Membrane pore size cutoffs used for these types of separation are typically in the range of 0. Reverse osmosis ro is a membrane separation process, driven by a pressure gradient, in which the membrane separates the solvent generally water from other components of a solution. Membrane filtration can be classified into microfiltration mf, ultrafiltration uf, nanofiltration nf and hyperfiltration reverse osmosis. Pdf nowadays mining water flowing out of an ore mine can be a serious threaten to the environmental due to high content of metals, especially heavy.
Difference between ultrafiltration and reverse osmosis. Basics of reverse osmosis puretec industrial water. Mf and uf is a pressuredriven membrane separation process that helps removes particulate matter from aqueous solutions such as water. Dead end membrane filtration michigan state university. Microfiltrationreverse osmosis ocean water desalination pilot. There are many steps involved in the water purification process. Reverse osmosis ro reverse osmosis is a high pressure, energye. This first chapter provides a general introduction to the reverse osmosis ro and nanofiltration nf membrane treatment processes. Desalination technologies and filtration processes. Ro systems can be designed optimally to recirculate. Newater technology stage 1 first stage the first stage of the newater production process is known as microfiltration mf. A twostep process makes our microfiltration systems more efficient and reliable than conventional treatment methods.
A water treatment system combines a microfiltration or ultrafiltration membrane system with a downstream reverse osmosis membrane system. Water is forced to flow from the concentrated to the diluted side, and. Microfiltration mf is a pressuredriven separation process, which is widely used in concentrating, purifying or separating macromolecules, colloids and suspended particles from solution. Reverse osmosis ro is the process of forcing water from the dirty side through. Reverse osmosis, commonly referred to as ro, is a process where you demineralize or deionize water by pushing it under pressure through a semipermeable reverse osmosis membrane what is osmosis.
In reverse osmosis, the two solutions are still separated by a semipermeable membrane, but pressure is applied to reverse. Crossflow membrane filtration technology is quickly gaining global acceptance as an important manufacturing step in many of the process lines in the food, dairy. Microfiltration, ultrafiltration, nanofiltration and reverse osmosis are related membrane processes differing in the size of the material retained by the membrane. In reverse osmosis, an applied pressure is used to overcome osmotic pressure, a colligative property that is driven by chemical potential differences of the solvent, a thermodynamic parameter.
Membrane filtration is employed in the removal of fine particles less than 2. Reverse osmosis ro is a water purification process that uses a partially permeable membrane to remove ions, unwanted molecules and larger particles from drinking water. West basin municipal water district 17140 avalon blvd. In principle, only water passes through the membrane layer. The combined microfiltration mf and reverse osmosis ro process has been one of the mostly employed treatment methods in obtaining recyclable quality for wastewater reclamation and reuse, yet. Pre and postfilters are often incorporated along with the reverse osmosis. Microfiltration reverse osmosis ocean water desalination pilot plant project submitted by. Microfiltration is often used in conjunction with other separation processes such as ultrafiltration and reverse osmosis.
The pressure is called osmotic pressure and this process is osmosis. They include microfiltration mf, ultrafiltration uf, reverse osmosis ro, and nanofiltration nf membranes. The subjects addressed in this chapter should serve as the basic foundation for a broader understanding of ro and nf processes as applied to potable water, industrial process water, tertiary. Reverse osmosis and ultrafiltration in reverse osmosis only water and a portion of nonprotein nitrogen pass through the membrane fleming, 1999. Combination technology of ceramic microfiltration and.
Comparison of membrane processes applied membranes, inc. Nano filtration nf and reverse osmosis ro membranes have. Us9227159b2 combined microfiltration or ultrafiltration. Our technologies are made to handle a wide range of process. Table 11 summarizes some of this same information in tabular form, including the various membrane process.
Common applications include preconcentration of dairy or food streams prior to evaporation, polishing of evaporator condensate, and purifi cation of process water. Principle of reverse osmosis and its process notes pdf ppt. Microfiltration systems remove inorganic, organic, or. Ultrafiltration, nanofiltration and reverse osmosis. Microfiltrationreverse osmosis ocean water desalination. To understand the purpose and process of reverse osmosis you must first understand the naturally occurring. Filmtec reverse osmosis ro and nanofiltration nf membrane technologies are widely. Table 1 shows the amount of components that were left after the process of reverse osmosis. Nf operates in the realm between uf and reverse osmosis.
The ro process comprised a pressure vessel housing. Pdf the application of microfiltrationreverse osmosis. In reverse osmosis, the two solutions are still separated by a semipermeable membrane, but pressure is applied to reverse the natural flow. Reverse osmosis, ultra and diafiltration and microfiltration. This forces the water to move from the more concentrated solution to the weaker. First, chemical pretreatment converts the contaminants to filterable particulates and mitigates fouling effects. Membrane filtration gea engineering for a better world. Microfiltrationreverse osmosis ocean water desalination pilot plant project.
Membrane processes in biotechnology and pharmaceutics, 2012. In membranes where pore flow contributes significantly to flux. Newater technology stage 1 first stage reverse osmosis. Microfiltration is the process of physically removing suspended solids from water, usually through a membrane. Reverse osmosis systems use a process that reverses the flow of water in a natural process of osmosis so that water passes from a more concentrated solution to a more dilute solution through a semipermeable membrane.
It is commonly used in conjunction with various other separation processes such as ultrafiltration and reverse osmosis. Nanofiltration nf and reverse osmosis ro membranes have. To avoid build up of contaminants, cross flow filtration allows water to sweep away contaminant build up. Pdf combination treatment of corn starch wastewater by. Ultrafiltration, nanofiltration and reverse osmosis what is filtration. Pdf combined microfiltration and reverse osmosis process. In reverse osmosis, the two solutions are still separated by a semipermeable membrane, but pressure is applied to reverse the natural flow of the water.
Reverse osmosis uses a multistep filtration process designed to remove impurities, transforming your drinking water into freshtasting, pure water thats refreshing to drink. To understand the purpose and process of reverse osmosis you must first understand the naturally occurring process of osmosis. Mf and uf is a pressuredriven membrane separation process. Microfiltration can also be used in sample preparation to remove intact cells and some cell debris from the lysate. Process nf ro uf mf cf examples of common constituents in water metal ions sugar virus pyrogen colloidal silica carbon fines bacteria approx. Conventionally, microfiltration mf, ultrafiltration uf, nanofiltration, reverse osmosis, membrane bioreactors mbrs, etc. Microfiltration is a type of physical filtration process where a contaminated fluid is passed through a special poresized membrane to separate microorganisms and suspended particles from process liquid. The membrane processes discussed here are microfiltration mf, ultrafiltration uf, nanofiltration nf, and reverse osmosis ro. In the reverse osmosis situation, water passes through the membrane to the diluted solution leaving behind suspended particles and salt. Microfiltration water microfiltration microfiltration. Reverse osmosis reverse osmosis ro separates salts and small molecules from low molecular weight. Reverse osmosis is a process which occurs when pressure, greater than the osmotic pressure, is applied to the concentrated solution. Ultrafiltration, nanofiltration and reverse osmosis safe. Humans worked out how to copy this process around 40 years ago for the same reason to desalinate seawater.
Reverse osmosis ro reverse osmosis is a high pressuredriven membrane filtration process which is based on a very dense membrane. Filtration is a process of removing particulate matter from water by forcing the water through a porous media. Microfiltration is the process of physically removing suspended solids from water, through a membrane. Microfiltration or ultrafiltration, plus reverse osmosis 52 microfiltration or ultrafiltration, plus nanofiltration 53 ion exchange 53 zero liquid discharge 53 references 55 list of tables table 1. Microfiltration, nanofiltration and reverse osmosis for the removal. Reverse osmosis, nanofiltration, ultrafiltration and. Membrane technologies can be used in combination, such as ultrafiltration followed by reverse osmosis for seawater desalination processes, and microfiltration followed by nanofiltration for clarification of fermentation broth and product concentration. Microfiltration mf and ultrafiltration uf are both processes by which a contaminated liquid is passed through a semipermeable membrane that removes solids too large to fit through the. The natural tendency is for water to move through the membrane from the dilute to the concentrated solution until chemicals reach equal concentrations on both sides of the membrane. Relatively insensitive to flow and total dissolved solids tds level and suitable for small systems with a high. The mf and uf membranes are used only for pretreatment while nanofiltration, reverse osmosis. Technical information on home water treatment technologies. In microfiltration, osmotic pressure is negligible, as c is of the order of 1. In this process, the treated used water is passed through membranes to filter.
Water purification is an important process in providing clean water to the community. Nanofiltration refers to a specialty membrane process which rejects particles in the approximate size range of 1 nanometer 10 angstroms, hence the term nanofiltration. When applied pressure exceeds the osmosis pressure, reverse osmosis will take place. Membrane filtration can be classified into microfiltration mf, ultrafiltration uf, nanofiltration nf and hyperfiltration reverse osmosis ro. Unlike nanofiltration and reverse osmosis, microfiltration only utilizes physical filtration to. This technology is used to treat surface water, ground water, sea water and waste water as either primary treatment or as pretreatment to reverse osmosis and nanofiltration. The growth of mf and uf as a treatment process has followed a substantially different path from that of the established desalting membrane processes of reverse osmosis ro and nanofiltration nf. Pdf the fate of organic micropollutans mps in a membrane system based on microfiltration.
242 455 478 1128 1612 42 858 498 1061 1072 380 296 22 1133 1548 360 714 659 1363 649 343 934 87 1277 651 812 1108 1401 1275 436 1301 244