The microbiological basis of process control in methanogenic fermentation of soluble wastes

The essential requirement for anaerobic digestion of industrial wastes is that the process should operate reliably at high performance. In the digestion of dilute, soluble wastes it is necessary to retain the active biomass within the digester at short liquid retention times for the process to be economically feasible and this is reflected in digester design. Performance of digesters can only be assessed by interpretation of measurable parameters such as pH₂, E_h, pH, volatile fatty acid concentrations, temperature, gas production, biomass content and feed rate and composition. The effects of changes in these parameters on the microbiology of methanogenic digestion and the application of this knowledge in control of the process is discussed.