The influence of the operation control parameters of membrane bioreactor on the operation effect

The operating conditions of membrane separation mainly include operating pressure, membrane surface flow rate and operating temperature
.
The main controlling parameters sludge concentration, organic load, SRT, DO, pH, temperature and the like

For pressure, it is generally believed that there is a critical pressure value
.
When the operating pressure is lower than the critical pressure, the membrane permeability increases with the increase of pressure; when it is higher than this value, the membrane surface pollution will increase, and the permeability will not change much with pressure

The increase of the membrane surface flow rate can increase the degree of water flow disturbance on the membrane surface, improve the accumulation of pollutants on the membrane surface, and increase the membrane permeability
.
The degree of influence varies according to the size of the membrane surface velocity and the state of the water flow (laminar or turbulent)

Increasing the temperature is beneficial to the filtration and separation process of the membrane
.
The test results of Magara and ltoh show that a temperature increase of 1℃ can cause a 2% change in membrane permeability

Regarding the sludge concentration, many research results show that the higher the sludge concentration under certain conditions, the lower the membrane flux; in aerobic MBR, the increase in organic load has no significant effect on the effluent quality; in anaerobic MBR, the The sludge concentration increases slowly with the increase of organic load, so the effluent water quality is easily affected by organic load
.

The impact of sludge age on the sludge characteristics and membrane fouling of membrane bioreactors.
Some literature points out that the change of SRT in MBR is the root cause of the changes in the characteristics of the sludge mixture.
The effect of SRT on the total and compactness of extracellular polymer (EPS) is The content of adherent extracellular polymer (TB) and loosely attached extracellular polymer (LB) and the ratio of protein to polysaccharide in it have an important influence, which affects the physical, chemical and biological characteristics of the sludge mixture, and comprehensive consideration of membrane fouling Resistance and sludge characteristics, the sludge age of the membrane bioreactor should be controlled below 120 times the minimum generation time of the dominant bacteria
.

The change of aeration volume does not have much impact on COD removal, which means that under the conditions of low aeration volume and high aeration volume, the organic carbon source can be biodegraded by oxygen and nitrate as electron acceptors
.
Short-term hypoxia can also achieve good water effluent effects, but the odor of water is too long