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# Calculations of Biochemical Oxygen Demand

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Info:
BOD: Biochemical Oxygen Demand
BOD5 is the total amount of oxygen consumed by microorganisms during the first five days of biodegradation

BOD5 = (DOi - Dof)/(P) this is the five-day BOD of a diluted sample
Where DOi = the initial dissolved oxygen (DO) of the diluted wastewater
DOf = the final DO of the diluted wastewater, 5 days later
P = the dilution fraction = (volume of wastewater)/(volume of wastewater plus dilution water)
A standard BOD bottle holds 300 mL, so P is just the volume of wastewater divided by 300 mL

5.31)
For the following waste and river characteristics just upstream from the outfall, find the minimum downstream DO that could be expected:

Parameter Wastewater River
Flow (m^3/s) 0.3 0.9
Ultimate BOD (mg/L) 6.4 7.0
DO (mg/L) 1.0 6.0
Kd (day^-1) -- 0.2
Kr (day^-1) -- 0.37
Speed (m/s) -- 0.65
DOsat (mg/L) 8.0 8.0