Culligan M1 Series Installation, Operation And Service Instructions page 80

Rejection and Recovery
Feed water entering the system is split into two streams, a product stream and a concentrate stream. See Figure 58.
Figure 58.
During the process of reverse osmosis, some of the water has its dissolved solids content reduced by approximately 98
percent. This high quality product water is sent to service.
The rest of the feed water contains the dissolved solids removed from the product water, in addition to the dissolved solids
already present in the feed water. This concentrate water is sent to drain.
The amount of total dissolved solids rejected by the system is expressed as a percentage. A 90 percent rejection means
that 90 percent of the dissolved solids have been removed from the feed water by the system. To calculate the percent
rejection, use the following equation:
Where Feed TDS is the total dissolved solids content of the water going into the system, and Product TDS is the total
dissolved solids content of the high quality product water. The TDS needs to be measured with a handheld meter.
For example, if the Feed TDS is 600 ppm and the Product TDS is 24 ppm,
The amount of high quality water recovered for use as a percentage of the water fed into the reverse osmosis system is
called percent recovery. Use the following equation to calculate percent recovery:
NOTE Numbers used in these examples might not reflect those of your unit.
CAUTION! An understanding of rejection/recovery percentages and temperature compensation
is essential for monitoring and evaluating the performance or condition of the reverse
osmosis system. DO NOT operate the system before becoming familiar with these
concepts.
Temperature Compensation
As the feed water temperature decreases so will the product water production. The rated product flow (gallons per minute,
gpm) as shown for the various models on
76 Culligan® M1 Series Reverse Osmosis
Feed water product stream and concentrate stream.
(Feed TDS - Product TDS)
(Feed TDS)
600-24
x 100 = 96% Rejection
600
Product Water Flow Rate (PFLOW)
Feed Water Flow Rate (FFLOW)
page 3 is based upon the feed water temperature equal to 77° F.
x 100 = % Rejection
x 100 = % Recovery
76 Cat. No. 01022940