Ultrafiltration Reverse Osmosis UF/RO Water Purification Solution
Ultrafiltration reverse osmosis ( UF/RO) system is a kind of high efficient filter technology for water treatment. The solution combines two technologies, ultrafiltration and reverse osmosis, which can effectively remove suspended solids, particles, bacteria, viruses, organic matter and other impurities in water to obtain pure water quality. In here, we will introduce the principle, application field, characteristics and process flow of ultrafiltration reverse osmosis system.
Principle of ultrafiltration reverse osmosis system
Ultrafiltration reverse osmosis system is mainly composed of ultrafiltration membrane and reverse osmosis membrane. Ultrafiltration membranes have large pore sizes and can filter out most particles, organic matter and microorganisms. Reverse osmosis membranes are more refined and can effectively remove dissolved substances and tiny contaminants from water.
In the ultrafiltration reverse osmosis, the source water is initially filtered through the ultrafiltration membrane to remove most of the suspended solids and particles. The water filtered by the ultrafiltration membrane is called pre-treated water. Then, the pretreatment water through the reverse osmosis membrane under the high pressure, the dissolved substances and small pollutants reverse osmosis, to obtain pure water.
The key of ultrafiltration reverse osmosis system lies in the selection of membrane and the control of operating parameters. The choice of membrane needs to take into account the water quality of the source, investment cost and daily operation and maintenance. The control of operation parameters includes membrane surface pressure, water flow velocity and recovery rate, etc. Reasonable operation parameters can improve the processing efficiency of the system and reduce energy consumption.
Application field of ultrafiltration reverse osmosis solution
Ultrafiltration reverse osmosis solutions are widely used in the following fields:
Drinking water purification treatment
Ultrafiltration reverse osmosis system can remove contaminants such as suspended solids, bacteria, viruses, and organic matter from water to obtain safe and clean drinking water. Ultrafiltration reverse osmosis can play an important role in urban water supplies and where drinking water is difficult in remote areas.
Industrial water purification treatment
In some industrial production system, a large amount of clean water is needed. Ultrafiltration reverse osmosis equipment can effectively remove impurities and pollutants in water to meet the quality requirements of industrial water. Especially in electronics, chemical, pharmaceutical and other industries, ultrafiltration reverse osmosis is widely used.
Sewage purification treatment and reuse
Ultrafiltration reverse osmosis equipment can separate useful substances and water in sewage, and realize wastewater treatment and reuse. Through the treatment of ultrafiltration and reverse osmosis, wastewater can be treated into water quality that meets discharge standards, contributing to environmental protection and resource recovery.
Advantages and disadvantages of ultrafiltration reverse osmosis systemThe ultrafiltration reverse osmosis solution has the following advantages:
Efficient filtration: it can remove contaminants such as particles, bacteria, viruses and organic matter from water.
Good water purification effect: the obtained water quality is pure, in line with the quality requirements of drinking water and industrial water.
Energy savings: Ultrafiltration reverse osmosis solutions consume less energy than traditional filtration methods.
Wide application: can be used in drinking water treatment, industrial water treatment and sewage treatment and reuse and other fields.
However, the ultrafiltration reverse osmosis solution also has some disadvantages:
High operation and maintenance costs: The system requires regular cleaning and maintenance, which increases operating costs.
High requirements for water quality: the quality of source water has a certain impact on the effect of ultrafiltration reverse osmosis, which needs to be treated in the early stage.
As an efficient water treatment technology, ultrafiltration reverse osmosis water purification system is widely used in drinking water treatment, industrial water treatment, and sewage treatment and reuse. Through rational selection of membranes and control of operating parameters, pure water quality can be obtained to meet the needs of different application fields. Although the ultrafiltration reverse osmosis system has some disadvantages, its advantages far outweigh its disadvantages. With the advancement of technology and the reduction of cost, it is believed that ultrafiltration reverse osmosis solution will be more widely used in the future.
Ultrafiltration reverse osmosis processUltrafiltration process
1. Raw water pretreatment: the raw water through dosing, mixing, coagulation, filtration and other processes, reduce SS, colloid, microorganisms and other impurities in the raw water.
2. Ultrafiltration: the pretreated water is passed through the ultrafiltration membrane to separate substances of different sizes and remove harmful substances such as macromolecular organic matter, colloidal particles and microorganisms.
3. Uv disinfection: the ultrafiltration water is treated by UV to remove the microorganisms remaining in the water.
4. Water purification: the water after pretreatment, ultrafiltration and UV disinfection, to meet the standard of secondary water supply.
Reverse osmosis process1. Raw water pretreatment: same as the ultrafiltration process mentioned above.
2. Primary pressure filtration: the pretreated water is filtered through primary pressure to remove harmful substances such as macromolecular organic matter, colloidal particles and microorganisms.
3. Primary reverse osmosis: the water after primary filtration is passed through the reverse osmosis membrane to remove inorganic salts and heavy metal plasma in the water.
4. Secondary pressure filtration: the water after primary reverse osmosis filtration is pressure filtered again to remove impurities such as organic matter and microorganisms remaining in the water.
5. Secondary reverse osmosis: the water after secondary pressure filtration is passed through the reverse osmosis membrane again to completely remove the inorganic salts and heavy metal plasma in the water.
6. Concentrated water treatment: the concentrated water of the secondary reverse osmosis membrane is recovered through recirculation, concentration and other technologies to reduce water waste.
7. Purified water: the water treated by pretreatment, pressure filtration and reverse osmosis will reach the standard of high pure water.
Ultrafiltration reverse osmosis process is widely used in industrial, rural, urban and other different fields of water treatment, for the preparation of high purity water, food processing, drinking water, water supply, etc., and can be combined according to the actual situation to achieve different water quality requirements.
Key process of ultrafiltration reverse osmosis technology
Using ultrafiltration reverse osmosis membrane technology to treat wastewater, the key is to prevent fouling and scaling of membrane components, and ensure the water flux of membrane. Adopt the following measures to control the fouling and fouling risk of the membrane.
Addition of flocculant, coagulant aid and soda: adding appropriate amount of flocculant (PAC), coagulant aid (PAM) and sufficient amount of soda in the flocculation reaction tank can remove more than 95% of Ca2+ and part of heavy metal ions after precipitation in the inclined plate sedimentation tank, so as to reduce the possibility of forming insoluble heavy metal precipitation on the surface of the subsequent reverse infiltration membrane.
Since PAM is a long-chain polymer compound, it is similar to the polymer material of RO film. After excess PAM reaches RO film, RO film will be seriously polluted and blocked, and membrane flux cannot be recovered by chemical cleaning. Therefore, only an appropriate amount of coagulant aid can be added, and the combined dosage of PAC and PAM can be determined according to the field trial.
Acid addition: Because the original wastewater is alkaline and has a high pH, heavy metal ions are easy to form insoluble precipitates in an alkaline environment and form scale on the membrane surface. It is very important to adjust the pH of raw water to prevent heavy metal ions from settling and scaling on the membrane surface. Add hydrochloric acid to the inlet pipe of the multi-medium filter of the water produced in the sedimentation tank, adjust the pH to 7~7.5, and effectively control the fouling of heavy metal ions on the surface of the reverse osmosis membrane.
Multi-medium filter: In order to effectively improve the water quality of the ultrafiltration membrane, a multi-medium filter is set in front of the ultrafiltration membrane. The multi-medium filter uses coarse quartz sand, fine quartz sand and flaked anthracite as the filter medium. After the wastewater is filtered by the multi-media filter, the turbidity of the produced water remains at 1~2 NTU, which reduces the operating load of the subsequent ultrafiltration system and effectively reduces the fouling risk of the ultrafiltration membrane.
Addition of oxidant: In order to prevent the accumulation of suspended matter and microorganisms on the surface of ultrafiltration membrane and cause fouling, two oxidant (sodium hypochlorite) addition points are set in the ultrafiltration system, one is on the ultrafiltration inlet pipe and the other is on the ultrafiltration backwashing pipe. The addition of oxidant can make the transmembrane pressure difference (TMP) and water yield flux of ultrafiltration operation stably maintain at the designed level.
The addition of scale inhibitor: the concentration of SO42- in the original wastewater is very high, and heavy metal ions such as Ba2+ and Sr2+ can easily form insoluble salt with SO42-. In addition, Ca2+ and F- are also prone to form insoluble salts. These insoluble salts are the main factor of scale formation in reverse osmosis membrane operation. In order to prevent reverse osmosis membrane fouling effectively, appropriate scale inhibitor was added to the inlet pipe of reverse osmosis membrane.
After stable ultrafiltration water production, the whole water quality of ultrafiltration water production should be analyzed, and DOW FilmtecTM ROSA9.1 reverse osmosis calculation software should be used to calculate whether there is a risk of scaling when ultrafiltration water enters the reverse osmosis membrane. According to the analysis, there are fouling risks of BaSO4 and SrSO4 in the water produced by ultrafiltration into the reverse osmosis membrane, and the software suggests that scale inhibitor should be added to reduce the fouling risk on the surface. Using OSMOTREAT OSM35 scale inhibitor (Nalco Industrial Services Co., LTD.), this product can effectively reduce the fouling risk of refractory salts such as BaSO4, SrSO4 and CaF2 on the surface of reverse osmosis membranes. OSMAS calculation software was used to calculate the dosage of OSM35 scale inhibitor.
Ultrafiltration reverse osmosis process precautionsThe water source of the system is industrial wastewater after advanced treatment. In order to prevent the cumulative pollution of pollutants on the membrane surface, the following precautions should be paid attention to during the operation of the ultrafiltration reverse osmosis system.
Application of the Biological Deodorizer Treatment Systems
1. The ultrafiltration system should be backwashed once for 20~30 min. After eight times of backwashing, one enhanced backwashing was carried out to restore the filtration flux of
