QUESTION $2.$

You are asked to characterize an unknown wastewater sample collected at the outfall of a food industrial site that your municipality suspects of illicit discharge. You first run a COD test on the sample and determine that the COD$=1500m\frac{g}{L}.$ You remember from your course notes that a typical ratio of COD:BOD is ${?}^{2}1\mathrm{.}8.$

Given that the laboratory is at $20C$ and assuming full saturation of the dilution water, what wastewater sample volume range $($provide a maximum volume value and a minimum volume value to get full marks$)$ would you recommend the lab use to determine the $BO{D}_5$ of the sample with accuracy?

Assume that the $BO{D}_5$ of the seed is zero. Also keep in mind that there must be a change in DO of at least $2m\frac{g}{L}$ and a minimum DO reading of $2m\frac{g}{L}$ in the BOD bottle during the $5-$day measurement to get accurate results. Note that BOD bottles have a volume of $300mL.$