MBR, also known as membrane bioreactor, is a new type of water treatment technology that combines a membrane separation unit and a biological treatment unit. According to the structure of the membrane, it can be divided into flat membrane, tubular membrane and hollow fiber membrane. According to the membrane pore size, it can be divided into ultrafiltration membrane, microfiltration membrane, etc. In the process of operation and management of the device, the maintenance and management of MBR Membrane Modules are extremely important and directly determine the effect of sewage treatment.
1. Concentration and Activity of Sludge
Under normal circumstances, keep the activated sludge concentration (MLSS) running in the MBR tank at about 3000-6000mg/l. Excessive sludge concentration will cause the suction pressure to rise and the degradation rate of microorganisms will also decrease, making the effluent quality worse. However, if the activated sludge concentration is too low, the pollutants in the water body will pollute the membrane module faster. Therefore, the MBR tank must ensure that the sludge concentration and activity in the tank are under normal or relatively stable conditions before the suction pump can begin to suck the effluent.
2. Sufficient Aeration Volume and Operation Stability
We must ensure that the membrane module has sufficient aeration to wash the surface to reduce the gel thickness on the membrane module surface. In addition, a tail gas discharge pipe should be installed on the aeration pipe of the membrane frame, and it should be manually opened for discharge treatment regularly, so that the aeration pipe is washed back and forth by liquid, so as to ensure that the pipe is not blocked by sludge. What’s more, the stability of the operating state of the system should also be ensured, so a suitable regulating tank lift pump (anoxic tank lift pump) should be selected to achieve high filtration efficiency.
3. Cleaning of MBR Membrane Module and Control of Oil Content in Water
The water output of the membrane module should be within the design range and controlled by a flow meter or suction pressure. When the membrane module is contaminated, the membrane module in the module needs to be chemically cleaned online. Moreover, the oil content in the water should be strictly controlled. The oil will adhere to the membrane surface and affect the membrane’s water flux. When the oil content in the measured water body is greater than the design oil content value, an oil separator should be added before the sewage enters the grid well.
4. Inlet Water Quality and Minimum Level Protection
The influent water of the MBR pool shall not contain the dissolution of polymer coagulant, epoxy resin and ion exchange resin. Therefore, these substances must be removed before entering the MBR tank, otherwise they will form chemical fouling on the surface of the membrane module, which will reduce the membrane flux of the MBR membrane and can not be restored.
5. PH Value and Temperature Control
The raw water should be tested for PH before entering the MBR pool to control it between 5-9. If the PH exceeds this range, add acid or alkali for debugging until the PH value remains between 5-9 to avoid irreversible damage to the MBR membrane module. In order to extend the service life of the MBR membrane module and reduce the cost of filtration, the temperature of the water during use should be controlled between 5-45℃.
During the operation of the MBR membrane module, the maintenance plan of the MBR membrane module is formulated according to the actual situation of the project site and the above mentioned points, so that the MBR membrane module can operate efficiently in sewage treatment, and finally achieve the effect of high filtration efficiency and low cost.