Kinetics of anaerobic treatment: A critical review

The fundamentals of microbial kinetics and continuous culture models are presented. The kinetics of the anaerobic treatment processes are reviewed recognizing that anaerobic degradation of complex, polymeric organic materials is a combination of series and parallel reactions. Such reactions include hydrolysis, fermentation, anaerobic oxidation of fatty acids, and methanogenesis. The intrinsic rates of each step are reviewed and literature data summarized. Whenever possible, available kinetic information is summarized on the basis of substrate composition (such as carbohydrates, proteins, and lipids). The effect of temperature and inhibitors on the intrinsic kinetic rates is discussed. Stoichiometric and bioenergetic considerations are reviewed. Mass transfer limitations (both external and internal)associated with biofilms and microbial agglomerates, in general, and their effect on the intrinsic kinetic rates are presented. Areas requiring further research are identified.