Science of Water : Concepts and Applications

344 The Science of Water: Concepts and Applications
Solution:
(Liquid polymer, lb)(liquid polymer % strength100) (polymer
solid, lb)(polymer solid % strength100) (x lb)(12100) (120
lb)(0.5100) (120)(0.005)
x
0.12
x 5lb
DETERMINING PERCENT STRENGTH OF MIXED SOLUTIONS
The percent strength of solution mixture is determined using the following equation:
Example 10.36
(solution 1, lb)(% strength of solution 1100) % Strength of mix
lb solution 1
(solution 2, lb)(% strength of solution
2100)
100
lb solution 2
Problem:
If 12 lb of a 10% strength solution are mixed with 40 lb of a 1% strength solution, what is the percent
strength of the solution mixture?
Solution:
(solution 1, lb)(% strength of solution 1100) % Strength of mix
lb solution 1
(solution 2, lb)(% strength of solution
2100)
100
lb solution 2
(12 lb)(0.1) (40
lb)(0.01)
100
12 lb
40 lb
12 lb 0.40
100
52 lb
31 .%
DRY CHEMICAL FEEDER CALIBRATION
(10.32)
Occasionally, we need to perform a calibration calculation to compare the actual chemical feed
rate with the feed rate indicated by the instrumentation. To calculate the actual feed rate for a dry
chemical feeder, place a container under the feeder, weigh the container when empty, then weigh
the container again after a specifi ed length of time (e.g., 30 min).