24
(3)
As soon as the NaClO is detected in the drainage water, close the drainage
valve (V-3).
(4)
After making sure water comes out from upper part of the side nozzle of the
membrane module, stop the NaClO feed pump, close the backwashing valve
(V-6) and stop the backwashing pump.
(5)
Soak the membrane in the chemical for a fixed time (normally 20 minutes).
And then, open the air-scrubbing valve (V-2) for a fixed time (normally 60
seconds).
The air flow rate for air-scrubbing should be within
the range below. Excessive air flow rate may
damage the hollow fiber membrane.
HFU-B2315AN: 3.6 – 6.7 Nm
3
/h, normally 4.5 Nm
3
/h
(2.1 – 3.9 scfm, normally 2.6 scfm)
The maximum required air pressure during the air-
scrubbing for inside of the module will be 40 kPa
(6 PSI).
(6)
Close the air-scrubbing valve (V-2), open the drainage valve (V-3) to drain
the chemical from the membrane module.
(7)
Close the drainage valve (V-3), and then open the backwashing valve (V-6)
and run the backwashing pump (normally 30 seconds). Stop the
backwashing pump and close the backwashing valve (V-6), and then open
the air-scrubbing valve (V-2) (normally 30 seconds). Repeat this procedure
until the overflow water meets the required water quality.
(8)
Repeat the process of (7) until the overflow water meets the required water
