MBR , also known as membrane bioreactor, is a process that combines biological treatment with membrane technology. Tubular MBR technology uses an external tubular ultrafiltration membrane as the membrane separation device, offering advantages such as high membrane flux ( 5-10 times that of submerged membranes) , strong anti - fouling ability, high sludge concentration ( 2-4 times that of submerged membranes and 3-5 times that of traditional activated sludge processes ), and long membrane life ( 3-5 years ). It is currently widely used in leachate treatment both domestically and internationally. Tubular MBR offers the following advantages for leachate treatment:
Hydraulic retention time and sediment age separation
Membrane technology can completely retain microorganisms in the water, achieving separation of hydraulic retention time and sludge age. This makes operation and control more flexible and allows for extended sludge age, which is beneficial for the growth and reproduction of slow-growing nitrifying bacteria, greatly improving denitrification efficiency. At the same time, due to the long sludge age of the system, the amount of residual sludge produced is very small.
The quality of the effluent is higher than that of traditional biological processes.
Membrane technology can not only retain microorganisms in water, but also some large-molecule insoluble pollutants, prolonging the residence time of pollutants in the reactor and increasing the removal rate of recalcitrant pollutants. At the same time, due to the long sludge age and good denitrification effect, plus the fact that the effluent is basically free of SS , the effluent quality of MBR is better than that of traditional processes.
Small footprint
Due to the high retention rate of the membrane system, a high sludge concentration can be maintained in the reactor, which is usually 3 to 5 times that of the traditional activated sludge process. The high sludge concentration makes the reactor volume much smaller than that of the traditional process. In addition, the high-efficiency deep-water oxygen supply method makes the biological part occupy a much smaller area than the traditional process.
High impact resistance
The high sludge concentration also improves the system's resistance to shock loads.
It can effectively reduce pollutant concentrations
MBR , as a biochemical treatment process, can convert organic matter into carbon dioxide and water, nitrogen pollutants into nitrogen gas, and reduce the conductivity of raw water. This greatly reduces the load on subsequent membrane treatment processes, extends membrane life, increases water production rate, and reduces concentrate concentration.
Of course, MBR , as a biochemical process, also has the disadvantages of other biochemical processes:
The treatment effect depends on the biodegradability of the leachate.
Since MBR mainly relies on the biological stage to remove pollutants, its treatment effect is highly dependent on the biodegradability of the leachate, and it is not suitable for mid-to-late stage leachate with poor biodegradability.
Many influencing factors
Many factors influence effluent quality. Seasonal changes, variations in waste composition, landfill age, weather conditions, and human activities can all alter the quality and quantity of landfill leachate, creating shock loads on the system and consequently affecting effluent quality. Furthermore, improper control of system parameters such as load, temperature, pH , alkalinity, dissolved oxygen (DO) , and sludge age can also negatively impact effluent quality.
The effluent cannot meet the high standards.
Landfill leachate contains a large number of non-biodegradable pollutants that cannot be removed by biological methods. The COD concentration and color value of the effluent from MBR are still relatively high. This means that MBR treatment of leachate effluent cannot meet high discharge standards. To meet high effluent standards, membrane technology or other physical methods with higher removal efficiency are required.
High energy consumption
Tubular MBRs require high-flow-rate, high-lift circulating pumps to provide power, creating high-speed scouring on the membrane surface to prevent membrane fouling, increase permeate flux, and enhance cleaning effectiveness. However, this also results in high power consumption for tubular MBRs .
MBR , also known as membrane bioreactor, is a process that combines biological treatment with membrane technology. Tubular MBR technology uses an external tubular ultrafiltration membrane as the membrane separation device, offering advantages such as high membrane flux ( 5-10 times that of submerged membranes) , strong anti - fouling ability, high sludge concentration ( 2-4 times that of submerged membranes and 3-5 times that of traditional activated sludge processes ), and long membrane life ( 3-5 years ). It is currently widely used in leachate treatment both domestically and internationally. Tubular MBR offers the following advantages for leachate treatment:
Hydraulic retention time and sediment age separation
Membrane technology can completely retain microorganisms in the water, achieving separation of hydraulic retention time and sludge age. This makes operation and control more flexible and allows for extended sludge age, which is beneficial for the growth and reproduction of slow-growing nitrifying bacteria, greatly improving denitrification efficiency. At the same time, due to the long sludge age of the system, the amount of residual sludge produced is very small.
The quality of the effluent is higher than that of traditional biological processes.
Membrane technology can not only retain microorganisms in water, but also some large-molecule insoluble pollutants, prolonging the residence time of pollutants in the reactor and increasing the removal rate of recalcitrant pollutants. At the same time, due to the long sludge age and good denitrification effect, plus the fact that the effluent is basically free of SS , the effluent quality of MBR is better than that of traditional processes.
Small footprint
Due to the high retention rate of the membrane system, a high sludge concentration can be maintained in the reactor, which is usually 3 to 5 times that of the traditional activated sludge process. The high sludge concentration makes the reactor volume much smaller than that of the traditional process. In addition, the high-efficiency deep-water oxygen supply method makes the biological part occupy a much smaller area than the traditional process.
High impact resistance
The high sludge concentration also improves the system's resistance to shock loads.
It can effectively reduce pollutant concentrations
MBR , as a biochemical treatment process, can convert organic matter into carbon dioxide and water, nitrogen pollutants into nitrogen gas, and reduce the conductivity of raw water. This greatly reduces the load on subsequent membrane treatment processes, extends membrane life, increases water production rate, and reduces concentrate concentration.
Of course, MBR , as a biochemical process, also has the disadvantages of other biochemical processes:
The treatment effect depends on the biodegradability of the leachate.
Since MBR mainly relies on the biological stage to remove pollutants, its treatment effect is highly dependent on the biodegradability of the leachate, and it is not suitable for mid-to-late stage leachate with poor biodegradability.
Many influencing factors
Many factors influence effluent quality. Seasonal changes, variations in waste composition, landfill age, weather conditions, and human activities can all alter the quality and quantity of landfill leachate, creating shock loads on the system and consequently affecting effluent quality. Furthermore, improper control of system parameters such as load, temperature, pH , alkalinity, dissolved oxygen (DO) , and sludge age can also negatively impact effluent quality.
The effluent cannot meet the high standards.
Landfill leachate contains a large number of non-biodegradable pollutants that cannot be removed by biological methods. The COD concentration and color value of the effluent from MBR are still relatively high. This means that MBR treatment of leachate effluent cannot meet high discharge standards. To meet high effluent standards, membrane technology or other physical methods with higher removal efficiency are required.
High energy consumption
Tubular MBRs require high-flow-rate, high-lift circulating pumps to provide power, creating high-speed scouring on the membrane surface to prevent membrane fouling, increase permeate flux, and enhance cleaning effectiveness. However, this also results in high power consumption for tubular MBRs .
