A biofuel manufacturing industry generates $50$ m$3/$h of wastewater with a COD$=6000$ mg O$2/$L biodegradable organic matter concentration. Municipal legislation requires that wastewater from any industrial activity discharging into the municipal sewer must have a COD$<1000$ mg O$2/$L$.$ To comply with the regulations and due to the high organic load of the wastewater, an anaerobic treatment with a complete mixing reactor is proposed, which requires subsequent sedimentation of the microorganisms leaving the reactor. A part of the thickened stream in the settler is recirculated to the reactor in order to maintain a constant concentration of microorganisms in the mixed liquor $($SSVLM$=10$ kg SSV$/$m$3).$ Another part of the thickened stream is purged to remove excess microorganisms that have been generated in the process.Knowing that the reactor produces $3300$ kg$/$d of biogas, that the concentration of microorganisms in the recirculation stream is $2\%$ w$/$w and that the secondary settler has a solids removal efficiency of $99\mathrm{.}5\%,$ we ask to calculate:

Data;

Biogas: $70\%$ by volume of methaneCell yield

$($Y$)$: $0\mathrm{.}04$ kg SSV$/$kg COD

Atomic masses: C:$12$; H: $1$; O: $16$

Density of all streams similar to water

Biogas flow rate generated: $3029\mathrm{.}6$ Nm$3/$d$,$

Percentage of COD removed $\%84\mathrm{.}1$

Px$=242\mathrm{.}4$ kg SSV$/$d$,$

Please calculate;

Recirculation flow rate $($QR$)($m$3/$d$)$

Purge flow rate $($QW$)$ and clarified effluent $($Qe$),$ expressed in m$3/$d

Concentration of SSV $($Xe$)$ in the clarified effluent $($mg$/$L$)$

The COD concentration $($mg$/$L$)$ of the microorganisms $($SSV$)$ in the clarified effluent, considering that the microorganisms have the chemical formula C$5$H$7$NO$2.$ Does the clarified effluent comply with the discharge limits$?$

If the generated biogas stream is burned for energy, what would be the CO$2$ emission $($kg$/$d$)$ from the combustion process?