Introduction - Mathematics and Statistics for the Environment - page 17

■ EXAMPLE 1.5
Convert gallons to cubic feet.

Gallons
7.48 gal/ft

3

Cubicfeet (ft ) =

3

Problem: How many cubic feet of biosolids are removed when 18,200 gal are withdrawn?

Solution:

18,200 gal
7.48 gal/ft

3

Cubicfeet = = 2433 ft

3

■ EXAMPLE 1.6
Convert gallons to pounds.

Pounds (lb) = Gallons × 8.34 lb/gal

Problem: If 1650 gal of solids are removed from the primary settling tank, how many pounds of
solids are removed?

Solution:

Pounds = 1650 gal × 8.34 lb/gal = 13,761 lb

■ EXAMPLE 1.7
Convert pounds to gallons.

Pounds (lb)
8.34 lb/gal

Gallons (gal) =

Problem: How many gallons of water are required to fill a tank that holds 7540 lb of water?

Solution:

7540 lb
8.34 lb/gal

Gallons = = 904 gal

■ EXAMPLE 1.8
Convert milligrams/liter to pounds.

Key Point: For plant operations, concentrations in milligrams per liter or parts per million deter-
mined by laboratory testing must be converted to quantities of pounds, kilograms, pound per day,
or kilograms per day.

Pounds (lb) = Concentration (mg/L) × Volume (MG) × 8.34 lb/mg/L/MG

Problem: The solids concentration in the aeration tank is 2580 mg/L. The aeration tank volume is
0.95 MG. How many pounds of solids are in the tank?

Solution:

Pounds = 2580 mg/L × 0.95 MG × 8.34 lb/mg/L/MG = 20,441.3 lb