Membrane Bio-Reactor(MBR)
Membrane Bio-Reactor (MBR) is a new type of wastewater treatment system that combines membrane separation technology with biological treatment technology.
Replacing the traditional biological treatment technology terminal secondary sedimentation tank with membrane module, maintaining high activated sludge concentration in the bioreactor, increasing the biological treatment organic load, thereby reducing the sewage treatment facility footprint, and reducing residual pollution by maintaining low sludge load Mud amount.
The activated sludge and macromolecular organic matter in the tank are mainly intercepted by a membrane separation device immersed in an aerobic biological pool.
The concentration of activated sludge (MLSS) in the membrane bioreactor system can be increased to 8000~10000mg/L or even higher; the sludge age (SRT) can be extended to more than 30 days.
Membrane bioreactor can retain the microorganisms with long generation period due to its effective retention, and can realize deep purification of sewage. At the same time, nitrifying bacteria can fully reproduce in the system, and its nitrification effect is obvious, which provides the possibility of deep phosphorus removal and nitrogen removal. .
China is a water-deficient country, and sewage treatment and reuse is an effective way to develop and utilize water resources. The reuse of sewage is to treat urban sewage and industrial sewage through membrane bioreactors, and then use it to beautify, wash, and make up for ornamental water bodies. Urban sewage and industrial sewage are available nearby, which can eliminate long-distance water transportation, and complete the full utilization of water resources by the nearest treatment. The sewage can be treated nearby, and sewage can be prevented from leaking during long-distance transportation, resulting in pollution of groundwater. source. Wastewater reuse has been widely used in many water-deficient areas of the world and is considered to be the most useful technology for wastewater treatment in the 21st century.
Membrane classification
There are many types of membranes, which can be classified according to the separation mechanism, the properties of the membrane, and the structure of the membrane.
According to the separation mechanism
There are reaction membranes, ion exchange membranes, permeable membranes, and the like.
According to the nature of the film
There are natural membranes (biofilms) and synthetic membranes (organic membranes and inorganic membranes).
According to the type of film
There are flat type, tube type, spiral type and hollow fiber type.
MBR
Membrane Bioreactor (MBR) is a new type of water treatment technology combined with a membrane separation unit and a biological treatment unit. The membrane module replaces the secondary sedimentation tank and adheres to the high activated sludge concentration in the bioreactor to reduce the sewage treatment equipment footprint. And reduce the amount of sludge by insisting on low sludge load. Compared with the traditional biochemical water treatment skills, MBR has the following main features: high processing efficiency, good effluent quality; compact equipment, small footprint; easy to complete automatic control, simple operation management. Since the 1980s, this skill has received more and more attention and has become one of the hot spots of research. Membrane bioreactors have been used in more than a dozen countries including the United States, Germany, France and Egypt, with plans ranging from 6m3/d to 13000m3/d.
China has been studying MBR for less than a decade, but it has developed very rapidly. The domestic research on MBR can be roughly divided into several aspects: (1) exploring different combinations of biological processing skills and membrane separation units, and the bioreaction processing skills are extended from activated sludge method to contact oxidation method, biofilm method, and activity. Compound skills and two-phase anaerobic skills combined with sludge and biofilm; (2) discussion of factors, mechanisms and mathematical models affecting treatment effects and membrane fouling, and appropriate operating conditions and skill parameters to minimize membrane Pollution, processing capacity and operational stability of the advanced membrane module; (3) Expanding the use scale of MBR, MBR's research goal extends from day sewage to high-concentration organic wastewater (food wastewater, beer wastewater) and refractory industrial wastewater (petrochemical wastewater) , printing and dyeing wastewater, etc.)
MBR treatment process characteristics
1) The treatment efficiency is high, and the effluent can be directly reused. Since the hollow fiber membrane has an efficient separation effect on the mixture of the biochemical reactor, the sludge can be completely separated from the effluent, so that the SS and turbidity of the effluent can be made close to zero. At the same time, since the loss of activated sludge is almost zero, the concentration of activated sludge in the biochemical reactor can be about 2 to 6 times higher than that of the conventional process, which greatly improves the nitrogen removal capacity.
2) The system runs stably, the process is simple, the equipment is small, and the floor space is small. Due to the high concentration of activated sludge in the MBR technology, the volumetric load of the device is large; the impact resistance to the fluctuation of the influent water is good, and the operation is stable. In addition to greatly reducing the volume of the biochemical reactor-aeration tank, the process can miniaturize equipment and structures, and even eliminate the primary sedimentation tank and the secondary sedimentation tank, which reduces the system footprint.
3) The sludge is long and the amount of excess sludge is small. When the sludge concentration is high and the influent load is low, the ratio of nutrient to microorganism (F/M) in the system is low, and the sludge age becomes long. When the F/M maintains a low value, the growth of the activated sludge is close to zero, which reduces the disposal cost of the excess sludge.
4) Easy operation and management, easy to implement automatic control. Since the membrane separation allows the activated sludge to be completely trapped in the bioreactor, the hydraulic retention time (HRT) and sludge residence time (SRT) in the bioreactor are completely separated, so that it can be controlled flexibly and stably; At the same time, it is very easy to implement automatic control and improve the automation level of sewage treatment.
Application field
Organic wastewater treatment
Wastewater treatment of various beverage factories, wineries, food factories, animal husbandry plants, slaughter plants, dyeing and finishing plants, leather factories, pulp mills, pharmaceutical plants, high-concentration organic treatment plants, process improvement of old sewage plants, reverse osmosis System pre-processing
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