Views:1326 Author:Kevin Chen Publish Time: 2020-07-15 Origin:Site
1. The requirements for source water
The inlet water of MBR must be treated by the front-end biochemical treatment system, being activated by sludge inoculation / breeding and debugging. After the end water quality has reached the biochemical treatment effect, it is suitable to start entering the membranebio-reactor for mud-water separation. If the source water is directly separated by the membranes may cause membrane clogging earlier.
In order to maintain the good processing capacity of the membrane bio-reactor, it is necessary to ensure that the processing conditions such as MLSS concentration, viscosity, DO (dissolvedoxygen), and pH in the membrane bio-reactor are in a proper range.
If the source water contains many inclusions or coarse SS (suspended matter), and if the specific gravity of the oil component is large, appropriate pre-treatment is needed.
●Oil content — Oil content will cause the surface of the membrane to clogged. Generally, animal and vegetable oils should be controlled below 50mg/L, and mineral oils should be controlled below 3 mg/L. When the water content exceeds the standard, corresponding treatment equipment should be considered.
●When the mbr is operated in aeration, if a large amount of bubble is generated, the design should consider spraying and defoaming with a defoamer. Please use a high-grade ethanol-based defoamer. Silicon-based defoamers can easily cause membrane fiber clogging.
●If the BOD load is operated under a high load condition, the fiber will easily cause clogging. Please adjust to a suitable load. The BOD sludge load is 0.05 ～ 0.15 (kg-BOD/kg activated sludge·d) (the standard valueis0.07)
2. Operation Management
The operating performance of the membrane tank changes with the quality of the source water and the set operating conditions. In order to maintain stable operation of the membrane tank, it is recommended that the user manage and record various operating data to ensure that the user monitors the changes and characteristics of the operating performance of the membrane tank.
A. The aeration volume of the biochemical system
B. The aeration status and the amount of the membrane
C. Water temperature
D. The pH of MBR tank
E. DO (dissolved oxygen concentration)
G. Transmembrane pressure difference (TMP) during operation
H. Production water quality (BOD, COD, turbidity, etc.)
I. Source water quality (BOD, COD, suspended matter, etc.)
J. The amount of excess sludge discharge
K. Sludge concentration
L. Sludge sedimentation performance (SV30)
M. Sludge viscosity
3. Description of the operational monitoring
(1)Transmembrane pressure difference(TMP)
Check the stability of TMP.
The sudden rise of the TMP indicates the occurrence of membrane clogging, which maybe caused by abnormal aeration or excessive sludge concentration. It is necessary to investigate the cause in time and take corresponding measures.
Check regularly, to see if the aeration volume of the membrane module is in the required range and whether it is uniformly aerated. When the aeration air volume is abnormal or the aeration is nonuniform, necessary measures need to be taken.
When the aeration is insufficient or the aeration is stopped, the suction operation must not be performed, otherwise, the membrane surface will be blocked.
For example, check the installation, check the blower, or adjust the aeration.
(3) The flow of the production water
Record the daily production water amount and flow rate changes. The backwash frequency and cleaning scheme of the MBR can be adjusted according to the flow rate decay and the water production rate changes.
(4) Sludge concentration
The MLSS of membrane bio-reactor is around 4-15g/L.
Appropriate MLSS concentration can ensure the quality of the effluent water that meets the design requirements.
When the MLSS is too low, the measures such as putting in sludge or stopping sludge return or discharge can be adopted.
When the MLSS is too high, measures such as increasing sludge return or discharge can be taken.
(5) Sludge viscosity
Normal sludge should be below 100mPa·s. If this condition is not met, the performance may not be achieved, so please adjust to the normal viscosity range. When it is too high, you can take measures such as renewing sludge, increasing sludge return or discharge.
(6) DO (dissolved oxygen concentration)
The normal DO at the end of the membrane bioreactor is 2mg/L ～ 3mg/L. When this condition is not met, measures like adjusting the aeration amount can be taken.
The PH in the membrane bioreactor is 6-8. When this condition is not met, the pH of source water can be adjusted by adding Acid or Alkali.
(8) Water temperature
The normal water temperature is 15-35°C. Where this condition is not met, necessary measures such as cooling and thermal insulation can be taken.
(9) Water level
Check the water level of the membrane bio-reactor to ensure that the minimum water level can submerge the membrane module. When an abnormality occurs, please check the following in time:
A. Check whether the liquid level meter is normal.
B. Whether the membrane water outlet pipe is flowing or leaking.