The BOD of a wastewater discharge is to be determined. 10 mL of the wastewater is placed in a 300 mL bottle, and the bottle is filled with dilution water containing seed bacteria and nutrients. A 300 mL bottle containing only dilution water is run in parallel with the sample bottle. Both bottles are incubated for 5 days at 20°C. The dissolved oxygen readings are as follows: Initial dissolved oxygen concentration in water sample, DOi = 2.0 mg/L. Final dissolved oxygen concentration in dilution water, DOg = 8.0 mg/L. Final dissolved oxygen concentration in dilution water, DOf = 3.4