Process and working principle of MBR integrated equipment

MBR Membrane bioreactor is a new and efficient wastewater treatment technology that combines efficient membrane separation technology with traditional activated sludge method. It uses a uniquely structured MBR flat sheet membrane module placed in the aeration tank. After aerobic aeration and biological treatment, the water is pumped through the filter membrane and extracted. MBR Wastewater treatment is significantly different from traditional wastewater treatment methods. A membrane separation device replaces the secondary sedimentation tank and tertiary treatment processes in traditional processes. This results in high-quality effluent, solving the problem of traditional environmental protection equipment not meeting the requirements for reclaimed water reuse. MBR The treated wastewater can be directly used as municipal water or further processed for various industrial uses.

      Due MBR to the presence of the membrane, the system's solid-liquid separation capacity is greatly improved, resulting in MBR a significant improvement in the effluent quality and volumetric load of the membrane bioreactor. The water quality after membrane treatment is high (exceeding the national Class A A standard). After disinfection, high-quality reclaimed water with high water quality and biological safety is finally formed, which can be directly used as a new water source. Due to the filtration effect of the membrane, microorganisms are completely retained in the MBR membrane bioreactor, achieving a complete separation of hydraulic retention time and activated sludge age, eliminating the sludge bulking problem in the traditional activated sludge method. MBR Membrane bioreactors have high pollutant removal efficiency, strong nitrification capacity, good simultaneous nitrification, denitrification, and nitrogen removal effects, stable effluent quality, low excess sludge production, compact equipment, small footprint (only 1/3-1/2 of traditional processes), convenient capacity expansion, high degree of automation, and simple operation.

MBR The membrane bioreactor component series has the advantages of compact structure, beautiful appearance, small footprint, low operating cost, stability and reliability, high degree of automation, and convenient maintenance and operation. MBR The effluent water quality of wastewater treatment is good and superior to the reclaimed water quality standard. And with unique MBR flat sheet membrane technology, it overcomes many shortcomings of general hollow fiber membranes and is a leading international wastewater treatment product and equipment. MBR The series of membrane modules for membrane bioreactors have formed standardized series products. Each module consists of 50 - 150 standard flat membrane sheets. It can also be individually designed according to user needs to meet user requirements.

MBR Integrated equipment uses membrane bioreactors ( MBR ) for wastewater treatment and reuse. It has all the advantages of membrane bioreactors: good effluent quality, low operating cost, strong system shock resistance, low sludge volume, and high degree of automation. In addition, as an integrated equipment, it has a small footprint and is easy to integrate. It can be used as a small wastewater reuse equipment, or as the core processing unit of a larger wastewater treatment plant (station). It is one of the current research hotspots in the field of wastewater treatment and has broad application prospects.

I. Working Principle

      Membrane bioreactor ( MBR ) technology is a new wastewater treatment technology that organically combines membrane separation technology with biotechnology. It uses membrane separation equipment to retain activated sludge and macromolecular organic substances in the biochemical reactor, eliminating the need for a secondary sedimentation tank. The activated sludge concentration is therefore greatly increased, and the hydraulic retention time ( HRT ) and sludge retention time ( SRT ) can be controlled separately, while refractory substances continuously react and degrade in the reactor.

      Therefore, membrane bioreactor ( MBR ) technology greatly enhances the function of the bioreactor through membrane separation technology. Compared with traditional biological treatment methods, it is one of the most promising new wastewater treatment technologies.

      The basic structure is shown in the figure below:

II. Equipment Performance Parameters:

MBR The core component of the integrated equipment is the membrane bioreactor, and the influent water quality requirements are as follows:

COD<500mg/L ；

BOD5<300mg/L ；

SS<100mg/L ；

NH3-N<50mg/L ；

Number of E. coli <10000 /L；

      The integrated equipment can flexibly configure the process flow according to the raw water quality, making it widely applicable. It can directly treat domestic sewage and hospital sewage to meet the standards for domestic miscellaneous water.

III. Effluent Water Quality:

Effluent water quality meets the standards for domestic miscellaneous water:

COD<50mg/L ；

BOD5<10mg/L ；

SS<10mg/L ；

NH3-N<10mg/L ；

Number of E. coli <3 /L；

IV. Typical Process Flow:

MBR The process flow of integrated equipment for treating domestic sewage is shown in the figure below:

      This technology is an advanced wastewater treatment technology. Its core is based on immersed high-strength hollow fiber membrane separation and bioreactor technology, integrating a suspended growth bioreactor with an ultrafiltration membrane separation system, replacing the secondary sedimentation tank and sand filtration system in the traditional activated sludge treatment system with ultrafiltration membrane separation. Its characteristic is that the treated water quality is very good, with low suspended solids, CODcr 、NH3-N、BOD5 and turbidity, and can be directly reused as miscellaneous water, such as domestic miscellaneous water (excluding drinking water), landscape greening, car washing; industrial water, such as circulating cooling water or directly as reverse osmosis feed water, boiler feed water and ultrapure water for the electronics industry.

      Ultrafiltration membranes are usually directly immersed in the aeration tank, directly contacting the mixed liquid of the biological reaction, and the filtered water is passed through the external pressure hollow fiber membrane to achieve solid-liquid separation by negative pressure suction of the filter pump. The pressure difference of negative pressure suction is very low, with a maximum of 2.2 meters of water head, and the energy required per unit of treated water is relatively small. During the filtration process, air is introduced into the bottom of the membrane by a blower. On the one hand, the turbulence generated by the rising airflow produces a scrubbing effect on the outer surface of the hollow fiber membrane, which can continuously remove the solid substances adhering to the membrane surface, preventing or reducing membrane fouling or blockage; on the other hand, this airflow also has an aeration effect, which can provide most of the oxygen consumption required for biodegradation. The remaining part of the oxygen required for biodegradation must be completed through the diffused aeration system. Excess sludge produced in the biological reaction is directly discharged from the ultrafiltration membrane pool.

V. Main Advantages

MBR Membrane bioreactors in MBR wastewater treatment and MBR middle water reuse projects have the following very prominent advantages:

      1、 MBR Membrane bioreactors have high pollutant removal efficiency and good treated effluent quality;

      2、 MBR Membrane bioreactors have high sludge concentration, large reactor volume load, and small footprint;

      3、 MBR Membrane bioreactors are conducive to the retention of slow-growing or high-efficiency microorganisms, improving the nitrification effect of the system and the treatment capacity of refractory organic matter;

      4、 MBR Membrane bioreactors produce low amounts of excess sludge;

      5、 MBR Membrane bioreactors are easy to achieve automatic control and convenient operation and management;

      6 After treatment, the discharged water SS and turbidity are close to zero, enabling reuse.

VI. MBR (Membrane Bioreactor) ) Process Characteristics:

      1、 Degrades organic matter in wastewater, nitrifying bacteria convert NH3-N nitrification into NO3- The organic matter removal rate is above 95% The ammonia nitrogen removal rate is above 97% above.

      2 The pretreatment process is simple, does not require a large amount of chemical addition, and the operation process is simple;

      3、 High recovery rate, water recovery rate can reach 99% above. This flexibility allows operators to reduce the recovery rate to reduce the membrane " pressure ” when the quality of the influent raw water deteriorates, but at the same time produce the same total amount and quality of purified water;

      4 The system uses a logical process monitoring system, including flow transmitters and pressure transmitters, etc. This highly controlled system approach can be used to design the most flexible system and improve the minimum requirements of the operator interface;

      5 Air scouring ensures reliable operation under various inflow conditions;

      6、 Automatic backwashing ensures higher overall membrane flux at lower transmembrane pressure;

      7 Small footprint, only 10 ~ 20%；

      8 of traditional processes; 7 Long service life, continuous operating time can reach 10,000 hours, broken wire rate less than 1%。