What is the reportable BOD for a 30 ml wastewater sample incubated for 5 days at 20 degrees C with an initial DO of 6.0 mg/L and final DO of 3.5 mg/L?

To determine the reportable Biochemical Oxygen Demand (BOD) from the given data, we need to follow the BOD calculation formula, which is based on the change in Dissolved Oxygen (DO) in the sample.

First, calculate the change in DO:

Initial DO: 6.0 mg/L

Final DO: 3.5 mg/L

Change in DO = Initial DO - Final DO = 6.0 mg/L - 3.5 mg/L = 2.5 mg/L

Next, since this change in DO corresponds to a 30 mL sample, we need to adjust this value to report it on a per-liter basis. To do this, we multiply the change in DO by a factor to convert it to a 1-liter sample.

Since there are 1000 mL in a liter, the calculation for BOD is:

BOD (in mg/L) = Change in DO (in mg/L) * (1000 mL / Sample Volume in mL)

BOD (in mg/L) = 2.5 mg/L * (1000 mL / 30 mL)

BOD (in mg/L) = 2.5 mg/L *