The MBR tank uses membranes to filter the mud-containing sewage in the biochemical reaction tank to achieve mud-water separation. On one hand, the membrane trapped microorganisms in the reaction tank, which greatly increased the concentration of activated sludge in the tank to a very high level, and made the biochemical reaction of degrading sewage proceed faster and more thoroughly; on the other hand, due to the high filtration precision of the membrane, the effluent is guaranteed to be clear and transparent, and high-quality product water can be obtained.
So what should we pay attention to during the MBR process?
The temperature of the sewage will change with the temperature, and the inoculation sludge can be put into proper use, and the lower operating load can be controlled. When the temperature of the raw sewage is less than 12℃, the nitrification of the biochemical system will decrease, and the effluent ammonia nitrogen index of the MBR Membrane System may exceed the standard.
In the initial stage of sludge cultivation, since the sludge has not yet formed in large quantities, the flocculation performance of the produced sludge is not very good, and it is still in a discrete state. In addition, the concentration of sludge is low, and the microorganisms are easy to be in the state of endogenous respiration, so the amount of aeration cannot be too large. It can be controlled at about 1/2 of the design normal value. Otherwise, flocculent sludge is not easy to form.
(3) Monitoring and inspection
During the sludge cultivation process, not only the SV and MLSS of the aeration tank mixture should be observed, but also the biological phase of the sludge should be observed at any time to understand the growth of the bacterial micelles and indicator microorganisms, so as to make necessary adjustments to the cultivation process according to the situation.
(4) Control of return sludge volume
The control of the return sludge system adopts a constant return ratio. When the inflow sewage volume changes, the return sludge volume is adjusted accordingly. Using this method, when the remaining sludge discharge volume is basically unchanged, the MLSS, F/M and the mud level in the aeration tank can be kept basically constant, without changing with the change of the inflow sewage volume Q, so as to ensure a relatively stable treatment effect.
(5) Control of excess sludge discharge
Due to the MBR process, the incoming water quality is better and the amount of mud produced is less. With the stable operation of the system, the amount of sludge in the system will gradually increase, and the sludge concentration needs to be adjusted according to the process adjustment requirements. The amount of sludge discharged daily and the time of sludge discharge are closely related to the concentration of influent pollutants and the amount of influent water, which should be carried out after process analysis.
MBR Membrane Bioreactors are used more and more widely in wastewater treatment plants, but the operational problems brought by them have gradually become prominent. As a wastewater treatment plant that adopts MBR process, it is necessary to combine the actual working conditions of activated sludge to have an in-depth understanding and mastery of MBR membrane bioreactor, and adopt reasonable process and operation and management measures to ensure the stable operation of the MBR process.