M.A. Al-Obaidi

Steady State and Dynamic Modeling of Spiral Wound Wastewater Reverse Osmosis Process

Abstract Reverse osmosis (RO) is one of the most important technologies used in wastewater treatment plants due to high contaminant rejection and low utilization of energy in comparison to other treatment procedures. For single-component spiral-wound reverse osmosis membrane process, one dimensional steady state and dynamic mathematical models have been developed based on the solution-diffusion model coupled with the concentration polarization mechanism. The model has been validated against reported data for wastewater treatment from literature at steady state conditions. Detailed simulation using the dynamic model has been carried out in order to gain deeper insight of the process. The effect of feed flow rate, pressure, temperature and concentration of pollutants on the performance of the process measured in terms of salt rejection, recovery ratio and permeate flux has been investigated.

Scope and limitations of the irreversible thermodynamics and the solution diffusion models for the separation of binary and multi-component systems in reverse osmosis process

Abstract Reverse osmosis process is used in many industrial applications ranging from solute-solvent to solvent–solvent and gaseous separation. A number of theoretical models have been developed to describe the separation and fluxes of solvent and solute in such processes. This paper looks into the scope and limitations of two main models (the irreversible thermodynamics and the solution diffusion models) used in the past by several researchers for solute-solvent feed separation. Despite the investigation of other complex models, the simple concepts of these models accelerate the feasibility of the implementation of reverse osmosis for different types of systems and variety of industries. Briefly, an extensive review of these mathematical models is conducted by collecting more than 70 examples from literature in this study. In addition, this review has covered the improvement of such models to make them compatible with multi-component systems with consideration of concentration polarization and solvent-solute-membrane interaction.

Optimisation of membrane design parameters of a spiral-wound reverse osmosis module for high rejection of dimethylphenol from wastewater at low energy consumption

Abstract Dimethylphenol is a very toxic pollutant found in wastewater, where its low concentration can hinder the usage of reused water in various industrial applications. Therefore, the removal of this compound from industrial effluents is critical for the safe discharge into surface water. In this research, a simple model based on the solution-diffusion principles is developed and validated using experimental data. The model is then used to simulate a wastewater treatment process using a spiral-wound RO module and assess the impact of membrane design parameters including; membrane length and width, feed channel height on the rejection of dimethylphenol and energy consumption of the process. Finally, the membrane design parameters are optimised within a multi-objective optimisation framework to simultaneously maximise the dimethylphenol rejection and at the same time minimise the energy consumption.

Modeling the Performance of Low Pressure Reverse Osmosis Membrane System for N-nitrosamine Rejection

Abstract In this work, a one-dimensional model of a low-pressure reverse osmosis (LPRO) membrane process has been developed using an augmented model previously developed by the same authors to analyse the rejection of N-nitrosamine from wastewater. The model, based on the principles of the solution-diffusion coupled with the concentration polarization theory, is validated using experimental data of N-nitrosamine rejection from the literature for three different types of membranes in an RO process. Finally, detailed simulation of the LPRO process is carried out for variety of operating conditions such as inlet feed flow rate, pressure, feed concentration, and temperature.

Optimal Reverse Osmosis Network Configuration for the Rejection of Dimethylphenol from Wastewater

AbstractReverse osmosis (RO) has long been recognized as an efficient separation method for treating and removing harmful pollutants such as dimethylphenol in wastewater treatment. This paper studi...

Significant energy savings by optimising membrane design in the multi-stage reverse osmosis wastewater treatment process

The total energy consumption of many reverse osmosis (RO) plants has continuously improved as a result of manufacturing highly impermeable membranes in addition to implementing energy recovery devices. The total energy consumption of the RO process contributes significantly to the total cost of water treatment. Therefore, any way of keeping the energy consumption to a minimum is highly desirable but continues to be a real challenge in practice. Potential areas to explore for achieving this include the possibility of optimising the module design parameters and/or the associated operating parameters. This research focuses on this precise aim by evaluating the impact of the design characteristics of membrane length, width, and feed channel height on the total energy consumption for two selected pilot-plant RO process configurations for the removal of chlorophenol from wastewater. The proposed two configurations, with and without an energy recovery device (ERD), consist of four cylindrical pressure vessels connected in series and stuffed with spiral wound membranes. A detailed steady-state model developed earlier by the authors is used here to study such an impact via repetitive simulation. The results achieved confirm that the overall energy consumption can be reduced by actually increasing the membrane width with a simultaneous reduction of membrane length at constant membrane area and module volume. Energy savings of more than 60% and 54% have been achieved for the two configurations with and without an ERD respectively using process optimization. The energy savings are significantly higher compared to those of other available similar studies from the literature.

Performance evaluation of multi-stage reverse osmosis process with permeate and retentate recycling strategy for the removal of chlorophenol from wastewater

Abstract Reverse osmosis (RO) is one of the most widely used technologies for wastewater treatment for the removal of toxic impurities, such as phenol and phenolic compounds from industrial effluents. In this research, performance of multi-stage RO wastewater treatment system is evaluated for the removal of chlorophenol from wastewater using model-based techniques. A number of alternative configurations with recycling of permeate, retentate, and permeate-retentate streams are considered. The performance is measured in terms of total recovery rate, permeate product concentration, overall chlorophenol rejection and energy consumption and the effect of a number of operating parameters on the overall performance of the alternative configurations are evaluated. The results clearly show that the permeate recycling scheme at fixed plant feed flow rate can remarkably improve the final chlorophenol concentration of the product despite a reduction in the total recovery rate.

Simulation of hybrid trickle bed reactor-reverse osmosis process for the removal of phenol from wastewater

Abstract Phenol and phenolic derivatives found in different industrial effluents are highly toxic and extremely harmful to human and the aquatic ecosystem. In the past, trickle bed reactor (TBR), reverse osmosis (RO) and other processes have been used to remove phenol from wastewater. However, each of these technologies has limitations in terms of the phenol concentration in the feed water and the efficiency of phenol rejection rate. In this work, an integrated hybrid TBR–RO process for removing high concentration phenol from wastewater is suggested and model-based simulation of the process is presented to evaluate the performance of the process. The models for both TBR and RO processes were independently validated against experimental data from the literature before coupling together to make the hybrid process. The results clearly show that the combined process significantly improves the rejection rate of phenol compared to that obtained via the individual processes.