Is MBR Integrated Equipment Worth [$] To You?

MBR (membrane bio-reactor) is a combined process that combines biological treatment and membrane separation. A hollow fiber membrane module is placed in the bio-reactor, and the filtration hollow fiber membrane is an ultrafiltration membrane (UF) or microfiltration membrane (MF) with a pore size range from 0.01-0.3μm, mainly used for retention of suspensions and organics. Its characteristics can maintain a certain concentration of microorganisms in the biological reaction tank and purify sewage.

MBR is a new high-efficiency wastewater treatment process that combines the high-efficiency membrane separation technology with traditional activated sludge method. It uses a unique structure of MBR module to be placed in an aeration tank and subjected to aerobic exposure. The aeration and biologically treated water are pumped out by a pump, the water is filtered through the fiber. MBR sewage treatment is very different from traditional sewage treatment methods. The bio-reactor tank are used to replace the secondary tank and tertiary treatment processes in the traditional process. In this way, high-quality effluent is obtained, and the problem that the effluent quality of traditional environmental protection equipment for sewage treatment fails to meet the requirements for reclaimed water reuse. MBR sewage treated water can be directly used as municipal water or further treated as various industrial water.

The existence of MBR membrane has greatly improved the system’s solid-liquid separation capacity, which has greatly improved the effluent, water quality and volume load of MBR membrane bio-reactor, and the water quality standard after membrane treatment is high (more than national level A Standard). After disinfection, high-quality reclaimed water with high water quality and biological safety can be formed, which can be directly used as a source of fresh water. Due to the filtration function of the membrane, the microorganisms were completely trapped in the MBR membrane bio-reactor, which completely separated the activated sludge age during the hydraulic retention period and eliminated the sludge swelling problem in the traditional activated sludge process. MBR membrane bioreactor has a lot of advantages, such as high removal efficiency of pollutants and strong nitrification ability. It can simultaneously perform nitrification, denitrification, good denitrification effect, stable effluent water quality, low residual sludge production, compact equipment, and small footprint (only traditional (1 / 3-1 / 2 of the process), convenient incremental expansion, high degree of automation, simple operation, etc.

Operation Principle

The membrane bioreactor (MBR) process is a new type of wastewater treatment technology that organically combines membrane separation technology and biotechnology. It uses membrane separation equipment to capture activated sludge and macromolecular organic substances in the biochemical reaction tank, eliminating the need for a secondary sedimentation tank. Therefore, the activated sludge concentration is greatly increased, and the hydraulic retention time (HRT) and the sludge retention time (SRT) can be controlled separately, and the refractory substances are continuously reacted and degraded in the reactor.

Therefore, the membrane bioreactor (MBR) process 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.

Its basic structure is shown in the following figure:

Equipment performance parameters

The core component of MBR integrated equipment is a membrane bioreactor, and its inlet water quality requirements are as follows:

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

The effluent Water Quality

The effluent water quality meets the standard of miscellaneous domestic water:

Typical process flow

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

This technology is an advanced wastewater treatment technology. Its core is based on the immersion type reinforced hollow fiber membrane separation and biological reaction technology. It integrates a suspension growth bio-reactor with an ultrafiltration membrane separation system and replaces it with an ultrafiltration membrane separation method. Secondary sedimentation tank and sand filtration system in traditional activated sludge treatment system. Its characteristics are very good treated water quality, suspended solids, CODcr, NH3-N, BOD5 and turbidity are very low, can be directly reused as miscellaneous water, such as domestic miscellaneous water other than drinking water, garden greening, car washing, etc .; industrial water , Such as circulating cooling water or directly used as reverse osmosis inlet water, production boiler make-up water and electronics industry ultra-pure water.

The ultrafiltration membrane is usually directly immersed in the aeration tank and directly in contact with the biological reaction mixture. The filtered water is passed through the external pressure type hollow fiber membrane to achieve solid-liquid separation through the negative pressure suction of the filter pump. The differential pressure of negative pressure suction is very low, with a maximum head of only 2.2 meters, and the energy required to process water is small. During the filtration process, air is blown into the bottom of the membrane by a blower. On the one hand, the turbulence caused by the rising airflow has a scrubbing effect on the outer surface of the hollow fiber membrane, which can continuously remove the solid substances attached to the surface of the membrane to prevent or reduce membrane pollution or blockage; on the other hand, this airflow also has Aeration can provide most of the oxygen consumption required for biodegradation. The rest of the oxygen required for biodegradation is also done by a diffusion aeration system. Excess sludge produced in the biological reaction is directly discharged from the ultrafiltration membrane tank.

Main Advantages

MBR membrane bioreactor has the following outstanding advantages in the application of MBR sewage treatment and MBR water reuse project:

1) MBR has high pollutant removal efficiency and good effluent quality
2) MBR has high sludge concentration, large device volume load and small footprint
3) MBR is conducive to slow proliferation or high-efficiency microorganism retention, improve the nitrification effect of the system and the ability to treat difficult-to-degrade organic matter
4) MBR membrane bioreactor has low residual sludge production
5) MBR membrane bioreactor is easy to realize automatic control and convenient operation and management
6) After treatment, the SS and turbidity of the discharged water are close to zero, which can be reused.

MBR Process Characteristics

1) Degradation of organic matter in sewage, nitrifying bacteria nitrate NH3-N to NO3-, the removal rate of organic matter is more than 95%; the removal rate of ammonia nitrogen is more than 97%.
2) The pretreatment process is simple, no large amount of chemical agent is needed, and the operation process is simple
3) High recovery rate, the water recovery rate can reach more than 99%. This flexibility allows the operator to reduce the “pressure” on the diaphragm by reducing the recovery rate when the quality of the incoming unpurified water deteriorates, but at the same time produces the same total amount And quality purified water
4) The system uses a logical process monitoring system, including flow transmitters and pressure transmitters. This highly controlled system approach can be used to design the most flexible systems and increase the minimum requirements for operator interfaces
5) Air flushing guarantees reliable operation under various inflow conditions
6)  Automatic backflushing guarantees to increase the overall membrane flux at lower membrane pressure
7) Small area, only 10-20% of traditional craftsmanship
8) Long service life, continuous running time can reach 70,000 hours, and the broken wire rate is less than 1%.