NIRE-170-1-6
16
PIA
a mm
P1
P2
PIA
b mm
(3) Required ancillary devices for membrane filtration process are listed below. In some
instances additional components may be required.
a. Fine screen
Incoming wastewater to the membrane tank should pass through a screen having
3.0 mm or less openings. Failure to incorporate a screening device will result in
clogging or permeant damage to the membrane. Mesh type screens are
recommended. Overflow or waste carryover into the submerge membrane tank must
be avoided at all times.
b. Flow control device
A flow rate controller, a flow meter combined with an automatic control valve, or a
flow meter combined with VFD controlled suction pump should be installed on the
filtrate water line to control the flow rate of filtrate water. When operating more than
one
“NHP210 Series” module simultaneously it is recommended that each train be
fitted with its own discreet filtrate flow rate controller.
c. Trans-membrane pressure (TMP) measurement & calculation
For trans-membrane pressure (TMP) determination the differential pressure (in the
filtrate line and water level) needs to be measured and calculated. This can be
accomplished by either installing two pressure sensors and calculating the
difference in the readings in the PLC or using a differential pressure gauge.
When using two pressure gauges, one pressure gauge should be installed on the
filtrate water line and the other on the membrane tank, to monitor the
trans-membrane pressure. When operating a number
of “NHP210 Series” modules
simultaneously in one train, it is advised to install one differential pressure
measuring instrument for each train.
[Example]
Fig.IV-4 Trans-Membrane Pressure Measurement & Calculation
