AIRE-064-1-4
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3. Daily
Inspection
There are three key items for the stable operation without troubles, those are the
trans-membrane pressure, the diffused air conditions and the biological treatment situation.
For the control parameters listed in the preceding section, perform inspection as follows:
(1) Trans-membrane
pressure
Please check that the trans-membrane pressure is stable. A sudden increase in the
trans-membrane pressure suggests the membrane clogging, caused by abnormal diffused
air condition or deteriorating sludge properties. In such an event, check the following items
and take necessary actions, such as chemical cleaning of the elements.
(2) Diffused
air
conditions
Please check that the fixed amount of diffused air is supplied and that the air is diffused evenly in
the module. Deviation in the scouring air flow rate from the fixed value or uneven diffusion may
cause the membrane clogging. So in such a case, stop filtration, and check the leakage from the
piping, valve situation and the blower condition. If necessary, take appropriate actions, such as fix
the leakage, correct valve situation, adjust the blower condition and adjust the scouring air flow
rate.
If the scouring air flow rate drops or becomes extremely irregular or
if air supply is stopped, then immediately stop filtration to prevent
membrane clogging.
(3) Color and smell of activated sludge
In general, the activated sludge suitable for the wastewater treatment should be
brownish-red, coagulable and free from odor. If the sludge appears failing to meet these
requirements, then measure its MLSS, viscosity, DO, pH, temperature and BOD load. Please
take appropriate actions, such as additional injection of seeding sludge, if necessary.
(4) MLSS
MLSS in the membrane submerged tank is normally 7,000 to 18,000 mg/L. If MLSS is too
low, please add seeding sludge or stop excess sludge discharge. If MLSS is too high, please
increase excess sludge discharge to the sludge storage tank.
(5) Sludge
viscosity
It is desirable that the sludge viscosity is not higher than 250 mPa
・
s. If the sludge viscosity
CAUTION
!
