$7-45.$ Assuming that the mixed oxygen deficit $D_a$ is zero and that the ultimate

BOD $L_r$ of the Looking Glass River above the wastewater outfall from

Carrollville is zero, calculate the amount of ultimate BOD, in $k\frac{g}{d},$ that

can be discharged if the DO must be kept at $4\mathrm{.}00m\frac{g}{L}$ at a point $8\mathrm{.}05km$

downstream. The stream deoxygenation rate $k_d$ is $4\mathrm{.}14d^{-1}$ at $12C,$ and the

reaeration rate $k_r$ is $5\mathrm{.}07d^{-1}$ at $12C.$ The river temperature is $12C.$ The

river flow is $5\mathrm{.}95\frac{m^3}{s}$ with a speed of $0\mathrm{.}300\frac{m}{s}.$ The Carrollville waste$-$

water flow is $0\mathrm{.}0130\frac{m^3}{s}.$

Answer: $Q_w{L}_w=1\mathrm{.}14{10}^{4}k\frac{g}{d}$ of ultimate BOD