I need a step by step please and thank you. $9-4$ The company you work for plans to relcasc a waste stream containing $10mg*L^{-1}$ of phenol. Assuming that phenol degrades according the reaction:

$C_6{H}_{7}O+7\mathrm{.}25O_2$longrightarrow$6C{O}_2+3\mathrm{.}5H_{2}O$

calculate the theoretical carbonaceous oxygen demand of this waste stream.

$9-5$ If the $BO{D}_5$ of a waste is $220\mathrm{.}0mg*L^{-1}$ and the ultimate BOD is $320\mathrm{.}0mg*L^{-1},$ what is the rate constant?

Answer: $k=0\mathrm{.}233da{y}^{-1}$

$9-9$ Assuming that the data in Problem $9-5$ were taken at $20C,$ compute the rate constant at a temperature of $15C.$

Answer: $k=0\mathrm{.}124$ day ${?}^{-1}$

$9-19$ The Waramurungundi tannery with a wastewater flow of $0\mathrm{.}011m^3*s^{-1}$ and a $BO{D}_5$ of $590mg*L^{-1}$ discharges into the Djanggawul Creek. The creek has a $10-$year, $7-$day low flow of $1\mathrm{.}7m^3*s^{-1}.$ Upstream of the Waramurungundi tannery$,$ the $BO{D}_5$ of the creek is $0\mathrm{.}6mg*L^{-1}.$ The BOD rate constants $(k)$ are $0\mathrm{.}115da{y}^{-1}$ for the Waramurungundi tannery and $3\mathrm{.}7da{y}^{-1}$ for the creek. Calculate the initial ultimate BOD after mixing.

Answer: $9\mathrm{.}27mg*L^{-1}$

$9-21$ Using the data given below:

Calculate the DO concentration just after mixing $($in unit of $mg*L^{-1}).$

$\backslash$table$[[,$Oz WWTP Effluent,Babbling Run$],[$Flow$,m^3*s^{-1},0\mathrm{.}36,4\mathrm{.}8],[$ult$-$BOD at $20C,mg*L^{-1},27,1\mathrm{.}35],[DO,mg*L^{-1},0\mathrm{.}9,8\mathrm{.}5]]$

$($Note: WWTP $=$ Wastewater Treatment Plant, Babbling Run: upstream from outfall$)$ Answer: $7\mathrm{.}970mg*L^{-1}$