b$.$ Determine the SRT of an activated sludge system with raw sewage flow of $4000($m$^(3))/($d$),$ aeration

tank volume of $1,000$m$^(3),$ MLSS concentration of $3,000$m$($g$)/($L$),$ waste sludge production of $80$

$($m$^(3))/($d$),$ and the return activated sludge solids concentration of $8,000$m$($g$)/($L$).$ If the secondary

clarifier area is $250$m$^(2),$ find out the solids loading rate and surface overflow rate. $(15$ marks$)$