Basic Units of Measurement and Conversions - Basic Mathematics for Water and Wastewater Operators - page 65

■ Example 2.116
Convert milligrams per liter to pounds per day.

Pounds/day (lb/day) = Concentration (mg/L) × Flow (MGD) × 8.34 lb/MG/mg/L

Problem: How many pounds of solids are discharged per day when the plant effluent
flow rate is 4.85 MGD and the effluent solids concentration is 25 mg/L?

Solution:

Pounds/day = 25 mg/L × 4.85 MGD × 8.34 lb/MG/mg/L = 1011.23 lb/day

■ Example 2.117
Convert milligrams per liter to kilograms per day.

Kilograms/day = Concentration (mg/L) × Volume (MG) × 3.785 L/gal

Problem: The effluent contains 25 mg/L of BOD 5 . How many kilograms per day of
BOD 5 are discharged when the effluent flow rate is 9.3 MGD?
Solution:

Kilograms/day = 25 mg/L × 9.3 MGD × 3.785 L/gal = 880.01 kg/day

■ Example 2.118
Convert pounds to milligrams per liter.

Quantity (lb)
Volume (M

Concentration(mg/L) =

G) × 8.34 lb/MG/mg/L

Problem: An aeration tank contains 89,900 lb of solids. The volume of the aeration
tank is 4.40 MG. What is the concentration of solids in the aeration tank in milli-
grams per liter?

Solution:

89,000 lb

Concentration = = 2449.6 mg/L

4.40 MG × 8.34 lb/MG/m g/L

■ Example 2.119
Convert pounds per day to milligrams per liter.

Quantity (lb)

Concentration(mg/L) =

Volume (M GD) × 8.34 lb/MG/mg/L