YASA ET MEMBRANES
FOR WASTEWATER TREATMENT

Membrane technologies have developed as one of the main contributors to the resolution of water-related problems over the past two decades. Increasing water scarcity, followed by severe regulations in industrialized countries, have promoted the use of membranes for water and wastewater treatment.

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In water and wastewater treatment, membrane technology has been recognized as the key technology for the separation of contaminants from polluted sources. 

 

Membranes are selective barriers that separate two different phases, allowing the passage of certain components and the retention of others. The driving force for transport in membrane processes can be a pressure gradient and chemical or electrical potential across the membrane.

 

Membrane processes depend on a physical separation, usually with no phase change and chemicals addition in the feed stream, thus stand out as an alternative wastewater treatment technique to conventional processes.

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From the perspective of wastewater treatment, microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) are the most common developed membrane separation techniques applied in industries.

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YASA ET Microfiltration (MF) Membranes

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Microfiltration usually serves as a pre-treatment for other separation processes such as ultrafiltration, and a post-treatment for granular media filtration.

 

The typical particle size used for microfiltration ranges from about 0.1 to 10 µm. In terms of approximate molecular weight these membranes can separate macromolecules generally less than 100,000 g/mol.

 

The filters used in the microfiltration process are specially designed to prevent particles such as, sediment, algae, protozoa or large bacteria from passing through a specially designed filter. More microscopic, atomic or ionic materials such as water (H2O), monovalent species such as Sodium (Na+) or Chloride (Cl−) ions, dissolved or natural organic matter, and small colloids and viruses will still be able to pass through the filter. 

 

The exit process stream after treatment using a micro-filter has a recovery rate which generally ranges to about 90-98 %.

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YASA ET Ultrafiltration (UF) Membranes

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Ultrafiltration (UF) is a variety of membrane filtration in which forces like pressure or concentration gradients lead to a separation through a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained in the so-called retentate, while water and low molecular weight solutes pass through the membrane in the permeate.

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YASA ET Ultrafiltration (UF) membranes are used to remove all colloidal particles (0.01 to 1.0 microns) from water and some of the largest dissolved contaminants. The pore size in a UF membrane 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.

 

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YASA ET Nanofiltration (NF) Membranes

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Nanofiltration (NF) is one of the widely used membrane processes for water and wastewater treatment in addition to other applications such as desalination.

 

NF has replaced reverse osmosis (RO) membranes in many applications due to lower energy consumption and higher flux rates.

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Unlike RO, which has high rejection of virtually all dissolved solutes, NF provides high rejection of multivalent ions, such as calcium, and low rejection of monovalent ions, such as chloride.

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Typically, YASA ET nanofiltration (NF) membranes can reject particles as small as 0.001 μm whereas reverse osmosis systems can reject particles of size up to 0.0001 μm.

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YASA ET Reverse Osmosis (RO) Membranes

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Reverse osmosis is a water purification process that uses a semi-permeable membrane (synthetic lining) to filter out unwanted molecules and large particles such as contaminants and sediments like chlorine, salt, and dirt from wastewater.

 

In addition to removing contaminants and sediments, reverse osmosis can also remove microorganisms. It gets water clean down to a molecular level, leaving only pure H2O behind.

 

Reverse osmosis (RO) membranes have been shown to significantly reduce total dissolved solids, heavy metals, organic pollutants, viruses, bacteria, and other dissolved contaminants in wastewater. The RO membranes are usually operated at high pressures to achieve the maximum throughput and thus optimize the capital and energy costs.

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The fraction that appears in the product is usually measured in terms of the rejection coefficient of the membrane. YASA ET Reverse Osmosis membrane has a salt rejection of more than 99.5%.

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