2-9. OPERATING PROCEDURES - cont.
Examine Clarity of Filtered Water. Refer to figure 2-59.
Get plastic 1000 ml graduated cylinder (called turbidity tube) used for checking clarity of water. The
turbidity tube is identified by a white bullseye set in a black background disc.
Go to the drain valves on the left side of the ROWPU (below R.O. tubes).
Slowly open DRAIN NO. 1 CARTRIDGE FILTER valve and allow water to flow for 20 to 30 seconds.
Draw a sample of 600 milliliters of water into the turbidity tube. Close valve.
Look down into turbidity tube and you should be able to see clearly both the white bullseye and black
disc at the bottom of the tube.
If both white bullseye and black disc cannot be seen clearly, run the ROWPU another 10 minutes, then
repeat steps (3 and 4).
If after second sampling white bullseye and black disc still cannot be seen clearly, proceed as follows:
Increase chemical feed pump POLYMER control knob (figure 2-56) setting by two index marks
(turn knob to the left).
The previous settings of 20 or 60 ml/min polymer flow was an initial setting to prevent overdosing of
polymer. This rate may be adjusted during operation to improve water clarity.
Run ROWPU for 5 minutes, then take another water sample as described in steps (3) and (4).
Unless source water is noticeably turbid, it should not be necessary to increase POLYMER setting beyond 5.
Repeat steps (a) and (b) until bullseye and black disc in turbidity tube can been seen clearly.