Introduction - Mathematics and Statistics for the Environment - page 20

■ EXAMPLE 1.17
Convert gallons per minute (gpm) to million gallons per day (MGD).

Flow (gpm) 1440 min/day
1,000,000

×

Flow (MGD) =

gal/MG

Problem: The flow meter indicates that the current flow rate is 1469 gpm. What is the flow rate in
million gallons per day?

Solution:

1469 gpm 1440 min/day
1,000,000 gal/MG

×

Flow = = 2.12 MGD (rounded)

■ EXAMPLE 1.18
Convert gallons per day (gpd) to million gallons per day (MGD).

Flow (gal/day)
1,000,000 gal/MG

Flow (MGD) =

Problem: The totalizing flow meter indicates that 33,444,950 gal of wastewater have entered the
plant in the past 24 hr. What is the flow rate in million gallons per day?

Solution:

33,444,950 gal/day
1,000,000 gal/MG

Flow = = 44 MGD 33.

■ EXAMPLE 1.19
Convert flow in cubic feet per second (cfs) to million gallons per day (MGD).

Flow (cfs)
1.55 cfs/MG

Flow (MGD) =

Problem: The flow in a channel is determined to be 3.89 cubic feet per second (cfs). What is the flow
rate in million gallons per day (MGD)?

Solution:

3.89 cfs
1.55 cfs/MG

Flow = = 2.5 MGD

■ EXAMPLE 1.20
Problem: The water in a tank weighs 675 lb. How many gallons does it hold?

Solution: Water weighs 8.34 lb/gal; therefore,

675 lb
8.34 lb/gal

= 80.9 gal