ABSTRACT
A filter backwash rate is a measurc of the gprn flowing upward through each sq ft of filter surface area The calculation of backwash rate is similar to filtration rate.
Backwash = mow, gpm Rate Area, sq ft
Example 1: (Backwash Rate) D A filter with a surface area of 150 sq ft has a backwash flow rate of 2900 gpm. What is the filter backwash rate in
(10 ft) (15 ft)
2900 gpm 150 sq ft
(25 ft) (10 ft)
Backwash = Flow, gpm Rate Area, sq ft
(25 ft) (10 ft)
Example 3: (Backwash Rate) O A filter 15 ft by 15 ft has a backwash flow rate of 3150 gpm. What is the filter backwash rate in gpm/sq ft?