“…Here, unlike RO, there is a substantial concentration gradient at the support medium. Figure 1 Schematic concentration profile depicted for OARO membranes 44 . …”
Microbial electrosynthesis (MES), is an emerging technology, for sustainable wastewater treatment. The dilute acetate solution, produced via MES, must be recovered, as dilute solutions can be expensive to store and transport. The acetate is expensive and environmentally damaging to recover by heat-intensive evaporative methods, such as distillation. In pursuit of a better energy economy, a membrane separation system is simulated to raise the concentration from 1 to 30 wt%, at a hydraulic pressure of approximately 50 bar. The concentrate is then simulated to be heat dried. Reverse osmosis (RO) could rase the acetate concentration to 8 wt%. A novel adaptation of osmotically assisted reverse osmosis (OARO) is then simulated to increase the concentration from 8 to 30 wt%. The inclusion of OARO, rather than a standalone RO unit, reduces the total heat and electric power requirement by a factor of 4.3. It adds to the membrane area requirement by a factor of 6. The OARO simulations are conducted by the internal concentration polarisation (ICP) model. Before the model is used, it is fitted to OARO experimental data, obtained from the literature. Membrane structure number of 701 µm and permeability coefficient of 2.51 L/m2/h/bar are ascertained from this model fitting exercise.
“…Here, unlike RO, there is a substantial concentration gradient at the support medium. Figure 1 Schematic concentration profile depicted for OARO membranes 44 . …”
Microbial electrosynthesis (MES), is an emerging technology, for sustainable wastewater treatment. The dilute acetate solution, produced via MES, must be recovered, as dilute solutions can be expensive to store and transport. The acetate is expensive and environmentally damaging to recover by heat-intensive evaporative methods, such as distillation. In pursuit of a better energy economy, a membrane separation system is simulated to raise the concentration from 1 to 30 wt%, at a hydraulic pressure of approximately 50 bar. The concentrate is then simulated to be heat dried. Reverse osmosis (RO) could rase the acetate concentration to 8 wt%. A novel adaptation of osmotically assisted reverse osmosis (OARO) is then simulated to increase the concentration from 8 to 30 wt%. The inclusion of OARO, rather than a standalone RO unit, reduces the total heat and electric power requirement by a factor of 4.3. It adds to the membrane area requirement by a factor of 6. The OARO simulations are conducted by the internal concentration polarisation (ICP) model. Before the model is used, it is fitted to OARO experimental data, obtained from the literature. Membrane structure number of 701 µm and permeability coefficient of 2.51 L/m2/h/bar are ascertained from this model fitting exercise.
“…OARO has the advantages of high water recovery and low reverse solute diffusion. [9][10][11][12][13] Thus, to put OARO into practical use, it is necessary to investigate the scale-up process and assess its feasibility. There are several pilot scale membrane module types that can operate with different membrane structures and filling methods.…”
Section: Introductionmentioning
confidence: 99%
“…Very recently, osmotically assisted reverse osmosis (OARO) was proposed as a new concentration technique. − The OARO process, which is schematically illustrated in Figure , is also known as draw solution-assisted reverse osmosis (DSARO), osmotically enhanced dewatering-reverse osmosis (OED-RO), or cascading osmotically mediated reverse osmosis (COMRO) . In this process, it is important to supply solutions of equal concentration on each side of the semipermeable membrane.…”
Section: Introductionmentioning
confidence: 99%
“…Furthermore, there is no need for high-pressure-resistant material for pipes and modules, and reductions in equipment costs can be expected. OARO has the advantages of high water recovery and low reverse solute diffusion. − Thus, to put OARO into practical use, it is necessary to investigate the scale-up process and assess its feasibility. There are several pilot-scale membrane module types that can operate with different membrane structures and filling methods.…”
Solution concentration processes such as evaporation, freeze concentration, and reverse osmosis are commonly used in food processing and environmental applications. However, these processes are frequently examined to lower energy costs and improve concentration ratios. This study performed concentration tests and theoretical calculations for osmotically assisted reverse osmosis (OARO) using a pilot scale hollow fiber membrane module. In the concentration test using NaCl solution, water flux and concentration ratio were measured with changing flow rate, concentration, and applied pressure. Water permeation and solution concentration were achieved, even using concentrated salt solutions (0.5 and 1.0 M), with applied pressure of 8-12 bar, which was lower than the osmotic pressure (25 bar for 0.5 M NaCl; 50 bar for 1.0 M NaCl). The calculation results were in good agreement with the experimental results and the validity of the calculation model was confirmed. Analysis revealed that the concentration gradient and concentration polarization in the module changed with operating conditions and these factors affected the water flux and the concentration ratio.
“…The famous technology of electrolysis and membrane filtration such as electrodialysis, microbial electrolysis, reverse osmosis (RO), membrane distillation (MD), forward osmosis (FO), microfiltration (MF) ultrafiltration (UF) and nanofiltration (NF) could not be denied in removing salt [10]- [19], [20]. However, the amount of capital, maintenance and operating costs are very expensive [21]- [23]. The higher the salinity, the higher the membrane maintenance [24].…”
Groundwater resources are one of the major sources of drinking water and cleaning agent around the world. In European countries, such as Denmark, Austria, Belgium, Hungary, Romania and Iceland, more than 70% of their water supply comes from underground reservoirs [1], [2]. In the United States, groundwater is used to supply potable water for more than 96% of its inhabitants in rural areas [3]. In Asia, groundwater is also widely used for their water supply for example 80% in India's interior, 80% in the Maldives and more than 60% of water supply in the Philippines and Nepal comes from groundwater sources [3]. On the other hand, groundwater in Malaysia accounts for more than 90% of the country's water resources and is spatially distributed all over the country [4]. Kura et al. [4] reported that over the last three decades, there has been an increase in freshwater demand due to Malaysia's great economic and infrastructure development. According to, Manap et al. [5], it is estimated that the groundwater demand in Malaysia has been rising by 63% from 2000 to 2050 particularly as an alternative water sources in urban areas. However, the presence of salinity is inevitable when the water table in groundwater mixes with seawater. Salinity is defined as the concentration of salts in water or soil. It is classified in 3 forms and causes i.e. primary, secondary and tertiary salinity [6]. Primary salinity is called natural salinity. It is caused by natural processes such as from weathering of rocks and salt accumulation in the rainfall for thousands of years. Therefore, the small amount of salt in soil and water can be transferred to streams, rivers and groundwater. Secondary salinity is called dryland salinity where the accumulation of primary salinity brings salt to the surface through increased groundwater level. The discharging saline from groundwater can saturate the area with saline and leave salt crystals during dry season. This area is called salt
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