Cleaning The Diffuser - Mitsubishi STERAPORE 5600 FF Series Instruction Manual

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Cleaning the Diffuser

The FB diffusers embedded in the module are SUS perforated pipe diffusers. When SUS perforated pipe
diffusers are used for long periods of time, sludge may enter the diffusers, dry, and block the holes. Therefore
they must be cleaned regularly to stop the sludge from drying.
The diffuser cleaning process is composed of two processes, feeding and discharging. In the feeding process,
air supply from the permeate pump and blower to the diffuser is stopped, and the MV automatic valve in the
branch line installed in the pipe is opened, which allows water in the tank to flow into the diffuser. In the
discharging process, the MV automatic valve is closed, the air supply is restored and the tank water in the
diffuser is discharged.
Clean diffusers once every 1 to 6 hours with the inflow time kept to around 1 minute. When air supply is
resumed by closing the MV automatic valve in the branch line, sludge will be discharged within approximately
10 seconds and aeration will be resumed. Resume filtration after aeration has resumed. As the time it takes to
resume aeration after the blower starts up depends on piping and the blower's capacity, configure a delay
timer or similar accordingly to cover the time between the blower starting and the permeate pump starting.
Make sure that the diffuser cleaning operation is automatic.
As diffusers tend to clog if sludge is very concentrated and/or viscous, adjust the cleaning frequency and
inflow time accordingly. Sometimes, they may have to be set to values higher than those stated above.
If the diffuser is clogged, stop filtration and clean the diffuser. If the clogging is light, clean the diffuser normally
several times consecutively or feed clean water into the diffuser. If the diffuser is badly clogged, remove it
from the tank and clean it.
 Diffuser cleaning method (example)
1. Suspend air supply to the diffuser.
Stop the blower. To clean individual blowers when a group of multiple blowers is used to supply air,
install automatic valves in branch pipes and close them.
2. Open the automatic valve in the exhaust line, to allow air in the pipes to be discharged into
the atmosphere and sludge to flow in.
Pay attention to noise caused by air discharging. Use a manometer to confirm that enough air has
been discharged.
3. Restart suction.
After 1 minute, start up the blower, and after a further 30 seconds, start up the permeate pump.
STERAPORE 5600 Series (FF) Instruction Manual
Figure 2-2 Feeding Tank Water for Diffuser Cleaning
Chapter 2 Filtration and Membrane Scour Aeration
Install an exhaust line and an automatic
valve in the pipe between the blower and
the diffuser.
Let tank water flow into the diffuser by
suspending the supply of air to the diffuser,
opening the automatic valve, and releasing
pressure.
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