However, high pressures (100-1000 psi) are required to operate RO and NF membranes. Conversely, UF and MF membranes require much lower pressure (5-60 psi). Unfortunately, they are not effective at retaining dissolved ions and organic solutes.
What are the four major pressure-driven membrane processes?
RO and NF are very effective at removing dissolved ions and organic solutes. However, high pressures (100-1000 psi) are required to operate RO and NF membranes. Conversely, UF and MF membranes require much lower pressure (5-60 psi). Unfortunately, they are not effective at …
What are the different types of membranes in water treatment?
In many situations membrane technology can provide solutions to water treatment problems. Increasingly stringent regulations for drinking and waste waters, deterioration of water …
What is a pressure-driven membrane?
Membrane foul- ing causes a loss of water production (flux), reduced permeate quality, and increased trans-membrane pressure drop. Membrane fouling is typically caused by …
What is a membrane process?
Apr 30, 2020 · 2.1. Pressure Driven Membrane Processes. Pressure driven membrane processes are by far the most widely applied membrane processes in wastewater treatment, from …
What are pressure-driven membrane processes?
How do you calculate transmembrane pressure?
What is transmembrane pressure in RO?
What is low pressure membrane filtration?
What is TMP pressure?
What is TMP formula?
What is flux rate in membrane?
What is TMP in dialysis?
What is TMP in UF?
Which type of filtration used pressure for the process?
What is pressure-driven filtration?
Which of the following is a pressure-driven membrane separation process?
What is membrane filtration?
This technique is used in a wide range of applications ranging from dairy processing to wastewater treatment. The semi-permeable membrane acts as a barrier which retains larger particles, while allowing smaller molecules to pass through the membrane into the permeate.
What is a microfiltration membrane?
Microfiltration membranes have pore sizes ranging from 0.1 to 10 µm. They are mainly used for the removal of large particulates, colloids, and bacteria from feed streams. This is especially popular in the food & beverage industry for treating wastewater before discharging it to a municipal sewer.
What is reverse osmosis membrane?
Reverse osmosis membranes are even tighter than nanofiltration membranes, and are able to reject all monovalent ions while allowing water molecules to pass through in aqueous solutions. They can also remove viruses and bacteria found in feed solutions. Common applications for reverse osmosis filtration include seawater desalination and industrial water treatment. It is important to note that since the operating pressure for RO and NF is much higher than the pressure applied by MF and UF, the overall yield is relatively lower than that of MF and UF membranes.
What is membrane process?
Membrane Processes in Treatment of Drinking Water. The membrane processes have been in use for industrial or pharmaceutical applications, and now being applied to the treatment of drinking water. These do not provide residual disinfection hence a need to add small amount of persistent disinfectant like chlorine as a preservative during distribution.
What happens when two solutions are separated by a semipermeable membrane?
a membrane that allows the passage of the solvent but not of the solute), The solvent will naturally pass from the lower-concentration solution to the higher-concentration solution. This process is known as osmosis. It is possible, however, to force the flow ...
What is nano filtration?
Nano – filtration: Uses a membrane with properties between that of RO and ultrafiltration. It allows monovalent ions such as sodium and potassium to pass but. Reject most of divalent ions such as calcium and magnesium and high molecular weight organics.
What is reverse osmosis?
Principle: If two solutions are separated by a semipermeable membrane (i.e. a membrane that allows the passage of the solvent but not of the solute), The solvent will naturally pass from the lower-concentration solution to the higher-concentration solution. This process is known as osmosis.
Abstract
In many situations membrane technology can provide solutions to water treatment problems. Increasingly stringent regulations for drinking and waste waters, deterioration of water resources, emphasis on water for reuse have made membrane processes more viable as treatment processes.
Keywords
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Bibliography
This paper contains extracts of the following publications Google Scholar
How does osmosis work?
Osmosis is the flow of solvent through a semi-permeable membrane, from a di lute solution to a concentrated solution. This flow results from the driving force created by the difference in pressure between the two soluti ons. Osmotic pressure is the pressure that must be added to the concentrated solution side in o rder to stop the solvent flow through the membrane. Reverse osmosis is the process of rev ersing the flow, forcing water through a membrane from a concentrated solution to a dilute solution to produce filtered water.
How does EDR work?
This reversal stops the buildup of concentrated solutions on the membrane and thereby reduces the accumulation of inorganic and organic deposition on the membrane surface. EDR systems are similar to ED systems, designed with adequate chamber area to collect both product water and brine. EDR produces water of the same quality as ED.
Why are membrane processes important?
Membrane processes are an interesting alternative for water treatment because these are compact and they require low energy consumption and low or no chemical load. However, the performance of membrane processes are sensitive to water conditions and the operation deteriorates with time.
What is membrane process?
Membrane processes are advanced filtration processes that utilize the separation properties of finely porous polymeric or inorganic films. Membrane separations are used in a wide range of industrial processes to separate biological macromolecules, colloids, ions, solvents, and gases. To design, develop, and model membrane processes, ...
What is membrane separation?
Membrane separations are used in a wide range of industrial processes to separate biological macromolecules, colloids, ions, solvents, and gases. To design, develop, and model membrane processes, knowledge of the physical properties of the solution to be separated is paramount. These properties influence the choice of membrane ...
What is the advantage of microfiltration?
Microfiltration membrane processes provides numerous advantages for various industrial applications, such as they are economical, effective, and efficient. Among different industrial applications an important membrane process application is oily-wastewater treatment. Microfiltration membrane process due to its ability to process low feed concentrations is promising for this application, because the typical oily-wastewater composition varies from 50 mg/L to 1000 mg/L of oil. The highly efficient microfiltration membrane process helps in achieving separation efficiency of almost 90%–99% even with low oil concentrations.
What was the initial phase of the pilot trials?
The initial phase of the pilot trials involved operating the membrane modules without chemical pre-treatment. Samples were routinely taken from the raw water and permeate sample locations and analyzed for the water quality parameters outlined in Table 3.
What is the purpose of this case study?
The objective of this case study is to help undergraduate students apply engineering theory to the principles and scope of designing membrane systems for drinking water treatment. The case study outlines the activities of an engineering consulting firm that has been contracted to submit a preliminary design for a new water treatment plant for a rural community in Nova Scotia, Canada. The design is required to replace existing 20-year old facility and concur with new treatment standards for municipal surface source water treatment facilities established by the regulator. Preliminary analysis of water samples shows a source water that has low alkalinity, elevated color from naturally occurring matter (NOM) and seasonal spikes of turbidity and manganese. Additional challenges associated with this project include adapting the final design into the current infrastructure in terms of operational, maintenance and footprint constraints. This case presents the treatment capabilities of the existing treatment train as compared to a proposed design based on membrane filtration. Specifically, a review of the results of pilot-scale membrane trials leads the reader to critically examine the viability of membrane technology for small-scale water treatment applications within the context of meeting new drinking water standards.
Can a case study be discussed in class?
The case study can be discussed by the instructor as an in-class example, however may be best suited for in-class group exercise or administered as a group or individual student assignment.
What is membrane water treatment?
Membranes are used in water treatment to separate contaminants from water based on properties such as size or charge. Common membrane processes include microfiltration, ultrafiltration, nanofiltration, reverse osmosis, and electrodialysis.
Is seawater desalination renewable?
As worldwide fresh water supplies become increasingly stressed and world populations continue to grow, seawater desalination has become an increasingly sought-after alternative for new water supply in coastal areas. While three-quarters of the globe is covered with water, less than 0.3 percent is considered a renewable freshwater supply. More than half of the population in the United States lives within 50 miles (80 kilometers) of a coast, so the use of seawater as a source for potable water production is of great interest, especially in areas with stressed and overdrawn freshwater resources.
What are the different types of membranes used in water treatment?
Types of membranes.Water treatment processes employ several types of membranes1. They include microfiltration (MF), ultrafiltration (UF), reverse osmosis (RO), and nanofiltration (NF) membranes (Figure 1)2. MF membranes have the largest pore size and typically reject large particles and various microorganisms. UF membranes have smaller pores than MF membranes and, therefore, in addition to large particles and microorganisms, they can reject bacteria and soluble macromolecules such as proteins. RO membranes are effectively non-porous and, therefore, exclude particles and even many low molar mass species such as salt ions, organics, etc.2 NF membranes are relatively new and are sometimes called “loose” RO membranes. They are porous membranes, but since the pores are on the order of ten angstroms or less, they exhibit performance between that of RO and UF membranes3.
When was the first synthetic membrane made?
History. The first recorded synthetic membrane was prepared in 1867 by Moritz Traube19. His most successful membrane was a precipitated film of copper ferrocyanide which he used to study osmosis. His initial success spawned several decades of investigations into the theory behind the thermodynamics and kinetics of the diffusion process. In 1963, Loeb and Sourirajan demonstrated asymmetric cellulose acetate membranes which exhibited relatively high flux and good salt rejection20. RO membranes made their commercial debut when Gulf General Atomics and Aerojet General employed the Loeb-Sourirajan cellulose acetate (CA) membranes in spiral wound modules to purify water1.
