A BOD test is run using $100mL$ of treated wastewater mixed with $200mL$ of pure water. The

initial DO of the mix is $8\mathrm{.}5m\frac{g}{L}.$ After $5$ days, the DO is $3\mathrm{.}8m\frac{g}{L}.$ After a long period of

time, the DO is $2\mathrm{.}0m\frac{g}{L}$ and it no longer seems to be dropping. Assuming nitrification has

been inhibited so only carbonaceous BOD is being measured,

a$)$ What is the $BO{D}_5$ of the wastewater?

b$)$ Assuming no nitrification effects, estimate the ultimate carbonaceous BOD.

c$)$ What would be the remaining BOD after five days have elapsed?

d$)$ Estimate the reaction rate constant $).$

e$)$ Explain in words the relationship between "ultimate BOD" and "remaining BOD."