Ultrafiltration is an idea and efficient alternative to reverse osmosis technology and it is best suitable for sewage water treatment. The UF system blocks infective microorganisms,chemicals and solutes of high molecular weight while low molecular weight solutes pass through.The employment of an UF membrane system is to confiscate the substances which contribute the taste, color, and odor of water. Ultrafiltration is similar to microfiltration, nanofiltration, reverse osmosis system or gas chlorination technology, except it differs in the molecule sizes it blocks.
Ultrafiltration (UF) is a filtration process similar to Reverse Osmosis, using hydro-static pressure to force water through a semi-permeable membrane. The pore size of the ultrafiltration membrane is usually 103 – 106 Daltons. Ultrafiltration (UF) is a pressure-driven barrier to suspended solids, bacteria, viruses, endotoxins and other pathogens to produce water with very high purity and low silt density.
Ultrafiltration (UF) is a variety of filtration in which hydrostatic pressure forces a liquid against a semi permeable membrane. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane. Ultrafiltration is not fundamentally different from reverse osmosis, microfiltration or nanofiltration, except in terms of the size of the molecules it retains.
Ultrafiltration (UF) is used to remove essentially all colloidal particles (0.01 to 1.0 microns) from water and some of the largest dissolved contaminants. The pore size in a UF system is mainly responsible for determining the type and size of contaminants removed. In general, membrane pores range in size from 0.005 to 0.1 micron. UF system manufacturers classify each UF product as having a specific molecular weight cutoff (MWC), which is a rough measurement of the size of contaminants removed by a given UF system. A 100,000 MWC UF membrane means that when water containing a given standard compound with a molecular weight of around 100,000 daltons is fed to the UF unit, nearly all of the compound will not pass through the membrane.
Substances with a molecular weight of 100,000 daltons have a size of about 0.05 microns to about 0.08 microns in diameter. UF systems are used where essentially all colloidal particles (including most pathogenic organisms) must be removed, but most of the dissolved solids may pass through the system without causing problems downstream or in the finished water. UF will remove most turbidity from water.
Ultrafiltration uses hollow fibers of membrane material and the feed water flows either inside the shell, or in the lumen of the fibers. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane. Ultrafiltration is not fundamentally different from reverse osmosis, microfiltration or nanofiltration, except in terms of the size of the molecules it retains. When strategically combined with other purification technologies in a complete water system, UF is ideal for the removal of colloids, proteins, bacteria, pyrogens, proteins, and macromolecules larger than the membrane pore size from water.
Ultrafiltration System (UF system) uses hollow fibers of diverse membrane filtrations where hydrostatic pressure pushes solvents against a very fine membrane. Which blocks suspended particulates and solids that are large while water and solutes with a lower molecular weight are allowed to flow through the membrane.Industry and research employ this separation process for purifying and concentrating macromolecular solutions, which are usually protein solutions. To meet critical discharge criteria, ultrafiltration systems remove the need for clarifiers and multi-media filters. Effective ultrafiltration systems use membranes that can be immersed, back-flushable, and air scoured. Spiral wound UF/MF membranes offer excellent performance for the clarification of process water and wastewater.
While other purification systems like UV kills bacteria and germs in drinking water itself, UF Filter is the only system that pulls out the eggs from water, hence ensuring a complete, drinkable, and safe water. UV systems additionally clean the bodies and eggs of both living and nonliving bacteria and virus from the water. UF systems are proven to fish out all those matters that contribute to the colour, taste, and odour of water. It quickly can cleanse the dirtiest water and make it suitable drinking.
Ultrafiltration system membranes can be made from both organic (polymer) and inorganic materials. There are several polymers and other materials used for the manufacture of UF membrane. The choice of a given polymer as a membrane material is based on very specific properties such as molecular weight, chain flexibility, chain interaction, etc. Some of these materials are polysulfone, polyethersulfone, sulfonated polysulfone, polyvinylidene fluoride, polyacrylonitrile, cellulosics, polyimide, polyetherimide, aliphatic poly-amides, and polyetherketone. Inorganic materials have also been used such as alumina and zirconia. The structure of UF membrane can be symmetric or asymmetric. The thickness of symmetric membrane (porous or nonporous) is range from 10 to 200 µm. The resistance to mass transfer is determined by the total membrane thickness.
A decrease in membrane thickness results in an increased permeation rate. Ultrafiltration membranes have an asymmetric structure, which consist of very dense to player or skin with thickness of 0.1 to 0.5 µm supported by a porous sub layer with a thickness of about 50 to 150 µm. These membranes combine the high selectivity of a dense membrane with the high permeation rate of a very thin membrane. The resistance to mass transfer is determined largely or completely by thin to player.
Industries that consume large volumes of water or discharge highly toxic effluent are candidates to employ ultrafiltration for water reuse. These include the chemicals, steel, plastics & resins, paper & pulp, pharmaceutical and the food & beverage industries, including soft drinks & canned foods, as well as power, water & wastewater treatment plants and others. Ultrafiltration is used to recycle flow or add value to later products and more. In many cases ultrafiltration (UF) is used for prefiltration in reverse-osmosis plants to protect the reverse-osmosis process. Ultrafiltration is an effective means of reducing the silt density index of water and removing particulates that can foul reverse osmosis system. Ultrafiltration is frequently used to pretreat surface water, seawater and biologically treated municipal water upstream of the reverse osmosis unit.
The Ultrafiltration method being a prominent wastewater treatment system, Combining different membrane technologies, ultrafiltration as a single treatment step or in combination with other filtration processes, provides a powerful tool to remove all kinds of contaminants from the raw water.
The removal efficiency of organic carbons that are very difficult to remove from the raw water in general, can be increased significantly by dosing of flocculant in front of the ultrafiltration system. Compared to conventional filtration, it is no more necessary to optimize the flocculation with regards to following separation by the filter due to the fact that ultrafiltration is able to reject even very small flocks. Therefore, flocculation can be optimized towards removal of organic carbons.
Adding active carbon in front of the ultrafiltration, substantially improves the removal efficiency of the system for humic substances and pesticides. In case that large quantities of active carbon are required, the application of a nanofiltration instead of an ultrafiltration system should be considered.
Polar pesticides can be reliably removed by applying a process combination of ultrafiltration and nanofiltration. As a positive side – effect, the water will also be softened and sulfate will be removed.
To desalinate water, a reverse osmosis treatment step can be applied after the ultrafiltration process. With ultrafiltration as pretreatment, the reverse osmosis system can be operated more reliably and with higher flux rates. Ultrafiltration as a pre-treatment for reverse osmosis is a reliable barrier for microorganisms and particles. Furthemore, it almost completely removes fouling causing substances.
Comparison with conventional treatment:
Compared to conventional treatment processes, ultrafiltration offers various advantages:
UF method is used in certain industries to accommodate reuse. Austro’s UF system employs an independent and efficient UF system. For more information about UF system, contact us.