Process Description and Rate Equations

The feed material essentially consists of organisms with the concentration Cxs measured in mol/m3 and of substrate with the concentration Csf in mol/m3. This is fed to the anaerobic digester at a daily volumetric feed flow rate of q to3/day. The development of the model design equations involves the following assumptions  

The reactions of interest take place only in the liquid phase and the reactor s volume V in m3 is constant. 

The organism concentration Cx in the digester is uniform, as is the substrate concentration Cs. (The digester is perfectly mixed like a CSTR.) 

We can obtain a model, i.e., the design equations for the digester process, by carrying out organism and substrate balances and using the following relationships  

Here po is the maximum specific growth rate and Ks is the saturation constant. 

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