TORAY MBR
Instruction Manual
06-G-MB2-NHPAF-220801
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9. Storing Products after Use
Take the following steps to preserve and store used “NHPA Series” modules.
(1) In case of module storage with sludge inside (without sludge drainage), stop
filtration and aeration should be stopped or intermittent e.g. five (5) minutes every
hour to agitate and supply minimal DO to the sludge.
Continuous aeration should not be applied from the viewpoint of membrane protection.
Also, open air discharge valve on filtrate piping during aeration to avoid the possible air
accumulation inside module and subsequent module damage.
(2) For long-term storage of used module (i.e. just for membrane preservation), take
following steps.
•
Drain the sludge in the membrane tank.
•
Using a water hose, wash off the sludge from the modules with clean water. In
addition, wash off any remaining sludge on the tank walls. Never use a pressure
washer machine on the membrane module and element.
•
Fill the membrane tank with clean water until the module is completely covered.
Periodically check the water level and add more water if needed to keep the module
covered with water. Open air discharge valve before pouring water and keep it open
during storage.
•
A periodic dosing of the membrane tank storage water to a < 50 ppm concentration
of sodium hypochlorite will help inhibit the growth of algae/microorganism during the
storage period. Maintaining a hypochlorite concentration higher than 50 ppm for a
long-time interval could cause damage to stainless steel components.
•
If aeration is required during long-term storage, the aeration cycle should be
controlled to aerate only five (5) minutes every hour.
(3) Before re-commissioning of the modules, it is strongly recommended conducting
a chemical cleaning of the modules to remove any biofilm growth that may have
developed on the membrane surface and piping during the storage period.
If used module (after washing off sludge) must be kept out of water, its duration should be
limited within 24 hours and periodic sprinkling of water on the modules (especially membrane
surfaces) is needed. In that case, it is required to cover the module (especially top and sides)
with a tarp or some other plastic sheet that will protect the module from dust, wind, and direct
sunlight.
Never use a pressure washer machine when washing the
membrane module and element which can cause fatal
delamination of membrane element edge.
CAUTION
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