A $1220-$mm$-$diameter concrete sewer $($Manning$$s coefficient, n$=0\mathrm{.}013)$ is to carry $0\mathrm{.}50$ m$^3/$s of domestic wastewater at a temperature of $23$ deg C on a slope of $0\mathrm{.}009.$ Estimate the maximum $5-$day BOD $($BOD$5)$ for which

hydrogen sulfide generation will not be a problem. $($Expected answer range: $750\mathrm{.}0$ mg$/$L $<=$ BOD$5<=900\mathrm{.}0$ mg$/$L$)$