Yes / The successful use of Reverse Osmosis (RO) process has increased significantly in water desalination, water treatment and food processing applications. In this work, the economic feasibility of a multi-stage RO process including both retentate and permeate reprocessing for the removal of chlorophenol from wastewater is explored using simulation and optimisation studies. Firstly, a mathematical model of the process is developed based on the solution diffusion model, which was validated using experimental chlorophenol removal from the literature, is combined with several appropriate cost functions to form a full model package. Secondly, for a better understanding of the interactions between the different parameters on the economic performance of the process, a detailed process simulation is carried out. Finally, a multi-objective optimisation framework based on Non-Linear Programming (NLP) problem is developed for minimising the product unit cost, the total annualised cost, the specific energy consumption together with optimising the feed pressure and feed flow rate for an acceptable level of chlorophenol rejection and total water recovery rate. The results clearly show that the removal of chlorophenol can reach 98.8% at a cost of approximately 0.21 $/m³.

No / Multi Effect Distillation (MED) and Reverse Osmosis (RO) processes have been extensively used to produce freshwater from seawater resources. amongst many performance indicators, energy consumption of different configuration of hybrid system of MED and RO processes have been analysed in the past. Hybrid MED-RO system is energy intensive and use of fossil fuel can significantly increase the carbon footprint, unless stable renewable energy sources are used. In this work specific energy consumption of a simple hybrid MED-RO system with permeate reprocessing is minimised while optimising a number of operating decision variables using model based optimisation technique. A detailed process model developed earlier by the authors is embedded in the optimisation framework resulting in a constrained Non-linear Programming (NLP) problem. The minimum specific energy consumption achieved in this work is about 18% lower than what is reported in the literature resulting in a significant energy saving and thus carbon footprint.

Yes / Reverse Osmosis (RO) membrane process has been commonly used for clarification and concentration of apple juice processes, due to significant advance in membrane technology, requirements for low energy and cost, and effective retention of aroma components. In this paper, a multi-stage RO industrial full-scale plant based on the MSCB 2521 RE99 spiral-wound membrane module has been used to simulate the process of concentrating apple juice and to identify an optimal multi-stage RO process for a specified apple juice product of high concentration measured in Brix. The optimisation problem is formulated as a Nonlinear Programming (NLP) problem with five different RO superstructures to maximise the apple juice concentration as well as the operating parameters such as feed pressure, flow rate and temperature are optimised. A simple lumped parameter model based on the solution-diffusion model and the contribution of all sugar species (sucrose, glucose, malic acid, fructose and sorbitol) to the osmotic pressure is assumed to represent the process. The study revealed that the multi-stage series RO process can optimise the product concentration of apple juice better than other configurations. It has been concluded that the series configuration of twelve elements of 1.03 m2 area improves the product apple juice concentration by about 142% compared to one element. Furthermore, the feed pressure and flow rate were found to have a significant impact on the concentration of the apple juice.

Yes / The integration of two or more processes in a hybrid system is one of the most desirable options to provide flexibility, interoperability and data sharing between the connected processes. Various examples of hybrid systems have been developed with coherent seawater desalination systems such as the combination of thermal and membrane technologies. This paper focuses on the simulation and optimisation of an integrated (hybrid) system of multi effect distillation and double Reverse Osmosis (RO) processes to produce different grades of water needed in a smart city from seawater resources. The optimisation-based model investigates five scenarios to obtain the highest productivity of drinking water, irrigation water, water for livestock and power plant water, whilst constraining the product water salinity to be within the required standards and with lowest specific energy consumption. For this purpose, multi objective optimisation problem was formulated using the gPROMS (general Process Modelling System) software. The results confirm the superiority of the developed hybrid system to sustain different grades of water in a smart city.

Yes / The Reverse Osmosis (RO) input parameters have key roles in mass transport and performance indicators. Several studies can be found in open literature. However, an experimental research on evaluating the brackish water RO input parameters influence on the performance metrics with justifying the interference between them via a robust model has not been addressed yet. This paper aims to design, construct, and experimentally evaluate the performance of a 50 m3/d RO pilot-plant to desalinate brackish water in Shahid Chamran University of Ahvaz, Iran. Water samples with various salinity ranging from 1000 to 5000 ppm were fed to a semi-permeable membrane under variable operating pressures from 5 to 13 bar. By evaluating permeate flux and brine flowrate, permeate and brine salinities, membrane water recovery, and salt rejection, some logical relations were derived. The results indicated that the performance of an RO unit is largely dependent on feed pressure and feed salinity. At a fixed feed concentration, an almost linear relationship was found to relate feed pressure and both permeate and brine flowrates. Statistically, it was found that 13 bar feed pressure results in a maximum salt rejection of 98.8% at a minimum permeate concentration of 12 ppm. Moreover, 73.3% reduction in permeate salinity and 30.8% increase in brine salinity are reported when feed pressure increases from 5 to 13 bar. Finally, it is concluded that the water transport coefficient is a function of feed pressure, salinity, and temperature, which is experimentally estimated to be 2.8552 L/(m2 h bar).

Yes / In this research, the effect of operating parameters on the fresh water production cost of hybrid Multi Effect Distillation (MED) and Reverse Osmosis (RO) system is investigated. To achieve this, an earlier comprehensive model developed by the authors for MED + RO system is combined with two full-scale cost models of MED and RO processes collected from the literature. Using the economic model, the variation of the overall fresh water cost with respect to some operating conditions, namely steam temperature and steam flow rate for the MED process and inlet pressure and flow rate for the RO process, is accurately investigated. Then, the hybrid process model is incorporated into a single-objective non-linear optimisation framework to minimise the fresh water cost by finding the optimal values of the above operating conditions. The optimisation results confirm the economic feasibility of the proposed hybrid seawater desalination plant.

Yes / Reverse osmosis (RO) is becoming one of the most promising technologies used in wastewater treatment because it offers high rate of contaminant rejection and lower energy consumption in comparison with other thermal treatment processes. Earlier research by the same authors in respect of a distributed one-dimensional mathematical model for a single spiral-wound RO membrane module based on the solution-diffusion model has been used in this paper to simulate the rejection of NDMA (N-nitrosodimethylamine) from wastewater in a series of seven RO elements full-scale treatment plant. Firstly, the applicability of this model has been evaluated using a simulation study and the results have been compared against experimental data gathered from the literature for a given plant. Secondly, further simulation and analysis studies are carried out to assess the performance of the plant for NDMA rejection and recovery rate under different operating conditions of feed pressure, flow rate, and concentration. For the studied RO configuration, it is concluded that a maximum of 55.1% NDMA rejection can be achieved, which confirms the remaining issue of lower NDMA rejection.

Yes / In this work, we considered model-based simulation and optimisation of a medium scale brackish water desalination process. The mathematical model is validated using actual multistage RO plant data of Al- Hashemite University (Jordan). Using the validated model, the sensitivity of different operating parameters such as pump pressure, brackish water flow rate and seasonal water temperature (covering the whole year) on the performance indicators such as productivity, product salinity and specific energy consumption of the process is conducted. For a given feed flow rate and pump pressure, winter season produces less freshwater that in summer in line with the assumption that winter water demand is less than that in summer. With the soaring energy prices globally, any opportunity for the reduction of energy is not only desirable from the economic point of view but is an absolute necessity to meet the net zero carbon emission pledge by many nations, as globally most desalination plants use fossil fuel as the main source of energy. Therefore, the second part of this paper attempts to minimise the specific energy consumption of the RO system using model-based optimisation technique. The study resulted not only 19 % reduction in specific energy but also 4.46 % increase in productivity in a particular season of the year. For fixed product demand, this opens the opportunity for scheduling cleaning and maintenance of the RO process without having to consider full system shutdown.

La prolongation de l’intervalle électrocardiographique QT est un facteur de risque d’arythmie ventriculaire et de mort subite. Cette anomalie, retrouvée chez certains patients atteints de lupus érythémateux disséminé, pourrait contribuer à la mortalité cardiovasculaire élevée dans cette population. L’anti-Ro/SSA, un auto-anticorps retrouvé chez environ 30% des patients atteints de lupus, est associé à la présence de blocs cardiaques chez le nouveau-né et pourrait aussi augmenter le risque de prolongation pathologique de l’intervalle QT chez l’adulte. Le présent mémoire est constitué de cinq chapitres traitant de l’association potentielle entre l’anticorps anti-Ro/SSA et la prolongation de l’intervalle QT. Le premier chapitre constitue une introduction permettant de mettre en contexte les éléments essentiels à la compréhension du projet d’étude. Le deuxième chapitre constitue une revue de l’état des connaissances actuelles sur le lien potentiel entre anti-Ro/SSA et intervalle QT. Le troisième chapitre présente le projet d’étude par l’intermédiaire d’un article publié dans Arthritis Care and Research. Dans cette étude, les patients de la cohorte de lupiques du Centre Universitaire de santé McGill ont subi des électrocardiogrammes dans l’objectif d’estimer l’association entre l’anti-Ro/SSA et les anomalies électrocardiographiques, en tenant compte d’autres facteurs démographiques et cliniques. L’association entre la prolongation de l’intervalle QT et la présence de l’anti-Ro/SSA a été démontrée (rapports de cotes ajustés de 5.1 à 12.6) et les patients porteurs de l’anti-Ro/SSA pourraient donc bénéficier de dépistage électrocardiographique systématique. Les points faibles et forts de cet article sont discutés dans le quatrième chapitre et des perspectives de recherches futures sont finalement abordées. / QT interval prolongation on the electrocardiogram is a risk factor for ventricular arrhythmias and sudden cardiac death. This abnormality is found in patients with systemic lupus erythematosus and could contribute to the high cardiovascular mortality rate in this population. Anti-Ro/SSA is an auto-antibody presents in about 30% of lupus patients and is associated with congenital cardiac block. This auto-antibody could also increase the risk of pathologic prolongation of the QT interval in adults. This master’s thesis is comprised of five chapters discussing the potential association between anti-Ro/SSA antibody and QT interval prolongation. The first chapter is an introduction to the essential elements for the understanding of the study project. The second chapter is a literature review of the potential link between anti-Ro/SSA and QT interval prolongation. The third chapter presents the study project through an article published in Arthritis Care and Research. In this study, patients from the McGill lupus cohort were invited to undergo electrocardiograms in order to estimate the association between anti-Ro/SSA antibody and electrocardiographic abnormalities, while taking into account the other potentially associated demographic and clinical factors. This study shows an association between anti-Ro/SSA and prolonged QT interval (Odds ratios: 5.1 to 12.6) and patients positive for anti-Ro/SSA may thus benefit from electrocardiographic testing. Strengths and weaknesses of this article are discussed in the fourth chapter and future research areas are finally explored.

La prolongation de l’intervalle électrocardiographique QT est un facteur de risque d’arythmie ventriculaire et de mort subite. Cette anomalie, retrouvée chez certains patients atteints de lupus érythémateux disséminé, pourrait contribuer à la mortalité cardiovasculaire élevée dans cette population. L’anti-Ro/SSA, un auto-anticorps retrouvé chez environ 30% des patients atteints de lupus, est associé à la présence de blocs cardiaques chez le nouveau-né et pourrait aussi augmenter le risque de prolongation pathologique de l’intervalle QT chez l’adulte. Le présent mémoire est constitué de cinq chapitres traitant de l’association potentielle entre l’anticorps anti-Ro/SSA et la prolongation de l’intervalle QT. Le premier chapitre constitue une introduction permettant de mettre en contexte les éléments essentiels à la compréhension du projet d’étude. Le deuxième chapitre constitue une revue de l’état des connaissances actuelles sur le lien potentiel entre anti-Ro/SSA et intervalle QT. Le troisième chapitre présente le projet d’étude par l’intermédiaire d’un article publié dans Arthritis Care and Research. Dans cette étude, les patients de la cohorte de lupiques du Centre Universitaire de santé McGill ont subi des électrocardiogrammes dans l’objectif d’estimer l’association entre l’anti-Ro/SSA et les anomalies électrocardiographiques, en tenant compte d’autres facteurs démographiques et cliniques. L’association entre la prolongation de l’intervalle QT et la présence de l’anti-Ro/SSA a été démontrée (rapports de cotes ajustés de 5.1 à 12.6) et les patients porteurs de l’anti-Ro/SSA pourraient donc bénéficier de dépistage électrocardiographique systématique. Les points faibles et forts de cet article sont discutés dans le quatrième chapitre et des perspectives de recherches futures sont finalement abordées. / QT interval prolongation on the electrocardiogram is a risk factor for ventricular arrhythmias and sudden cardiac death. This abnormality is found in patients with systemic lupus erythematosus and could contribute to the high cardiovascular mortality rate in this population. Anti-Ro/SSA is an auto-antibody presents in about 30% of lupus patients and is associated with congenital cardiac block. This auto-antibody could also increase the risk of pathologic prolongation of the QT interval in adults. This master’s thesis is comprised of five chapters discussing the potential association between anti-Ro/SSA antibody and QT interval prolongation. The first chapter is an introduction to the essential elements for the understanding of the study project. The second chapter is a literature review of the potential link between anti-Ro/SSA and QT interval prolongation. The third chapter presents the study project through an article published in Arthritis Care and Research. In this study, patients from the McGill lupus cohort were invited to undergo electrocardiograms in order to estimate the association between anti-Ro/SSA antibody and electrocardiographic abnormalities, while taking into account the other potentially associated demographic and clinical factors. This study shows an association between anti-Ro/SSA and prolonged QT interval (Odds ratios: 5.1 to 12.6) and patients positive for anti-Ro/SSA may thus benefit from electrocardiographic testing. Strengths and weaknesses of this article are discussed in the fourth chapter and future research areas are finally explored.