Application of ultra low pressure reverse osmosis (ULPRO) membrane to water and wastewater

2000 ◽  
Vol 42 (12) ◽  
pp. 123-135 ◽  
Author(s):  
H. Ozaki ◽  
K. Sharma ◽  
W. Saktaywin ◽  
D. Wang ◽  
Y. Yu

There is a worldwide grave concern about water pollution control. To mitigate the water scarcity, in arid zones and in the areas with no other sources but brackish water, reverse osmosis technology has played an important role. In an effort to reduce the cost of energy requirement for RO operation, nanofiltration has been developed. Until recently the nanofiltration has been used in water softening and removal of disinfection byproduct (DBO). Use of nanofiltration to desalinate brackish water has been ruled out due to low rejection of salts. The introduction of ultra-low pressure reverse osmosis membrane, categorically a nanofiltration, has widened the horizon of using the nanofiltration in desalinating brackish water as well as surfacewater and wastewater. This development ensures the increase in flux due to improvement in active surface layer formation with the application of very small pressure. The surface charge and hydrophilicity on the surface material of the membrane have shown better flux stability in the high fouling conditions. With the addition of higher flux and higher rejection based on the same chemistry, ULPRO has made another step forward. This introduction will certainly reduce the operation cost and, more importantly, improve the overall reliability of the RO system. Application of nanofiltration is broadened to surface water treatment, wastewaters for nutrient removal and heavy metal rejection from wastewater.

2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Abdul Rahman Hassan ◽  
Al Dabbaas Khuzama Mansoor A ◽  
Nor Azirah Sulaiman ◽  
Nurul Hannan Mohd Safari ◽  
Sabariah Rozali

Water shortage has become a real problem at global level and therefore, new and innovative technologies were established to provide sustainable solutions to water crisis. One of the effective approaches to resolve the global challenges is introducing the membrane-based desalination. Reverse Osmosis (RO) is a pressure driven membrane process which becoming increasingly popular and widely used for water purification applications that require high salt rejection such as brackish and seawater desalination. In this study, the influence of Sodium dodecyl sulphate (SDS) surfactant in producing the finest membrane for desalination were investigated in terms of performance, morphological structure and molecular orientation. From a polymer blending of polysulfone (PSF)/N-Methyl-2-Pyrrolidone (NMP)/polyvinylpyrrolidone (PVP)/sodium dodecyl sulphate (SDS) were formulated for making of low pressure reverse osmosis (LPRO) membrane. In order to examine the influence of SDS surfactant, different concentration from 0 wt% to 3 wt% were employed for desalination application of 10,000ppm (brackish water) and 50 000ppm (seawater). Experimental data showed that the increasing of 0.5wt% in surfactant produced higher pure water permeation (PWP) and flux. At 2.5wt% of SDS, the LPRO membranes showed the highest PWP of about 44.8L/m2h and brackish water flux at 45.58L/m2h. Meanwhile, at 3.0wt%, the highest flux of seawater at 39.37L/m2h was obtained. Moreover, the optimized LPRO (2wt% of SDS) membrane performed high rejection ratio of 90.9% for brackish water and 90.4% for seawater concentration of 10,000ppm and 50,000ppm, respectively. Therefore, the findings revealed that the fabricated LPRO membrane having a good potential to be used as eco-efficient desalination process of brackish water and seawater technology.


Author(s):  
Karim Hamza ◽  
Mohammed Shalaby ◽  
Ashraf O. Nassef ◽  
Mohamed F. Aly ◽  
Kazuhiro Saitou

This paper explores optimal design of reverse osmosis (RO) systems for water desalination. In these systems, salty water flows at high pressure through vessels containing semi-permeable membrane modules. The membranes can allow water to flow through, but prohibit the passage of salt ions. When the pressure is sufficiently high, water molecules will flow through the membranes leaving the salt ions behind, and are collected in a fresh water stream. Typical system design variables include the number and layout of the vessels and membrane modules, as well as the operating pressure and flow rate. This paper presents models for single and two-stage pressure vessel configurations. The models are used to explore the various design scenarios in order to minimize the cost and energy required per unit volume of produced fresh water. Multi-objective genetic algorithm (GA) is used to generate the Pareto-optimal design scenarios for the systems. Case studies are considered for four different water salinity concentration levels. Results of the studies indicate that even though the energy required to drive the RO system is a major contributor to the cost of fresh water production, there exists a tradeoff between minimum energy and minimum cost. An additional parametric study on the unit cost of energy is performed in order to explore future trends. The parametric study demonstrates how an increase in the unit cost of energy may shift the minimum cost designs to shift to more energy-efficient design scenarios.


Desalination ◽  
1977 ◽  
Vol 22 (1-3) ◽  
pp. 311-333 ◽  
Author(s):  
Robert L. Goldsmith ◽  
Barry A. Wechsler ◽  
Shigeyoshi Hara ◽  
Koh Mori ◽  
Yutaka Taketani

Desalination ◽  
1986 ◽  
Vol 58 (1) ◽  
pp. 55-67 ◽  
Author(s):  
P. Glueckstern ◽  
Y. Kantor ◽  
S. Kremen ◽  
M. Wilf

Author(s):  
Saffa Syamimi Norizam ◽  
Mohd Azlan Hussain ◽  
Mohd Usman Mohd Junaidi

Abstract Water purification from brackish water sources has been acknowledged as one of the most promising ways in producing drinkable water in water-scarce areas. In this study, an ultra-low pressure reverse osmosis (ULPRO) membrane was numerically and experimentally investigated to produce drinking water by the removal of sodium chloride salt which provides further validation of the model from a practical perspective. An enhanced predictive model based on Donnan-Steric Pore Model with dielectric exclusion (DSPM-DE) incorporating the osmotic effects was formulated in process simulation. The feed pressure and concentration were optimized as input variables and interaction between them was observed, while salt rejection and water recovery rate were taken as response attributes. The results obtained on the ULPRO membrane showed that the performance depends on the charge, steric, and dielectric effects. Furthermore, the enhanced model was validated with the experimental data attained from a lab-scale filtration system with good accuracy in the salt rejection and water recovery results. Comparing the enhanced DSPM-DE with the existing solution diffusion model reveals that the enhanced model predicts the membrane performance better and thereby qualifies itself as a reliable model for desalination of brackish water using ULPRO membrane.


2015 ◽  
Vol 9 (1) ◽  
pp. 2303-2310
Author(s):  
Abderrahim Benchaib ◽  
Abdesselam Mdaa ◽  
Izeddine Zorkani ◽  
Anouar Jorio

The vanadium dioxide VO₂ currently became very motivating for the nanotechnologies’ researchers. It makes party of the intelligent materials because these optical properties abruptly change semiconductor state with metal at a critical  temperature θ = 68°C. This transition from reversible phase is carried out from a monoclinical structure characterizing its semiconductor state at low temperature towards the metal state of this material which becomes tétragonal rutile for  θ ˃ 68°C ; it is done during a few nanoseconds. Several studies were made on this material in a massive state and a thin layer. We will simulate by Maple the constant optics of a thin layer of VO₂ thickness z = 82 nm for the metal state according to the energy ω of the incidental photons in the energy interval: 0.001242 ≤ ω(ev) ≤ 6, from the infra-red (I.R) to the ultra-violet (U.V) so as to be able to control the various technological nano applications, like the detectors I.R or the U.V,  the intelligent windows to  increase  the energy efficiency in the buildings in order to save the cost of energy consumption by electric air-conditioning and the paintings containing nano crystals of this material. The constant optics, which we will simulate, is: the index of refraction, the reflectivity, the transmittivity, the coefficient of extinction, the dielectric functions ԑ₁ real part and  ԑ₂  imaginary part of the permittivity complexes ԑ of this material and the coefficient absorption. 


Author(s):  
Leonid S. Bobe ◽  
Nikolay A. Salnikov

Analysis and calculation have been conducted of the process of low-pressure reverse osmosis in the membrane apparatus of the system for recycling hygiene water for the space station. The paper describes the physics of the reverse osmosis treatment and determines the motive force of the process, which is the difference of effective pressures (operating pressure minus osmotic pressure) in the solution near the surface of the membrane and in the purified water. It is demonstrated that the membrane scrubbing action is accompanied by diffusion outflow of the cleaning agent components away from the membrane. The mass transfer coefficient and the difference of concentrations (and, accordingly, the difference of osmotic pressures) in the boundary layer of the pressure channel can be determined using an extended analogy between mass transfer and heat transfer. A procedure has been proposed and proven in an experiment for calculating the throughput of a reverse osmosis apparatus purifying the hygiene water obtained through the use of a cleaning agent used in sanitation and housekeeping procedures on Earth. Key words: life support system, hygiene water, water processing, low-pressure reverse osmosis, space station.


Sign in / Sign up

Export Citation Format

Share Document