MATHEMATICAL MODELLING OF ANAEROBIC DIGESTION PROCESS

Abstract

The present study deals with mathematical modelling of anaerobic digestion process. The models of anaerobic digestion have earlier been developed by several investigators but these models do not adequately represent the process and could not be of much use in controlling and improving the process. In the present work use has been made of uptodate theoretical knowledge and available practical data to develop linear and non-linear models. On the basis of systems approach and standard numerical methods of solving the equations. The validity of the model have been checked by comparing observed and calculated values and error analysis. The interaction among various state parameters of anaerobic digestion like pH, alkalinity, volatile acids, volatile solids, nutrients and tem-perature have been incorporated on rational basis and modelled to depict and improve the control strategies in place of empirical rules. It has been concluded from this study that pH, volatile solids concentration and temperature are more important parameters than alkalinity, total nitrogen and volatile acids. • It also showsthat anaerobic digestion process can be represented more accurately by non-linear models rather than linear models.