In the late 1960s, the Dorr-Oliver organization pioneered the development of the first MBR for office use and shipped it to ship wastewater treatment. At that time, the split-type configuration was commonly used, and the actual engineering currently uses immersed MBR. In the late 1980s, Japan and the United States successively pioneered the hollow MBR process (immersion type). From 1985 to 1995, Jhetford organized and promoted the separate Cycle-Let process (multi-tube type), which was applied to the wastewater reuse project in the United States. Although the development of MBR technology in China started late compared with foreign countries, the MBR Inquiry applications are not synchronized with foreign investigations, and some regions are among the best in the world. MBR technology is a combination of biochemical reactions and membrane separation, eliminating the need for a secondary sedimentation tank, and implementing mud-water separation by membrane modules. In MBR, the sludge retention time (SRT) can be controlled independently of the hydraulic retention time (HTR), which can ensure that the slow-growing microorganisms of the nitrifying bacteria are completely retained in the system and meet the growth cycle of the nitrifying bacteria.
The alternating anaerobic / hypoxic-membrane bioreactor (A-A / A-M) process can improve the nitrogen and phosphorus removal effect of domestic sewage. The process consists of an alternating anoxic / anaerobic reaction cell and an aerobic cell with a built-in membrane filtration unit. By changing the flow direction of the returning sludge at the bottom of the aerobic tank, anoxic and anaerobic environments are formed in sequence in the two independent reactors (A and B), and simultaneous anaerobic phosphorus release, anoxic denitrification and denitrification, and aerobic are achieved. Phosphorus absorption, nitrification, and BOD removal. The aerobic reactor performs continuous aeration to slow down the process of membrane fouling and extend the cleaning cycle. The average removal rates of COD, TN and TP by this process reached 93%, 67.4% and 94.1%, respectively.
2.2 A²/0 + MBR Craft
A² / 0 + MBR technology is a combination of past A² / 0 technology and MBR technology, so that their advantages complement each other and cooperate with each other, which can effectively eliminate the main pollutants. The high sludge concentration in the A² / 0 + MBR system not only reduces the hydraulic retention time, but also has the stages of simultaneous nitrification and denitrification and denitrification and phosphorus removal. Excellent nitrogen and phosphorus removal effect. The A2 / 0 + MBR process was used to treat urban sewage. The test proved that the sludge concentration of the MBR tank reached 8.2g / L, and the removal rates of CODCr, TN and ammonia nitrogen reached 93.0%, 78.5% and 94.7%, respectively.
Project name Traditional water treatment process MBR process composition of pretreatment-biological reaction tank-sedimentation tank-coagulation tank-sedimentation tank-filtration-disinfection-clear water tank pretreatment-MBR tank-disinfection-clear water tank construction requirements are not easy to achieve modular design According to the maximum design capacity, it is easy to realize a modular design when it is built at one time. It is suitable for staged construction. The requirements for saving investment sites are not limited by the setting sites. The A standard is better than the current national level A standard. The size of the remaining activated sludge is large. The remaining activated sludge has a large output, and the sludge treatment costs are high. The remaining activated sludge production is small. There are many operating management equipment, complicated management, and the possibility of failure. Larger, generally requires less professional maintenance equipment, simple process, easy to achieve full automatic control, stable and reliable operation, simple training can be taken care of. Generally, it is limited to flushing, road cleaning and urban greening. The effluent water is of good quality and can be widely used in Reuse of landscape water, etc.
In the face of increasingly strict standards for sewage discharge and reuse, many existing sewage treatment plants are being rebuilt and expanded to increase the amount of treated water without increasing the area and improve the quality of the effluent. Although MBR's capital expenditure is higher than the previous activated sludge process, which is prone to membrane pollution problems, its small footprint and high organic removal rate can also strengthen the nitrogen and phosphorus removal effect and ensure excellent water quality, which makes it suitable for urban sewage It has great potential in the application of nitrogen and phosphorus removal, and it also meets the requirements of upgrading and expanding the sewage treatment plants in China. Therefore, MBR has a good development prospect in the water plant reconstruction and expansion project.
Compared with the traditional treatment process, MBR process has higher initial construction and maintenance management costs, and the sewage treated by MBR can be directly reused. In the context of water scarcity, sewage is also an important water resource, and the demand for wastewater treatment and reuse will gradually increase in the future. Therefore, the MBR process will also become the preferred solution for large-scale wastewater treatment plants. At present, China is in the construction period of municipal sewage treatment facilities, which also provides opportunities for the MBR process. In summary, MBR has broad application prospects in the treatment of urban sewage, industrial wastewater, reuse of reclaimed water, and reconstruction and expansion of sewage treatment plants.