NIRE-170-1-6
36
minute to make certain sufficient sludge mixing has taken place prior to restarting the
filtration process. The suction pump should always be off when performing air diffuser
cleaning.
(2)
Membrane scouring blower
: The blower supplying air for membrane scouring should be
on continuously. Air flow (and suction pump) should be stopped if the liquid level in the
membrane tank falls below the preset low level for a long period or flow to the membrane
tank stops. In such cases the air supply should be applied for five (5) minutes each hour
the system is not producing filtrate. This is required to keep the sludge well mixed and in
good condition for restarting the filtration process while avoiding too much stress to the
membrane elements.
(3)
Membrane tank water level
: If the liquid level in the membrane tank reaches the low
level, the suction pump and membrane scouring air should be stopped. If the membrane
tank reaches high level the wastewater feed supply should be stopped.
(4)
TMP
: Two TMP alarms should be incorporated into the M
BR control logic. A ”HIGH TMP
ALARM” should be activated when the TMP increases 5 kPa from the initial TMP value.
A ”HIGH HIGH TMP ALARM” which stops filtration should be activated when the TMP
reaches 20 kPa.
(5)
Air diffuser cleaning valves
: It is recommended that the air diffuser valves, fitted with
automatic actuated valves, be installed to facilitate automatically controlled operation of
the air diffuser cleaning cycles. Air diffuser cleaning should take place at least one time
per 24 hour period of operation.
(6) Equalizing/balancing wastewater load in terms of both quality and quantity is quite
important for stable operation of MBR. In this regard having equalization tank with mixing
equipment is recommended.
