A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering, 2016 / The aim of this research was to reduce heavy metal and sulfate content of acid mine drainage (AMD) through the methods of passive filtration by combining permeable concrete and organic materials. This was to achieve a low cost, yet effective temporary treatment method for rural/poor communities who are affected by AMD. The acids are filtered through layers of alternating pervious concrete and biological composting layers. The concrete layers target removal of heavy metals such as iron, manganese, potassium, and magnesium, etc. through precipitation as well as reduce sulfate content to a small degree along with total dissolved solids. The concrete layers also aid in raising the pH of the AMD to more acceptable levels. The biological layers achieve sulfate remediation through the metabolism of sulfatereducing- bacteria (SRB). This process however required time and the organic layers were thus thicker and less permeable than the concrete layers in order to allow seepage to take place at a reduced rate. A wide variation of composting layers were tested, including cow manure, chicken manure, sawdust, straw, zoo manure, and leaf compost to find an optimum mix of materials which allows for the greatest sulfate reduction through sulfate reducing bacteria in the shortest possible time. Short as well as Long-term testing of rigs was undertaken to establish effectiveness, limitations and lifespan of the filtration systems. AMD from a mine in the Mpumalanga coal fields with exceptionally high sulfate content was used to test effectiveness of the organic materials over a short period of time. With long term testing conducted with a synthetic AMD, due to limited supply from the mine. The short term testing yielded removal of sulfates in the order of 56% when using kraal manure as the biological reagent mixed with sawdust for added organic carbon. The mix percentages by volume were 80%Sawdust to 20%manure and this setup was able to achieve the 56% removal of sulfates within 14 days. The filter also successfully raised the pH to 8 while removing a significant portion of heavy metals. The long term tests showed complete (100%) remediation of sulfates after a period of approximately sixty days. The tests are continuing to determine their finite lifespan and limitations. The results show promise for using the technology as a low cost, temporary measure to protect locally impacted groundwater, especially for isolated and/or rural communities while a permanent long term solution is sought.

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. August, 2017 / The foremost aim of potable water treatment is to produce water that does not pose a health risk when consumed and/or otherwise used. Nevertheless, research has established that the quality of treated water deteriorates during distribution. The nature and extent of this deterioration varies from system to system and from time to time. The aim of this research study was to monitor the parameters that are known to significantly affect biostability and biofilm formation potential in drinking water distribution systems. Biweekly water samples were collected from thirteen sites, across a section of Johannesburg Water’s network, between September 2015 and August 2016. All samples were assayed for a suite of fifteen water quality parameters using standard methods. Heightened temperature, dearth of chlorine residuals, availability of biodegradable dissolved organic carbon (BDOC), and advanced water age all engendered the loss of biostability (instability). Biostability controlling parameters varied seasonally and spatially. Samples collected during spring and summer, in general, were most likely to be characterized by instability than samples collected during winter and autumn. Samples collected from sites RW80, RW81, RW82, RW83, RW104 and RW253 were more prone to instability compared to samples from other sites. From the results, it is clear that chlorine residuals ought to be kept above 0.2 mg/l, and, BDOC below 0.3mg/l to prevent the loss of heterotrophic stability in distributed water. BDOC concentrations can be decreased by, flushing the pipes, cleaning reservoirs regularly and by further treating feed water before distributing. Booster disinfection can be relied upon to ensure that chlorine residuals are maintained throughout the network. Apart from potential health risks, biological instability and biofilm growth can result in non-compliance with regulations. / MT2018

MSc report presented to the University of the Witwatersrand In the fulfillment of the requirements for the degree of Master of Science in Engineering School of Chemical and Metallurgical Engineering Faculty of Engineering and the Built Environment University of the Witwatersrand Johannesburg April 2017 / Oil and gas operations produce high volumes of wastewater in the form of finely dispersed oil/ water (o/w) emulsions, which have detrimental effects on the environment. The current most feasible method used to mitigate the environmental impacts caused by the emulsion (produced water) from oil and gas operations is polymer membrane technology. However, polymer membranes are susceptible to fouling and concentration polarization, which leads to the necessity for frequent membrane replacement, thus loss of operating time and high operation cost. This motivates the need to investigate ways of modifying the polymer membrane in order to make it more resistant to fouling and concentration polarization. This study is concerned with circumventing the challenges experienced by polymer membrane during crude oil/ water mixture ultra-filtration by infusing the polymer membrane with nano particles. The aim of the research was to investigate the influence of addition of CNTs on the modified membranes in treatment of waste water from petroleum source. The Wet Impregnation method was used for the preparation of the bimetallic catalyst (Fe-Co catalyst supported on Zeolite), Chemical vapor deposition (CVD) method was used to prepare the carbon nanotubes (CNTs) and Phase inversion (PI) method was used for the preparation of the polymer nanocomposite membrane. The bimetallic catalyst was characterized using scanning electron microscope (SEM) and X-ray diffraction (XRD). The CNTs were characterized using Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). The prepared polymer nanocomposite membranes were characterized using SEM, FTIR, goniometer (for contact angles) and TAXT plus texture analyzer (for tensile strength test). Functionalized carbon nanotubes were used as membrane fillers or modifiers to improve the filtration properties of the polymeric membrane, ultimately forming nanocomposite polymer membranes. This increased hydrophilicity, chemical, mechanical and physical properties of the polymer membrane, made them to perform better during filtration than pristine polymer membranes. The performance of the nanocomposite membranes were evaluated and it was determined that the nanocomposite polymer membrane with a loading 0.4 wt.% functionalized carbon nanotubes performed better than pristine membrane and other CNTs loaded nanocomposite polymer membranes. The pristine membrane (0 wt% CNTs) showed a higher contact angle (79o) which crosses ponds to the inability to soak up water. The 0.4 wt% nanocomposite polymer membrane showed the lowest contact angle of 72 o, this validated an improvement in the properties of the membrane, in particular hydrophilicity. The 0.4 wt% nanocomposite polymer membrane showed a superior mechanical strength, with a breaking force at 4 N relative to the other membranes of the same thickness. 0.4 wt% nanocomposite polymer membrane showed the highest permeate flux of 120 L/m2.h compared to the pristine membrane, which showed a permeate flux of 63 L/m2.h. The permeate flux of 0.4 wt% nano-composite polymer membrane increased with the operating pressure. / MT 2018

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg 2016 / Horizontal subsurface flow constructed wetlands (HSSF CWs) are being considered in South Africa as an alternative waste water treatment technology which is low in capital costs and typically requires less operational infrastructure when compared to conventional treatment technologies. HSSF CWs may thus be a potential solution for solving the challenge of ensuring reliable access to clean water for rural communities whose municipalities may not be able to afford the construction of a waste water treatment plant as well as not being able to supply sufficient technical expertise for the operation thereof. Proper design of HSSF CWs requires a detailed investigation into the hydraulic behaviour as it has a direct effect on the treatment performance in these systems. In this study, three available hydraulic modelling methodologies for HSSF CWs were compared and these are the impulse, step change integral and step change derivative modelling methodologies. Hydraulic data were generated from planted and unplanted pilot scale HSSF CWs using residence time distribution (RTD) studies and the modelling results using each methodology were compared. It was found that each methodology was capable of suggesting a different hydraulic behaviour for the same system being studied and since it is not possible to evaluate an analytical answer to the problem independently it was not possible to determine which modelling methodology was the most accurate. Practical limitations of the experiments used to feed hydraulic data to the respective methodologies were also highlighted. Despite a well-designed sampling regime it was not possible to capture sufficient data surrounding the peak of the impulse response curve and may have impacted negatively on the modelling results. No such difficulties were encountered with the step change tracer experiments. The mathematical techniques which each methodology employs were also critically assessed. It was found that numerical differentiation in the step change derivative modelling approach introduced noise into the RTD curve and may have affected subsequent results. Ultimately each methodology has its own associated strengths and weaknesses and choice of methodology may be dictated by other factors such as cost to set up the hydraulic experiment as well as equipment availability. Tasks two and three of this dissertation dealt with how Biomimicry can be used as a tool to develop more sustainable HSSF CW designs and hydraulic modelling processes. In task two, hydraulic data generated from the first task were used to develop estimates of the velocity profiles inside a planted HSSF CW to identify regions most prone to clogging, a phenomenon which would be a serious concern for rural communities whose sole water treatment system would be the CW. Biomimetic design principles were combined with the modelling results to develop a modular system design allowing for sections of the CW to be removed for cleaning while still allowing for continuous treatment of the waste water. Task three explored the use of heat as a hydraulic tracer. Heat is considered more environmentally friendly when compared to chemicals as tracers as the CW can equilibrate to ambient conditions post study and the effluent does not require dedicated disposal infrastructure. Heat is non-conservative in these systems and processes such as absorption by the subsurface media and loss to the surroundings distort the hydraulic response curve from which the hydraulic behaviour cannot be directly obtained. In this study a mathematical model was developed which maps a heat tracer response curve to one which would be obtained if a conservative chemical tracer were used. It was tested by conducting a combined heat-chemical tracer study on an unplanted laboratory-scale HSSF CW and the predicted chemical response curve was compared with the actual experimental response curve. The model performed satisfactorily indicated by a 5% and 6% relative difference in the Peclet number (Pe) and mean of the RTD respectively. In each of these chapters, an abstract is provided which summarizes the main findings of the study. / MT2017

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2018. / A membrane distillation crystallization (MDC) experimental setup was designed, constructed and commissioned with rectangular mixing crystallizer tanks. The advantages and disadvantages of a rectangular mixing tank are compared to the traditional cylindrical mixing tank with baffling by means of a computational fluid dynamic (CFD) analysis in Ansys Fluent. The effect of tank configuration and geometry on the hydrodynamic and mixing characteristics for efficient momentum, solid suspension, heat and mass transfer were investigated. The hydrodynamic conditions in a crystallizer-mixing tank determine the quality of fluid mixing essential for optimal crystallization. Forty-five degree pitched blade turbines (PBT) were used to provide the agitation in the stainless steel rectangular jacketed tanks. Clear polycarbonate replicas of the rectangular tanks were manufactured to visually observe the mixing process in the tanks. Silica particles were used to represent the calcium carbonate crystals in the experiment. The data gathered from these experiments showed that the tanks should be operated between 600 to 750 rpm in the CFD simulations to simulate partial to complete suspension. In the numerical simulations a rectangular tank was compared to a cylindrical tank with baffling of the same volume. The partial differential equations solved in the numerical simulation were the conservation of mass (continuity), conservation of momentum and additional turbulence equations. In order to solve the turbulent fluid flow characteristics, the industry standard two-equation model, namely the K-epsilon model was used. This model was refined by the addition of the Wen-Yu drag model, the Simonin turbulent dissipation and the Simonin et al. turbulence interaction models. The RANS based RNG (k-ε), derived from the instantaneous Navier-Stokes equation was selected as the preferred model to analyse the hydrodynamic flow fields in the tanks. The 3D sliding mesh method was used to compute a time accurate solution. The Eulerian-granular multiphase model was used to predict the degree of solids suspension in the tanks. The efficiency of mixing within the tank was measured by the tank’s ability to keep the crystals in suspension and preventing any particle from settling at the bottom for more than 1-2 second(s). The mixing tanks were initially loaded with 5% v/v, which equates to a loaded height of approximately 10 mm. The simulations were done with the use of the volume fraction function to visually observe the cloud height and gauge the homogeneity and distribution of the particulates within the fluid flow fields. The results from the experimental setup were compared to the CFD simulations to qualify the use of CFD simulations for the comparison of the geometrically different tanks. Lastly, the findings from the CFD simulations were used to compare the tanks and determine if the rectangular tank built for the MDC experiment perform satisfactorily to replace a standard cylindrical tank with baffling for this application.

Digitized by Kansas Correctional Industries

This final thesis goal has been to try and develop a titanium dioxide coating for water purification. The coating should be used in a manufacturing industry on textiles. Water purification is achieved through photocatalysis with titanium dioxide and UV-radiation, where hydroxyl radicals form through oxidation. The kind of textile fiber chosen for the substrates is a polyester fiber. The substrates have been developed in several different shapes. Two different knitted patterns was developed, one flat patterned and one wavy patterned. Another kind of substrate was a spacer-type and there was also a substrate made from a PET-bottle. The different substrates were chosen to compare the different coatings effect on different surfaces and the different coatings were developed from two types of titanium dioxide. The coated substrates have been analyzed for hydroxyl radical generating properties. By testing a sample of water with titanium dioxide against a sample with water that had no additives, it was shown that titanium dioxide generates more hydroxyl radicals. The results of the work showed that the recipe containing 3 % titanium dioxide and 3 % acrylic binder showed good properties for water purification. In addition, the results showed a stronger effect for the wavy patterned substrate then the flat patterned, which is an interesting result that should be researched further in the future. / Program: Textilingenjörsutbildningen

A serragem de madeira é um produto proveniente do uso da madeira, que pode ter aproveitamento econômico, transformando-se e agregando valor a cadeia produtiva da madeira. Uma de suas aplicações pode ser a produção de carvão e bio-óleo. O carvão ativado tem um custo elevado, porém é uma opção que apresenta potencial de adsorção e remoção de cianotoxinas e matéria orgânica presentes em água de abastecimento. O objetivo deste trabalho foi analisar a qualidade do carvão de serragem e seu potencial para ser aplicado em sistema de purificação de água, através de parâmetros físico/químicos. A serragem foi caracterizada conforme sua composição química, quanto ao teor de lignina, (38%); Hemicelulose (17,8%), holocelulose (53,9%), analises elementar: Carbono (48,3%), Hidrogênio (5,09%), Nitrogênio (0,25%), Oxigênio (46,36%) e imediatas: Cinzas (0,19%), Umidade (4,52%), Material Volátil (90,39%) e carbono fixo (4,9%) para ser utilizada como matéria prima na produção de carvão em reator de leito fixo. As variáveis utilizadas para obtenção do melhor rendimento dos produtos foram: temperatura, taxa de aquecimento, tempo e vazão do gás, de acordo com o planejamento fatorial 24-1. Além da produção, a qualidade do carvão foi verificada por meio de análise imediata: Cinzas (3,42%), Umidade (2,29%), Material volátil (41,04%) e carbono fixo (53,04%). Análise elementar: Carbono (74,36%), Hidrogênio (2,96%), Nitrogênio (0,55%) e oxigênio (22,13%). As análises de microscopia eletrônica de varredura (MEV), Índice de Azul de Metileno e BET que mostraram que o carvão consiste de microporos com uma área superficial de 1,43819 m²/g evidenciando a existência e a qualidade dos poros presentes no carvão. A eficiência na remoção de matéria orgânica presente na água, foi avaliada utilizando-se filtros descendentes com o carvão obtido. Características físico-químicas e microbiológica da amostra de água foram avaliadas antes e após a filtração. Notou-se que o tempo de saturação do carvão de serragem aconteceu após 10 horas de funcionamento dos filtros, sendo que a maior eficiência na remoção de matéria orgânica ocorreu nas primeiras 3 horas. / Sawdust is a product derived from the use of wood, which can be used economically, transforming and adding value to the productive chain of wood. One of its applications may be the production of coal and bio-oil. Activated carbon has a high cost, but it is an option that presents potential of adsorption and removal of cyanotoxins and organic matter present in water supply. The objective of this work was to analyze the quality of sawdust and its potential to be applied in a water purification system, through physical / chemical parameters. The sawdust was characterized according to its chemical composition, in terms of lignin content (38%); Hemicellulose (17.8%), holocellulose (53.9%), elemental analysis: Carbon (48.3%), Hydrogen (5.09%), Nitrogen (0.25%), Oxygen and immediate: Ash (0.19%), Moisture (4.52%), Volatile Material (90.39%) and fixed carbon (4.9%) to be used as raw material for coal production in bed reactor fixed. The variables used to obtain the best product yield were: temperature, heating rate, time and gas flow, according to factorial design 24-1. In addition to the production, coal quality was verified through immediate analysis: Ash (3.42%), Moisture (2,29%), Volatile material (41.04%) and fixed carbon (53.04%). Elemental analysis: Carbon (74.36%), Hydrogen (2.96%), Nitrogen (0.55%) and oxygen (22.13%). The scanning electron microscopy (SEM), Methylene Blue Index and BET analyzes showed that the coal consists of micropores with a surface area of 1.43819 m² / g evidencing the existence and the quality of the pores present in the coal. The efficiency of removal of organic matter present in the water was evaluated using downstream filters with the obtained carbon. Physical-chemical and microbiological characteristics of the water sample were evaluated before and after filtration. It was observed that the saturation time of sawdust occurred after 10 hours of filter operation, and the highest efficiency in the removal of organic matter occurred in the first 3 hours.

Orientador: Giuseppina Pace Pereira Lima / Coorientador: Juan Saavedra del Aguila / Banca: Fabio Vianello / Banca: Francisco Artes Calero / Banca: Camila Renata Correa Camacho / Banca: Igor Otavio Minatel / Resumo: O objetivo deste estudo foi verificar a influencia de sanitizantes (ozônio e hipoclorito de sódio) no conteúdo de compostos bioativos e na atividade antioxidante durante o armazenamento refrigerado e na simulação de comercialização de mangas (Mangifera indica L.) 'Palmer' cultivadas em sistema orgânico e convencional e verificar as alterações durante o armazenamento de dois diferentes smoothies. Para atingir esse objetivo a tese foi dividida em cinco capítulos, no primeiro as mangas 'Palmer' orgânicas adquiridas no município de Borborema-SP e as convencionais, doadas pela Ogata Citrus (Taquaritinga-SP) foram transportadas ao laboratório de Bioquímica, onde foram submetidas a quatro tratamentos de imersão: imersão em água; em água clorada com 100 mg L-1 de hipoclorito de sódio por 10 minutos e em água ozonizada por 10 ou 20 minutos. As avaliações foram realizadas após a colheita e aos 7 e 15 dias de armazenamento refrigerado. Aos 7 dias, os frutos foram levados ao ambiente e as avaliações seguiram por 4 e 8 dias, para simular o período de comercialização. Determinaram-se a firmeza da polpa, pH, ácido ascórbico, sólidos solúveis, acidez titulável, polifenóis totais, flavonóides totais, β-caroteno, DPPH e FRAP. As análises microbiológicas foram realizadas após a colheita, aos 7 dias de armazenando refrigerado e aos 7 dias mais 4 em ambiente. O delineamento utilizado foi inteiramente casualizado (DIC) com esquema fatorial 5 x 8 (dias de avaliação x tratamentos) com 3 repetições. Houve uma tendência dos frutos orgânicos e ozonizados apresentarem maiores conteúdos dos compostos bioativos, com isso maior atividade antioxidante, o que evidenciou que o ozônio pode substituir o cloro sem prejuízos aos frutos. No segundo capitulo, foi realizada a quantificação das aminas bioativas das polpas de manga 'Palmer' orgânicas e convencionais, submetidas a ... / Abstract: The aim of this study was to investigate the influence of sanitizers (ozone and sodium hypochlorite) in the bioactive compounds content and antioxidant activity during cold storage and marketing simulation grown in mango (Mangifera indica L.) grown in organic and conventional system and verify changes during storage of two different smoothies. To achieve this thesis objective was divided into five sections, the first the mango 'Palmer' organic acquired in Borborema-SP and conventional, donated by Ogata Citrus (Taquaritinga-SP) were transported to the laboratory of Biochemistry, which were submitted four immersion treatments: immersion in water; in chlorinated water with 100 mg L-1 of sodium hypochlorite for 10 minutes and ozonated water for 10 and 20 minutes. The evaluations were performed after harvest and at 7 and 15 days of cold storage. At 7 days, fruit were taken to the environment and evaluations followed by 4 and 8 days, to simulate marketing period. Were determined firmness, pH, ascorbic acid, soluble solids, titratable acidity, total polyphenols, total flavonoids, β-carotene, DPPH and FRAP. The microbiological analyzes were carried out after harvest, after 7 days of cold storage and 7 days over 4 environment. The design was completely randomized (CRD) with factorial 5 x 8 (day trial x treatments) with three repetitions. There was a trend of organic fruit and ozonated have higher bioactive compounds contents, therefore higher antioxidant activity, which shows that ozone could replace chlorine without damage to fruit. In the second chapter, it performed the bioactive amines quantification of the pulp mango 'Palmer' organic and conventional, undergo four sanitization treatments: immersion in the tap water; in chlorinated water with 100 mg L-1 of sodium hypochlorite for 10 minutes and ozonization for 10 and 20 minutes postharvest and after seven days of cold storage followed by 4 and 8 ... / Doutor

Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2018. / Globally, water is considered an essential resource as it sustains human, animal and plant life. Water is not only essential for all forms of life but imperative for economic growth. The world’s population is increasing at a disquieting rate, which will result in an increased demand for fresh water and food security. The agricultural industry is the main consumer of global freshwater and utilises fertilisers in order to meet food demands. The demand for water in South Africa (SA) has increased considerably due to the rapid expansion of the agricultural industry, and of the municipal and industrial sectors. Agricultural developments in SA are affected greatly as the country is facing a current drought crisis as a result of low rainfall and large water demands. With an abundance of saline water globally, desalinisation will be a major contributor to solving the global freshwater crisis. With limited fresh water resources accompanied by the agricultural industry as a major consumer, alternative measures are required to desalinate water specifically for agricultural use. Forward osmosis (FO) is a membrane technology that gained interest over the past decade because it has several advantages over pressure-driven membrane processes such as reverse osmosis (RO). FO technology is based on the natural osmotic process which is driven by a concentration gradient between two solutions separated by a semi-permeable membrane. Naturally, water will permeate through the membrane from a solution of low solute concentration or low osmotic pressure (OP) known as a feed solution (FS) to a solution of a higher concentration or higher OP also known as a draw solution (DS). Whilst various research studies have contributed to several advances in FO, several process limitations such as reverse solute flux (RSF), concentration polarisation (CP) and membrane fouling remain problematic, hindering FO for large-scale applications. Further investigation is therefore warranted and crucial in order to understand how to mitigate these limitations to develop/improve future processes. The aim of this study was to evaluate a fertiliser-drawn forward osmosis (FDFO) system by investigating the effects of membrane orientation, system flow rate, DS concentration, and membrane fouling on an FDFO systems performance and energy consumption. The FS used was synthetic brackish water with a sodium chloride (NaCl) content of 5 g/L whereas a potassium chloride (KCl) synthetic fertiliser was used as a DS. The membrane utilised was a cellulose triacetate (CTA) membrane and was tested in forward osmosis mode (FO mode) and pressure retarded osmosis mode (PRO mode) whilst the system flow rate was adjusted between 100, 200 and 400 mL/min. Additionally, the DS concentration was altered from 0.5, 1 and 2 M KCl, respectively. Experiments were performed using a bench scale FO setup which comprised of an i) FO membrane cell, ii) a double head variable peristaltic pump for transporting FS and DS’s respectively, iii) a digital scale to measure the mass of the DS, iv) a magnetic stirrer to agitate the FS, v) two reservoirs for the FS and DS, respectively, vi) a digital multiparameter meter to determine FS electrical conductivity (EC) and vii) a digital electrical multimeter to measure system energy consumption. Each experiment comprised of seven steps i) pre-FDFO membrane control, ii) membrane cleaning, iii) FDFO experiment, iv) post-FDFO membrane control, v) membrane cleaning, vi) membrane damage dye identification and vii) membrane cleaning. Pre- and post-FDFO membrane control experiments operated for 5 h whilst each membrane cleaning procedure operated for 30 min. The FDFO experiment operated for 24 h whilst the membrane damage dye identification operated until a minimum of 10 mL water was recovered. The process parameter which largely contributed to a beneficial system performance and specific energy consumption (SEC) was the increase in DS concentration. Water fluxes increased approximately threefold from a DS concentration increase from 0.5 to 1 M, followed by an additional 30 to 50 % rise in water flux at a DS concentration increase 1 to 2 M. SEC decreased by 58 and 53 % for FO and PRO modes, respectively, with a DS concentration increase from 0.5 to 1 M. An additional 35 and 37 % SEC reduction for FO and PRO modes was obtained for a DS concentration increase from 1 to 2 M. Altering the membrane from FO to PRO did not contribute to a beneficial system performance nor did it improve SEC. However, at a DS concentration of 0,5 M, the PRO mode obtained a 5.3 % greater water recovery compared to the FO mode. Conversely, at a DS concentration of 1 and 2 M, the FO mode achieved 5.4 and 7.0 % greater water recoveries compared to the PRO mode. The increase in flow rate also did not increase system performance significantly, however, a fluctuation in system SEC was observed. Throughout the study, no membrane fouling was observed, however, possible minute traces of membrane fouling could be observed from the membrane surface electron microscope (SEM) images. Additionally, minor changes in post- FDFO membrane control water recovery results were noticed which support the possible occurrence of membrane fouling during the FDFO experiment.