Impact of Draw Solution Concentration on Forward Osmosis Process: A Simulation Study

In this study, a simulation model was used to evaluate the performance of forward osmosis process. A solution of low salinity was used as the feed solution in forward osmosis to dilute saline solution (i.e. draw solution) for further desalination. The paper evaluated the effect of the draw solution concentration on the recovery rate and energy consumption in forward osmosis. It was found that increasing the concentration of draw solution increased the recovery rate. Also, while increasing concentration of draw solution, energy consumption decreased. The maximum recovery rate of 33% was achieved using (0.5M NaCl) draw solution and a flow rate of 40000 m3/day. The specific power consumption was 0.21 kWh/m3.This research is made possible by Graduate Sponsorship Research Award (GSRA6-1- 0509-19021) from Qatar National Research Fund (QNRF). The statements made herein are solely the responsibility of the authors

Treatment of Wastewater Using Reverse Osmosis for Irrigation Purposes

This work investigates the performance of reverse osmosis (RO) for the reclamation of treated sewage effluent (TSE) to be used as irrigation water for food crops. The feed water used in this study was a real sample of ultra-filtered tertiary treated sewage effluent (TSE). Reverse osmosis (RO) was evaluated using the following experimental conditions applied pressure (10 - 20) bar, flow rate 3.5 LPM and (BW30LE) membrane. The performance of RO was evaluated according to the water flux and rejection of dissolved solids. The final water quality was compared with irrigation water standards. The results reported in this study show that reverse osmosis (RO) is capable of reclaiming treated sewage effluent (TSE) to be used as irrigation water for food crops. The maximum average flux was 77.7 LMH achieved using a feed pressure of 16 bar. The permeate water generated using RO had high quality which met the irrigation standards for food crops.This research is made possible by graduate sponsorship research award (GSRA6-1- 0509-19021) from Qatar National Research Fund (QNRF). The statements made herein are solely the responsibility of the authors

Empirical evaluation of drivers’ start-up behavior at signalized intersection using driving simulator

Start-up behavior at signalized intersection mainly depends on perception reaction time of drivers to the green phase. This study investigated the start-up behavior at signalized intersections by considering reaction time, acceleration and jerk (the rate of change of acceleration) of drivers in the state of Qatar. Distributions for reaction time, acceleration and jerk were plotted and the mean and 50th percentile values were presented. Three demographic factors (i.e., gender, ethnicity and age) were analyzed using two-tailed/unpaired t-tests. The relationships between acceleration and reaction time, and jerk and reaction time were investigated by linear regression analyses. Descriptive analysis showed that drivers had a mean reaction time of 2.91 s. Furthermore, Arab drivers had significantly lower reaction time than non-Arab drivers. Regarding the jerk maneuvers, young drivers (below 30 years) displayed significantly higher jerk than drivers of 30 years or above. Results from linear regressions showed significant negative correlations in both models (i.e., reaction time on acceleration, reaction time on jerk). As this study targeted multi-cultural drivers’ population, the results of reaction time and jerk distributions could be used as inputs in simulation models which are developed for evaluating driver behavior and safety at signalized intersections in regions with multi-cultural driving population

Fabrication of Fouling Resistant Ti3C2Tx(MXene) Cellulose Acetate Nanocomposite Membrane for Forward Osmosis Application

Forward Osmosis (FO) is one of the promising technologies that can be used to combat growing water scarcity. However, FO membrane fouling hinders the widespread application of this technology by significantly reducing the water flux and membrane lifecycle. Although forward osmosis has shown lower membrane fouling when compared to other membrane technologies, forward osmosis membrane resistance to fouling must still be improved. In this study, Ti3C2Tx (MXene) was used to improve the fouling resistance of FO flat-thin film membranes. The mixed-matrix Ti3C2Tx (MXene)/ cellulose acetate (CA) membranes with different (wt%) loading of MXene were fabricated by covalent crosslinking followed by phase inversion method. The fabricated membranes were characterized by X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), contact angle measurement and scanning electron microscopy (SEM). The performance of the fabricated FO membranes was evaluated utilizing seawater as draw solution (DS) and two feed solutions (FS) namely; distilled water (DI) and treated sewage effluent (TSE). The water flux, reverse solute flux and the rejection of dissolved solids were evaluated in the FO process. It was observed that the cross-linked cellulose acetate membrane with 8 wt% MXene (CCAM-8%) showed higher resistance to fouling when compared with commercial thin-filmcomposite (TFC) FO membrane, the water flux of CCAM-8% decreased by only 10.7% using TSE as FS compared to DI, where the water flux of the TFC commercial membrane decreased by 32.2% when using TSE as FS compared to DI

Effects of current, electrodes spacing and operational time on the removal of heavy metals from primary treated municipal wastewater using dielectrophoresis.

Electrocoagulation (EC) is an emerging technology that has been used to treat heavy metals from different kinds of wastewater. This paper discusses the effects of inducing Dielectrophoretic (DEP) force in EC system for the treatment of heavy metals from primary treated municipal wastewater. In order to achieve the optimum run of DEP, COMSOL software was used to identify the highest force that can be obtained by changing electrodes spacing and applied current. As per the results obtained from experiments and numerical methods, the optimum run was at operational time of 30 min, electrodes spacing of 0.5 cm and applied current of 600 mA (17.14 mA/cm2 current density). In both process aluminium electrodes were used and they were connected to alternative current (AC) power supply. The efficiency of AC-DEP was found to be better than AC-EC. The removal efficiencies of Fe and Mn using AC-DEP were 80.6% and 29.7% respectively, while AC-EC removed 78.23% of Fe and 28.8% of Mn. Moreover, the increase in the aluminium content using AC-DEP and AC-EC was 810.3% and 1330.8% respectively. Furthermore, the energy consumption of AC-DEP was 4.9 kWh/m3 while AC-EC consumed 5kWh/m3

Evaluation of ultrafiltration and multimedia filtration as pretreatmeprocess for forward osmosis

In order to reduce scaling in a multistage flash (MSF) desalination plant, the brine reject can be diluted using forward osmosis (FO) before recycling. In this FO process, the brine is used as the draw solution (DS) and seawater is used as the feed solution (FS). However, the FO process suffers from low water flux owing to membrane fouling. The water flux in FO can be enhanced by reduc-ing the foulant concentration in the FO feed solution (FS). Thus, in this paper seawater, multimedia sand filtered seawater, and ultrafiltrated seawater is being used as feed solution for the FO process. The flowrate of the feed solution was kept constant at 2.0 L/min. However, the flowrate of the draw solution (DS) were tested at 2.0 and 0.8 L/min. When the flowrate of the DS was 0.8 L/min, the highest initial flux of 44.1 L/m2 h were obtained using ultrafiltrated seawater as FS. After the initial run, the membrane was cleaned and during the second run, 83% of the initial flux was recovered using the ultrafiltrated seawater as FS. For ultrafiltrated seawater, the water recovery rate and specific energy consumption was 36.2% and 0.065 kWh/m3, respectively. 2020 Desalination Publications. All rights reserved.This research is made possible by NPRP award (NPRP10-0117-170176) from the Qatar National Research Fund (QNRF). The statements made herein are solely the responsibility of the authors. In addition, the authors wish to thank Qatar Foundation for the financial support pro-vided to one of the co-authors through a graduate sponsorship research award (GSRA6-1-0509-19021). The authors also wish to thank Qatar Electricity and Water Company (QEWC) for the supply of brine. Also, the authors would like to thank the Central Laboratories Unit (CLU) at Qatar University for generating the SEM images.Scopu

Comparison of nanofiltration with reverse osmosis in reclaiming tertiary treated municipal wastewater for irrigation purposes

This study compares the performance of nanofiltration (NF) and reverse osmosis (RO) for the reclamation of ultrafiltered municipal wastewater for irrigation of food crops. RO and NF technologies were evaluated at different applied pressures; the performance of each technology was evaluated in terms of water flux, recovery rate, specific energy consumption and quality of permeate. It was found that the permeate from the reverse osmosis (RO) process complied with Food and Agriculture Organization (FAO) standards at pressures applied between 10 and 18 bar. At an applied pressure of 20 bar, the permeate quality did not comply with irrigation water standards in terms of chloride, sodium and calcium concentration. It was found that nanofiltration process was not suitable for the reclamation of wastewater as the concentration of chloride, sodium and calcium exceeded the allowable limits at all applied pressures. In the reverse osmosis process, the highest recovery rate was 36%, which was achieved at a pressure of 16 bar. The specific energy consumption at this applied pressure was 0.56 kWh/m3. The lowest specific energy of 0.46 kWh/m3 was achieved at an applied pressure of 12 bar with a water recovery rate of 32.7%.This research was funded by Qatar National Research Fund (QNRF) graduate sponsorship research award (GSRA6-1-0509-19021). This research was made possible by an Award (GSRA6-1-0509-19021) from Qatar National Research Fund (a member of Qatar Foundation). We would also like to thank Central Laboratories Unit (CLU) at Qatar University for generating SEM images and the ion chromatography tests. The contents herein are solely the responsibility of the authors.Scopu

Unlocking the application potential of electrocoagulation process through hybrid processes

Electrocoagulation (EC) has attracted attention during the recent years due to its ease of use and high removal rate of organic and inorganic pollutants. It was found that using EC as a pretreatment process can decrease the overall energy consumption and improve the treated water quality. This literature review evaluates the efficiency of integrating EC process with other water treatment processes including membranes, chemical, electromagnetic and oxidation processes. The studied technologies were ultrafiltration (EC-UF), reverse osmosis (EC-RO), forward osmosis (EC-FO), membrane distillation (EC-MD), forward osmosis-membrane distillation (EC-FO-MD), membrane bioreactor (EC-MBR), electrodialysis (EC-ED), ozonation (EC-O3), ultraviolet (EC-UVC/VUV), peroxi-electrocoagulation (EC-H2O2), activated carbon adsorption (EC-AC), biofiltration (EC-BF) and electro-oxidation (EC-EO). The overall performance was evaluated using pollutants removal efficiency, energy consumption and operational cost. Then, the performance of pilot scale hybrid electrocoagulation processes and the current status of implementation was discussed. The future potential of electrocoagulation lies with proper hybridization of EC with other water treatment processes that would minimize the overall cost and enhance quality of the treated water. 2021 Elsevier LtdThis research is made possible by graduate sponsorship research award (GSRA5-2-0525-18072) and ( GSRA6-1-0509-19021) from Qatar National Research Fund (QNRF) (a member of Qatar Foundation) . The statements made herein are solely the responsibility of the authors.Scopu

A hybrid nf-fo-ro process for the supply of irrigation water from treated wastewater: Simulation study

Municipal treated wastewater could be considered as a water source for food crop irrigation purposes. Enhancing the quality of treated wastewater to meet irrigation standards has become a necessary practice. Nanofiltration (NF) was used in the first stage to produce permeate at relatively low energy consumption. In the second stage, two membrane combinations were tested for additional water extraction from the brine generated by the NF process. The simulation results showed that using a hybrid forward osmosis (FO)-reverse osmosis (RO) system is more efficient than using the RO process alone for the further extraction of water from the brine generated by the NF process. The total specific energy consumption can be reduced by 27% after using FO as an intermediate process between NF and RO. In addition, the final permeate water quality produced using the hybrid FO-RO system was within the allowable standards for food crops irrigation. 2021 by the authors. Licensee MDPI, Basel, Switzerland.Acknowledgments: This research was made possible by an Award (GSRA6-1-0509-19021) from Qatar National Research Fund (a member of Qatar Foundation).Scopu

A Hybrid NF-FO-RO Process for the Supply of Irrigation Water from Treated Wastewater: Simulation Study

Municipal treated wastewater could be considered as a water source for food crop irrigation purposes. Enhancing the quality of treated wastewater to meet irrigation standards has become a necessary practice. Nanofiltration (NF) was used in the first stage to produce permeate at relatively low energy consumption. In the second stage, two membrane combinations were tested for additional water extraction from the brine generated by the NF process. The simulation results showed that using a hybrid forward osmosis (FO)–reverse osmosis (RO) system is more efficient than using the RO process alone for the further extraction of water from the brine generated by the NF process. The total specific energy consumption can be reduced by 27% after using FO as an intermediate process between NF and RO. In addition, the final permeate water quality produced using the hybrid FO-RO system was within the allowable standards for food crops irrigation