Chemistry · Environmental Chemistry

A wastewater sample uses 20 mL diluted to 300 mL. The measured dissolved oxygen (DO) values are: initial DO of diluted sample D1 = 9.0 mg/L, final DO of diluted sample after 5 days D2 = 3.0 mg/L, initial DO of seed control B1 = 9.2 mg/L, and final DO of seed control after 5 days B2 = 8.5 mg/L. Assuming the seed ratio in the diluted sample is 1:1 relative to the control, calculate the 5-day Biochemical Oxygen Demand (BOD5).