-4Otero, J. A., Mazarrasa, O., Villasante, J., Silva, V., Prádanos, P., Calvo, J. I., & Hernández, A. (2008). Three independent ways to obtain information on pore size distributions of nanofiltration membranes. Journal of Membrane Science, 309(1-2), 17-27. doi:10.1016/j.memsci.2007.09.065Kotrappanavar, N. S., Hussain, A. A., Abashar, M. E. E., Al-Mutaz, I. S., Aminabhavi, T. M., & Nadagouda, M. N. (2011). Prediction of physical properties of nanofiltration membranes for neutral and charged solutes. Desalination, 280(1-3), 174-182. doi:10.1016/j.desal.2011.07.007Straatsma, J., Bargeman, G., van der Horst, H. C., & Wesselingh, J. A. (2002). Can nanofiltration be fully predicted by a model? Journal of Membrane Science, 198(2), 273-284. doi:10.1016/s0376-7388(01)00669-xWilks, S. S. (1941). Determination of Sample Sizes for Setting Tolerance Limits. The Annals of Mathematical Statistics, 12(1), 91-96. doi:10.1214/aoms/1177731788Luo, J., & Wan, Y. (2011). Effect of highly concentrated salt on retention of organic solutes by nanofiltration polymeric membranes. Journal of Membrane Science, 372(1-2), 145-153. doi:10.1016/j.memsci.2011.01.066Bargeman, G., Vollenbroek, J. M., Straatsma, J., Schroën, C. G. P. H., & Boom, R. M. (2005). Nanofiltration of multi-component feeds. Interactions between neutral and charged components and their effect on retention. Journal of Membrane Science, 247(1-2), 11-20. doi:10.1016/j.memsci.2004.05.022Cavaco Morão, A. I., Szymczyk, A., Fievet, P., & Brites Alves, A. M. (2008). Modelling the separation by nanofiltration of a multi-ionic solution relevant to an industrial process. Journal of Membrane Science, 322(2), 320-330. doi:10.1016/j.memsci.2008.06.003Afonso, M. (2001). Streaming potential measurements to assess the variation of nanofiltration membranes surface charge with the concentration of salt solutions. Separation and Purification Technology, 22-23(1-2), 529-541. doi:10.1016/s1383-5866(00)00135-0Hussain, A. A., Nataraj, S. K., Abashar, M. E. E., Al-Mutaz, I. S., & Aminabhavi, T. M. (2008). Prediction of physical properties of nanofiltration membranes using experiment and theoretical models☆. Journal of Membrane Science, 310(1-2), 321-336. doi:10.1016/j.memsci.2007.11.005Nguyen, N. C., Chen, S.-S., Hsu, H.-T., & Li, C.-W. (2013). Separation of three divalent cations (Cu2+, Co2+ and Ni2+) by NF membranes from pHs3 to 5. Desalination, 328, 51-57. doi:10.1016/j.desal.2013.08.011Wang, D.-X., Wang, X.-L., Tomi, Y., Ando, M., & Shintani, T. (2006). Modeling the separation performance of nanofiltration membranes for the mixed salts solution. Journal of Membrane Science, 280(1-2), 734-743. doi:10.1016/j.memsci.2006.02.032Nanda, D., Tung, K.-L., Hsiung, C.-C., Chuang, C.-J., Ruaan, R.-C., Chiang, Y.-C., … Wu, T.-H. (2008). Effect of solution chemistry on water softening using charged nanofiltration membranes. Desalination, 234(1-3), 344-353. doi:10.1016/j.desal.2007.09.103Lin, Y.-L., Chiang, P.-C., & Chang, E.-E. (2007). Removal of small trihalomethane precursors from aqueous solution by nanofiltration. Journal of Hazardous Materials, 146(1-2), 20-29. doi:10.1016/j.jhazmat.2006.11.05

Experimental simulation of continuous nanofiltration processes by means of a single module in batch mode

[EN] This work proposes a method of simulating the performance of continuous nanofiltration processes by means of experimental runs performed on a laboratory set-up equipped with a spiral-wound module working in batch recirculation mode. It describes how to implement the proper changes in feed concentration and operating conditions in a batch recirculated system in order to obtain similar conditions to those of a continuous one. The analogy between the concentration process in the continuous and in the batch recirculation system is discussed and the difference in ion concentration of the cumulative permeate between the two systems is estimated numerically. The procedure was applied in a case study to estimate the performance of a continuous process intended to remove nitrate from brackish water using a high rejection nanofiltration membrane (DowFilmtec NF90). The sequence of concentration steps performed in the batch-recirculated set-up yielded an estimation of the ion concentration profiles throughout the continuous system. A mathematical analysis of the results showed that the nitrate concentration in the permeate experimentally obtained in the batch system is 4.5% higher than that expected in the continuous system. The experimental method described here can be used to design membrane system applications for which the target ions are not accurately predicted by models or are not included in commercial software. (C) 2017 Published by Elsevier B.V.This work was supported by the Spanish Ministry for Economy and Competitiveness [Project OPTIMEM CTM2010-20248].Santafé Moros, MA.; Gozálvez-Zafrilla, JM.; Lora-García, J. (2017). Experimental simulation of continuous nanofiltration processes by means of a single module in batch mode. Separation and Purification Technology. 187:233-243. https://doi.org/10.1016/j.seppur.2017.06.05923324318

Comparison of Artificial Intelligence Control Strategies for a Peristaltically Pumped Low-Pressure Driven Membrane Process

Peristaltic pumping is used in membrane applications where high and sterile sealing is required. However, control is difficult due to the pulsating pump characteristics and the time-varying properties of the system. In this work, three artificial intelligence control strategies (artificial neural networks (ANN), fuzzy logic expert systems, and fuzzy-integrated local models) were used to regulate transmembrane pressure and crossflow velocity in a microfiltration system under high fouling conditions. A pilot plant was used to obtain the necessary data to identify the AI models and to test the controllers. Humic acid was employed as a foulant, and cleaning-in-place with NaOH was used to restore the membrane state. Several starting operating points were studied and setpoint changes were performed to study the plant dynamics under different control strategies. The results showed that the control approaches were able to control the membrane system, but significant differences in the dynamics were observed. The ANN control was able to achieve the specifications but showed poor dynamics. Expert control was fast but showed problems in different working areas. Local models required less data than ANN, achieving high accuracy and robustness. Therefore, the technique to be used will depend on the available information and the application dynamics requirements.This research received no external funding.Peer ReviewedPostprint (published version

Implementation of membrane models on a CAPE-OPEN tool to simulate a process including RO membranes

Process simulators are a useful tool for evaluating different configurations of chemical processes and developing new ones. Although these programs include many standard units like reactor or distillation towers, membrane units are not usually included. In this paper, it is shown the possibility to implement a reverse osmosis (RO) membrane unit in the free process simulator COCO, using input membrane parameters. The RO modeling is based on the coupling of the solution diffusion model with a model for concentration polarization. The model was implemented as a Matlab CAPE-OPEN unit operation. In order to show the functionality of the developed application, a rinsing process adapted from literature was implemented to test different configurations. In this way, the combined use of the COCO simulator and the model of a reverse osmosis unit proved to be a useful tool for comparing the performance of different process configurations.The Spanish Ministry of Economy and Competitiveness is kindly acknowledged (Project CTM 2010-20248).Gozálvez Zafrilla, JM.; Santafé Moros, MA.; Sanchis Sebastiá, M.; Gomis Fons, J. (2014). Implementation of membrane models on a CAPE-OPEN tool to simulate a process including RO membranes. Desalination and Water Treatment. 1-7. https://doi.org/10.1080/19443994.2014.995718S17Sharaf Eldean, M. A., & Soliman, A. M. (2013). A new visual library for modeling and simulation of renewable energy desalination systems (REDS). Desalination and Water Treatment, 51(37-39), 6905-6920. doi:10.1080/19443994.2013.777369Choi, Y.-J., Hwang, T.-M., Oh, H., Nam, S.-H., Lee, S., Jeon, J., … Chung, Y. (2011). Development of a simulation program for the forward osmosis and reverse osmosis process. Desalination and Water Treatment, 33(1-3), 273-282. doi:10.5004/dwt.2011.2652Karabelas, A. J., Kostoglou, M., & Koutsou, C. P. (2015). Modeling of spiral wound membrane desalination modules and plants – review and research priorities. Desalination, 356, 165-186. doi:10.1016/j.desal.2014.10.002Peshev, D., & Livingston, A. G. (2013). OSN Designer, a tool for predicting organic solvent nanofiltration technology performance using Aspen One, MATLAB and CAPE OPEN. Chemical Engineering Science, 104, 975-987. doi:10.1016/j.ces.2013.10.033Testard, L., & Belaud, J.-P. (2005). A CAPE-OPEN based framework for process simulation solutions integration. European Symposium on Computer-Aided Process Engineering-15, 38th European Symposium of the Working Party on Computer Aided Process Engineering, 607-612. doi:10.1016/s1570-7946(05)80223-8Morales-Rodríguez, R., Gani, R., Déchelotte, S., Vacher, A., & Baudouin, O. (2008). Use of CAPE-OPEN standards in the interoperability between modelling tools (MoT) and process simulators (Simulis® Thermodynamics and ProSimPlus). Chemical Engineering Research and Design, 86(7), 823-833. doi:10.1016/j.cherd.2008.02.022Guria, C., Bhattacharya, P. K., & Gupta, S. K. (2005). Multi-objective optimization of reverse osmosis desalination units using different adaptations of the non-dominated sorting genetic algorithm (NSGA). Computers & Chemical Engineering, 29(9), 1977-1995. doi:10.1016/j.compchemeng.2005.05.002Senthilmurugan, S., Ahluwalia, A., & Gupta, S. K. (2005). Modeling of a spiral-wound module and estimation of model parameters using numerical techniques. Desalination, 173(3), 269-286. doi:10.1016/j.desal.2004.08.034Chilyumova, E., & Thöming, J. (2007). Dynamic simulation of rinsing and regeneration networks based on high pressure RO. Desalination, 207(1-3), 45-58. doi:10.1016/j.desal.2006.07.00

Modelling and control of a continuous distillation tower through fuzzy techniques

This paper presents a methodology for the design of a fuzzy controller applicable to continuous processes based on local fuzzy models and velocity linearizations. It has been applied to the implementation of a fuzzy controller for a continuous distillation tower. Continuous distillation towers can be subjected to variations in feed characteristics that cause loss of product quality or excessive energy consumption. Therefore, the use of a fuzzy controller is interesting to control process performance.A dynamic model for continuous distillation was implemented and used to obtain data to develop the fuzzy controller at different operating points. The fuzzy controller was built by integration of linear controllers obtained for each linearization of the system. Simulation of the model with controller was used to validate the controller effectiveness under different scenarios, including a study of the sensibility of some parameters to the control.The results showed that the fuzzy controller was able to keep the target output in the desired range for different inputs disturbances, changing smoothly from a predefined target output to another. The developed techniques are applicable to more complex distillation systems including more operating variablesThe authors acknowledge the partial funding of this work by the projects: Regional Government Project GVPRE/2008/108, and National Projects DPI2007-66728-C02-01 and DPI2008-06737-C02-01.Barceló Rico, F.; Gozálvez Zafrilla, JM.; Diez Ruano, JL.; Santafé Moros, MA. (2011). Modelling and control of a continuous distillation tower through fuzzy techniques. Chemical Engineering Research and Design. 89(1):107-115. https://doi.org/10.1016/j.cherd.2010.04.015S10711589

Fluid Dynamic Modeling of Oxygen Permeation through Mixed Ionic-Electronic Conducting Membranes

[EN] The oxygen transport in a lab-scale experimental set-up for permeation testing of oxygen transport membranes has been modeled using computational fluid dynamics using Finite Element Analysis. The modeling considered gas hydrodynamics and oxygen diffusion in the gas phase and vacancy diffusion of oxygen in a perovskite disc-shaped membrane at 1273. K. In a first step, the model allowed obtaining the coefficient diffusion of oxygen. The parametric study showed that the set-up geometry and flow rate in the air compartment did not have major influence in the oxygen transport. However, very important polarization effects in the sweep-gas (argon) compartment were identified. The highest oxygen permeation flux and the lowest oxygen concentration on the membrane surface were obtained for the following conditions (in increasing order of importance): (1) a large gas inlet radius; (2) short gas inlet distance; and (3) a high gas flow rate. © 2011 Elsevier B.V.The Spanish Ministry for Science and Innovation (JAE-Pre 08-0058 grant and ENE2008-06302 project) and through FP7 NASA-OTM Project (NMP3-SL-2009-228701) is kindly acknowledged.Gozálvez-Zafrilla, JM.; Santafé Moros, MA.; Escolástico Rozalén, S.; Serra Alfaro, JM. (2011). Fluid Dynamic Modeling of Oxygen Permeation through Mixed Ionic-Electronic Conducting Membranes. Journal of Membrane Science. 378(1-2):290-300. https://doi.org/10.1016/j.memsci.2011.05.016S2903003781-

¿Interpretan los alumnos de ingeniería química los gráficos logarítmicos correctamente? Desarrollo de una herramienta para mejorar su precisión

[ES] La interpretación de gráficos logarítmicos es una habilidad importante en los profesionales de ingeniería. Dichos gráficos se utilizan para representar la evolución de fenómenos naturales y para facilitar el diseño de procesos y equipos. No obstante, los estudiantes están acostumbrados a leer datos en diagramas con escalas lineales, lo cual supone un reto en el aprendizaje de la lectura de otros tipos de representaciones. En el presente trabajo se evalúan las capacidades de interpretación de gráficos logarítmicos en estudiantes de tercer curso de grado de ingeniería química. El análisis sobre una muestra de 64 individuos revela que un 49% de los alumnos comete errores de interpretación, siendo los mas comunes la lectura de datos realizando una interpretación de escalas lineal y el conteo erróneo del número de líneas de división secundarias. Con el fin de facilitar el manejo de diagramas con escalas logarítmicas, se ha desarrollado un software de lectura de gráficos llamado PUNTGRAF. El programa permite calibrar distintos tipos de gráficos, y obtener las coordenadas de un punto. Se propone PUNTGRAF como una herramienta de apoyo en el aprendizaje de la interpretación de gráficos ingenieriles, que permita al alumno aprender de forma autónoma de sus propios errores.[EN] The interpretation of logarithmic plots is an important skill for engineers. Such graphical representations are widely used to show the evolution of natural phenomena and to facilitate the design of processes and equipments. The fact that engineering students are more familiar with the interpretation of linear-scale diagrams implies a challenge during the learning process of reading other types of representations. In the present work, the interpretation skills of logarithmic plots by chemical engineering undergraduates is evaluated. The analysis over a sample of 64 students reveals that 49% of them make reading mistakes, being the interpretation of linear scales and the incorrect count of minor grid lines the most common ones. With the aim of assisting the students with the use of logarithmic-scale plots, we have developed a software capable of reading values from different engineering plots; which we called PUNTGRAF. The program can be used to calibrate different types of charts and to obtain point coordinates. We propose PUNTGRAF as a useful tool to reinforce the interpretation skills of engineering plots by undergraduate students, which would help them to learn from their own mistakes in a self-training process.Martí-Calatayud, MC.; Santafé-Moros, MA.; Gozálvez-Zafrilla, JM. (2021). ¿Interpretan los alumnos de ingeniería química los gráficos logarítmicos correctamente? Desarrollo de una herramienta para mejorar su precisión. En In-Red 2020. VI Congreso nacional de innovación educativa y docencia en red. Editorial Universitat Politècnica de València. 1015-1024. https://doi.org/10.4995/INRED2020.2020.12003OCS1015102

Análisis estructural de los problemas orientado al aprendizaje de Operaciones de Separación

[EN] The subject Unit Operations of the Bachelor degree in Chemical Engineering is focused on learning the common operations used in chemical processes. After our experience, most of the students perceive that the subject is made up of independent learning units which requires the study of a great amount of theoretical concepts involving several unconnected calculations for each one, so they think the subject is tedious and complex. The reason is that they are not aware about the similarities among the unit operations. Besides, the procedures required to solve full exercises are hard for them and they misunderstood the reasoning process. A deep analysis of the exercises used to learning the unit operation calculations was carried out. Besides, the main features of mathematical software used (Mathcad) were considered. The aim is to do the reasoning process more visual, to facilitate the awareness of the transversality of the several unit operations and to reduce the time spent on the problem-solving. The result has been the restructuration of the exercise by means of “calculation areas” and the implementation of “function libraries”, which has improved the learning outcomes[ES] La asignatura Operaciones de Separación del Grado de Ingeniería Química se centra en el aprendizaje de las operaciones de mayor aplicación en procesos de ingeniería química. La falta de conciencia de las similitudes entre las distintas operaciones hace que una gran parte de los alumnos tenga la visión de que la asignatura está formada por unidades inconexas que requieren el estudio de muchos conceptos teóricos con cálculos diferenciados para todos ellos, de manera que les parece poco atractiva, compleja y voluminosa. La resolución de un problema completo les resulta, en general, larga y tienden a perderse en el proceso de razonamiento. Estas dificultades se han hecho más evidentes en los estudios de Grado, respecto a la misma asignatura de la anterior titulación de Ingeniero Químico. Por ello, se ha realizado un profundo análisis de los problemas utilizados para aprender los cálculos de cada operación, así como de las características del software utilizado en su resolución (Mathcad). Todo ello con el objetivo de hacer facilitar el proceso de razonamiento y la conciencia de transversalidad entre las distintas operaciones y de disminuir el tiempo requerido. Como resultado se han restructurado los problemas con el uso de “zonas de cálculo” y la creación de “librerías de funciones”, lo que ha supuesto una mejora en el aprendizaje.Los miembros del grupo ASEI agradecen al Vicerrectorado de Estudios y Convergencia Europea y al Instituto de Ciencias de Educación de la Universitat Politècnica de València la concesión del PIME A26/14 “Desarrollo de estrategias para la mejora del aprendizaje y evaluación de los problemas de Operaciones de Separación”Santafé Moros, MA.; Gozálvez Zafrilla, JM.; Navarro Laboulais, JJ. (2015). Análisis estructural de los problemas orientado al aprendizaje de Operaciones de Separación. En In-Red 2015 - CONGRESO NACIONAL DE INNOVACIÓN EDUCATIVA Y DE DOCENCIA EN RED. Editorial Universitat Politècnica de València. https://doi.org/10.4995/INRED2015.2015.1632OC

Adaptación de metodologías docentes para la enseñanza de problemas en aula informática con el objetivo de formar en competencias de nivel de Máster

[EN] This work analyzes the adaptation and development of teaching methodologies for problem solving strategies in the subject “Advanced Unit Operations” of the Master in Chemical Engineering for developing transversal key competences. As starting point, it has been used the teaching methodology developed in the former curriculum adapted to the new one. The adaptation was performed through two different ways. On the one hand, problems of open response supported by mathematical software were included. On the other hand, new computational resources, like simulation and design software, were introduced to make the student easier the exploration of different process alternatives. The inclusion of these problems implied changes in the evaluation procedure. The effects of the methodological changes performed are shown in relation with the acquired competences by the students and with the necessary changes in the evaluation procedure. A survey among the students shows a positive opinion in relation to the methodological adaptations performed.[ES] En este trabajo se analiza la adaptación y desarrollo de metodologías docentes para el aprendizaje de la resolución de problemas en la asignatura del Máster de Ingeniería Química “Operaciones de Separación Avanzadas” con el objetivo de desarrollar competencias transversales. Como punto de partida se considera la metodología que desarrollamos para las clases de problemas del plan de estudios previo. La adaptación se realizó a través de dos vías diferentes. Por una parte, se realizaron cambios en el tipo de problemas propuestos y en la forma de evaluación, trabajándose con problemas de tipo más abierto apoyados por software matemático. Por otra parte, se introdujeron nuevos recursos como programas de simulación y de diseño de procesos con el fin de facilitar al alumno la posibilidad de explorar alternativas. Los efectos de estos cambios se indican en este artículo relacionándolos con las competencias que favorecen y con los cambios en el sistema de evaluación necesarios. El análisis de los resultados de una encuesta mostró una opinión favorable hacia las adaptaciones metodológicas realizadas.Los autores agradecen al Vicerrectorado de Estudios y Convergencia Europea y al Instituto de Ciencias de Educación de la Universitat Politècnica de València la concesión del Proyecto de Innovación y Mejora Educativa PIME A26/14 “Desarrollo de estrategias para la mejora del aprendizaje y evaluación de los problemas de Operaciones de Separación”Gozálvez Zafrilla, JM.; Santafé Moros, MA.; Navarro Laboulais, JJ. (2015). Adaptación de metodologías docentes para la enseñanza de problemas en aula informática con el objetivo de formar en competencias de nivel de Máster. En In-Red 2015 - CONGRESO NACIONAL DE INNOVACIÓN EDUCATIVA Y DE DOCENCIA EN RED. Editorial Universitat Politècnica de València. https://doi.org/10.4995/INRED2015.2015.163

Operating Conditions Optimization via the Taguchi Method to Remove Colloidal Substances from Recycled Paper and Cardboard Production Wastewater

[EN] Optimization of the ultrafiltration (UF) process to remove colloidal substances from a paper mill's treated effluent was investigated in this study. The effects of four operating parameters in a UF system (transmembrane pressure (TMP), cross-flow velocity (CFV), temperature and molecular weight cut-off (MWCO)) on the average permeate flux (J(v)), organic matter chemical oxygen demand (COD) rejection rate and the cumulative flux decline (SFD), was investigated by robust experimental design using the Taguchi method. Analysis of variance (ANOVA) for an L(9)orthogonal array were used to determine the significance of the individual factors, that is to say, to determine which factor has more and which less influence over the UF response variables. Analysis of the percentage contribution (P%) indicated that the TMP and MWCO have the greatest contribution to the average permeate flux and SFD. In the case of the COD rejection rate, the results showed that MWCO has the highest contribution followed by CFV. The Taguchi method and the utility concept were employed to optimize the multiple response variables. The optimal conditions were found to be 2.0 bar of transmembrane pressure, 1.041 m/s of the cross-flow velocity, 15 degrees C of the temperature, and 100 kDa MWCO. The validation experiments under the optimal conditions achievedJ(v), COD rejection rate and SFD results of 81.15 L center dot m(-2)center dot h(-1), 43.90% and 6.01, respectively. Additionally, SST and turbidity decreased by about 99% and 99.5%, respectively, and reduction in particle size from around 458-1281 nm to 12.71-24.36 nm was achieved. The field-emission scanning electron microscopy images under optimal conditions showed that membrane fouling takes place at the highest rate in the first 30 min of UF. The results demonstrate the validity of the approach of using the Taguchi method and utility concept to obtain the optimal membrane conditions for the wastewater treatment using a reduced number of experiments.Sousa, MRS.; Lora-García, J.; López Pérez, MF.; Santafé Moros, MA.; Gozálvez-Zafrilla, JM. (2020). Operating Conditions Optimization via the Taguchi Method to Remove Colloidal Substances from Recycled Paper and Cardboard Production Wastewater. Membranes. 10(8):1-22. https://doi.org/10.3390/membranes10080170S122108Sevimli, M. F. (2005). Post-Treatment of Pulp and Paper Industry Wastewater by Advanced Oxidation Processes. Ozone: Science & Engineering, 27(1), 37-43. doi:10.1080/01919510590908968Key Statistics Report 2017|CEPI-CONFEDERATION OF EUROPEAN PAPER INDUSTRIEShttp://www.cepi.org/keystatistics2017Rajkumar, K. (2016). An Evaluation of Biological Approach for the Effluent Treatment of Paper Boards Industry - An Economic Perspective. Journal of Bioremediation & Biodegradation, 7(5). doi:10.4172/2155-6199.1000366AHMAD, A., WONG, S., TENG, T., & ZUHAIRI, A. (2008). Improvement of alum and PACl coagulation by polyacrylamides (PAMs) for the treatment of pulp and paper mill wastewater. Chemical Engineering Journal, 137(3), 510-517. doi:10.1016/j.cej.2007.03.088Temmink, H., & Grolle, K. (2005). Tertiary activated carbon treatment of paper and board industry wastewater. Bioresource Technology, 96(15), 1683-1689. doi:10.1016/j.biortech.2004.12.035Zhang, Q., & Chuang, K. T. (2001). Adsorption of organic pollutants from effluents of a Kraft pulp mill on activated carbon and polymer resin. Advances in Environmental Research, 5(3), 251-258. doi:10.1016/s1093-0191(00)00059-9Catalkaya, E. C., & Kargi, F. (2008). Advanced oxidation treatment of pulp mill effluent for TOC and toxicity removals. Journal of Environmental Management, 87(3), 396-404. doi:10.1016/j.jenvman.2007.01.016Pérez, M., Torrades, F., Garcı́a-Hortal, J. 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