Mitsubishi STERAPORE 5700 Series Instruction Manual page 13

2-1-3 Permeate Pumps
Determine the pump specifications on the basis of flow rate, pump location, actual pump head, pipe
resistance, and so on.
RE F ER E NC E
 Choosing a self-suction pump as the permeate pump makes it easy to maintain suction pressure
during intermittent filtration operation. Furthermore, air in pipes can be easily discharged if
operation is resumed after being stopped for chemical cleaning or similar. It is possible to select
an ejector, vacuum pump or other equipment that removes air from pipes instead of a self-suction
pipe.
 Trans membrane pressure
*
The difference between the pressure during filtration and the pressure during relaxation.
 Constant rate filtration is conducted by installing a constant flow valve on the discharge side of the
permeate pump or controlling the permeate pump inverter.
 Set the alarm pressure and the abnormal stop pressure for the permeate pump. If the alarm pressure
is exceeded, perform chemical cleaning immediately. The alarm and abnormal stop pressures may
be set at values considered to be appropriate.
C AUT IO N
Depending on how the permeate pump and pipes are installed, air pockets that prevent stable
operation of the product can occur in pipes. Deaeration equipment may be required, particularly
when using large diameter pipes. For small scale facilities, it is also possible to prevent air
pockets by locating the permeate pump at the highest position in the water treatment line.
2-1-4 Configuring Intermittent Filtration Settings
Relaxation time, in which membrane surface cleaning is conducted, must be provided between suction
intervals for stable treatment using the MBR system. Conduct intermittent filtration at the following
interval.
Filtration time: 7 minutes or less
Relaxation time: 1 minute or longer
C AUT IO N
Consecutive filtration with no relaxation time may result in sludge floc and fine particles being
deposited onto and adhering to the membrane surface, making continued operation difficult.
Make sure that relaxation time is provided.
In the filtration process, continue aeration even during relaxation time. Only suspend aeration
during diffuser and chemical cleaning.
STERAPORE 5700 Series (FF) Instruction Manual
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is normally around -5 to -30 kPa in MBR systems.
Figure 2-1 Conceptual Diagram of Membrane Cleaning
Chapter 2 Filtration and Membrane Scour Aeration
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