Mitsubishi STERAPORE 5600 FF Series Instruction Manual page 22

3-1-3 Precautions Regarding Chemical Cleaning
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Handling Chemicals
Chemicals such as NaClO, and oxalic, citric, sulfuric, and hydrochloric acid are used in chemical
cleaning.
C AUT IO N
Wear safety goggles and protective gloves and handle chemicals appropriately with due
consideration for the environment and safety by referring to SDS and other relevant
information.
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Countermeasures Against Raw Water Inflow During Chemical Cleaning
Raw water inflow during chemical cleaning, particularly chemical soak cleaning, temporarily disables or
impedes processing. Implement appropriate measures in accordance with the state of equipment to
prevent raw water from overflowing.
Example measures are shown below. Each of the following measures can be implemented individually
or in combination with others.
 If there is a flow equalization tank, set the water level of the flow equalization tank to the minimum
before cleaning.
 If multiple modules or lines of modules are operated, clean them in several batches.
 It is also possible to adjust the flux through an operating module to control the total treatment flow.
 Restrict raw water inflow if possible, e.g. in a factory, etc.
 Perform cleaning when the raw water inflow is low (for instance, on Saturday, Sunday or at night).
C AUT IO N
If raw water inflow is expected to increase due to rain or other reasons, finish cleaning before it
increases or postpone cleaning.
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Residual Free Chlorine in Membrane Treated Water After Maintenance Cleaning
 Some of the NaClO used in maintenance cleaning is discharged into the membrane tank. Residual
chlorine discharged is deactivated by sludge under the conditions stated in this manual. Therefore it
does not affect biological processes or the quality of treated water.
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Residual Free Chlorine and Acid in Membrane Treated Water after Recovery Cleaning
 Some of the chemical solution used in recovery cleaning is discharged into the membrane tank.
Residual chlorine discharged is deactivated by sludge under the conditions stated in this manual.
Therefore it basically does not have much effect on biological processes. Residual acid may
sometimes lower the pH in the tank, but it also basically does not have much effect on biological
processes.
 Chemical solutions that remain in the system are discharged with treated water when the filtration
process starts. Therefore they may temporarily affect the properties of the treated water. Although
the concentration of chemicals declines sharply as filtration progresses, the effluent quality may
cause problems with discharge water quality control. If necessary, take the following measures.
・Adjust the pH levels
・Return the first cycle to the equalization tank or similar and reprocess it
・Process the first cycle as waste chemicals (as the amount of waste chemicals differs according
to the treatment volume of the facility and the state of piping it must be calculated individually)
STERAPORE 5600 Series (FF) Instruction Manual
Chapter 3 Chemical Cleaning
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