Q$3(7\mathrm{.}5$ pts$).$ A city has a wastewater treatment plant $($WWTP$)$ that discharges the city's treated

wastewater into the river. Both the waste stream and the river are at $20C.$ The city council has asked that

you determine whether the discharge from the WWTP will reduce the DO below the state standard of

$5\mathrm{.}00m\frac{g}{L}$ at Big Fish Junction, $6\mathrm{.}78km$ downstream of the discharge point. The pertinent data are as

follows:

HINT: $(1)$ Calculate the initial BOD after mixing $($See hint $3$ above$)$

$(2)$ Calculate the initial oxygen deficit $($using $\{$:$Da=D{O}_s-\frac{Q_w**D{O}_w+Q_x**D{O}_x}{Q_k+Q_s})$

$(3)$ Calculate travel time to Big Fish Junction $-$ this is just doing some unit conversions with water

velocity $(0{)}_{{?}_{?}}$

$(4)$ Calculate oxygen deficit at Big Fish Junction $-$ use $D=k_d**\frac{L_a}{k_d-k_d}**(expdots-$expdots$)+D_a(expdots)$

equation from notes!

$(5)$ Calculate $DO$ at Big Fish Junction $(DO=D{O}_s-D=$dots$)$ Note $D{O}_s$ is in table and $D$ is answer from $(4)$