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4. Daily Inspection
For the operating parameters listed in the preceding section, perform inspection periodically,
at least once per week, as follows. Please check trends of these data and take necessary
actions before too late.
(1) Trans-membrane pressure
Please check that the trans-membrane pressure is stable. Please carry out chemical
cleaning before the trans-membrane pressure increase by 5 kPa (50 mbar) from its initial
operating level at the same permeated water flow rate. Sudden increase in the
trans-membrane pressure suggests the membrane clogging caused by abnormal diffused air
condition, too high flux, concentration of the sludge in membrane submerged tank or
deteriorating sludge properties. In such an event, check the operating condition and
biological condition and take necessary actions and carry out chemical cleaning of the
elements.
(2) Diffused air conditions
Please check that the fixed amount of air within the standard range is supplied from the
diffuser by checking air flow-meter and pressure gage of the air supply line. Also, check that
the air is diffused evenly within one module and also evenly among modules. Deviation in the
scouring air flow rate from the standard intensity may cause the membrane clogging in the
weak zone and element damage in the strong zone. 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 adjusting the scouring air flow rate.
If extraordinary uneven
diffusion still continues, conduct the air diffuser inspection and cleaning procedure described
in Section 2, Chapter VIII.
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) Activated sludge characteristics
The activated sludge of the membrane bioreactor should be self-cohesive and free from odor.
The color of the activated sludge is typically brown, however differs among plants, depending
on wastewater component, organic load and so on. If unexpected change is observed in
CAUTION
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