GIRE-097-2-2
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c. Check the control devices work well during the clean water operation.
d. Start filtration with clean water. Measure and record the trans-membrane pressure
and water temperature at designed filtration rates (at a normal, maximum and
minimum flow rate). Maintain such records.
e. Stop the filtration and the air supply as soon as the above tests finish.
Don't conduct clean water operation for a long time. Clean water
operation tends to cause membrane clogging.
Keep the membrane wet once it gets wet with clean water
operation. If those membranes get dried up, the permeability may
be decreased seriously.
2. Seeding Sludge Injection
The membrane may get clogged seriously if you filter the wastewater without activated
sludge, so don't fail to seed sludge before starting filtration.
Please inject the seeding sludge to the membrane submerged tank with the following steps:
(1)
Transport fresh and healthy activated sludge from the other wastewater treatment
plant treating the same kind of wastewater. Activated sludge with higher MLSS
concentration and higher MLVSS/MLSS ratio is preferable. Initial MLSS
concentration of the membrane submerged tank shall be preferably 7,000 mg/L or
higher, at least 3,000 mg/L.
(2)
Supply the seed sludge through the screen to the tank.
(3)
Please start feeding the raw wastewater soon after the sludge injection.
(4) Do not use seeding agents.
(5)
Do not use silica-based anti-foam agent in case of foaming.
Remove foreign matters from the seeding sludge with the mesh
screen which opening is 3.0 mm or under before injection.
3. Actual Filtration Operation
Following the seeding sludge injection, please start the air diffusion, the filtration and the raw
wastewater feed.
Attention needs to be paid to this start-up operation such as:
(1)
Start filtration with much lower flux than design value, especially when seeding
CAUTION
!
CAUTION
!
CAUTION
!