What is the required backwash flow rate for a mixed media filter that is 10 feet wide and 12 feet long, with a backwash rate of 10 gpm per square foot?

To determine the required backwash flow rate for the mixed media filter, you need to calculate the area of the filter and then multiply it by the backwash rate per square foot.

First, the area of the filter is found by multiplying its width by its length. In this case, the filter is 10 feet wide and 12 feet long, which gives us:

Area = Width × Length = 10 feet × 12 feet = 120 square feet.

Next, since the backwash rate is given as 10 gallons per minute (gpm) per square foot, you can calculate the total backwash flow rate by multiplying the area by the backwash rate:

Total Backwash Flow Rate = Area × Backwash Rate

= 120 square feet × 10 gpm/square foot

= 1,200 gpm.

This result aligns with the calculated total flow rate, confirming that the required backwash flow rate for the mixed media filter is indeed 1,200 gpm. This figure is essential for ensuring the effective cleaning of the filter media during the backwash process, maintaining the filter's efficiency and performance.