A wastewater from a fermentation facility contains 800mg/L acetic acid and 1200mg/L ethanol. A suspended-growth, complete-mix, continuous-flow anaerobic digester is used to convert the wastewater into...

A wastewater from a fermentation facility contains 800mg/L acetic acid and 1200mg/L ethanol. A suspended-growth, complete-mix, continuous-flow anaerobic digester is used to convert the wastewater into biogas. The target conversion efficiency for both acetic acid and ethanol is 95%. In the anaerobic digestion process methanogenesis is the limiting step for the conversion. The kinetics of the digestion follows Monod model and the kinetic constants for the methanogenic microbes at 35°C are Maximum specific substrate utilization rate k=4 day−1 Half velocity constant KS =40mg COD/L Yield Y=0.06g biomss/g COD a. Assume that the microbial decay can be neglected, what is the appropriate HRT for the anaerobic digester to achieve the conversion at 35°C? b. If the temperature is increased to 50°C, what is the appropriate HRT for the anaerobic digester to achieve the same conversion efficiency?