A solution of 0.1% sodium
hydroxide (NaOH) and 0.1% of
tetra-sodium salt of ethylene
diamine tetraacetic acid (Na-
EDTA)
A solution of 0.1% sodium
hydroxide (NaOH) and 0.05%
sodium salt of dodecyl-sulfate
(Na-DDS),
A solution of 1.0% sodium
triphosphate (STP) and 1.0%
trisodium phosphate (TSP) and
1.0% Na-EDTA.
The pH of the solution should be
approximately 11 - 12. The
temperature of the solution should
not exceed 86°F (30°C).
MEMBRANE CLEANING
DIRECTIONS
These directions describe how the
membranes can be cleaned using
the EPRO system. If a cleaning
station is used, please follow the
directions in the cleaning station
operating and maintenance manual.
1. Record the amount and TDS of
the permeate with the system set
at normal operating pressure.
2. Prepare about 15 gallons of the
inorganic cleaning solution
(approx. a pH of 2 - 3) in a
polypropylene or fiberglass
reinforced plastic tank with a
removable cover. Use RO water if
possible.
3. Connect a hose from the
cleaning solution tank to the inlet
of the pre-filter (pointer 2 on FIG.
3 and 4) from the cleaning
solution tank. Ensure a flooded
inlet to the pump or positive feed
pressure.
4. Feed the permeate and the drain
tubes back to the cleaning
solution tank so that the solution
will re-circulate during cleaning.
5. Turn on the reverse osmosis
pump. Adjust the concentrate
control valve (drain restrictor)
(pointer 5 on FIG. 3 and 4) to a
concentrate pressure of 50 psi.
Run the pump for about 30
minutes or longer.
6. Turn the machine off and
reconnect to the feed water
supply.
7. Turn the machine on and flush at
50 psi for 15 minutes or longer.
Discard all of the permeate and
concentrate water.
8. Adjust the system to normal
operating pressure and record the
amount and TDS of the permeate
water after the acid cleaning to
assess any improvements in the
system's performance.
9. Repeat this procedure for the
organic cleaning solution (with a
pH from 11 to 12).
10. Readjust the concentrate
pressure to original operating
pressure for normal operation.
After the cleaning procedure is
complete, check the amount and
TDS of the permeate to evaluate
the effectiveness of the cleaning
process.
EPRO 150-8000 O&M MANUAL Rev.04/03 Page 28 of 55
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