Techniques for evaluation of mixing efficiency in an anaerobic digester

摘要

Mixing is a very crucial factor which has a significant effect on the efficiency of anaerobic digester. Mixing in digester is affected by various internal and external factors such as hydrodynamics of digester and impellers, viscosity of slurry, temperature and total solid content. In this study, various methods and techniques have been described that can be used to evaluate the effectiveness of any design employed for mixing in an anaerobic digester. The efficacy of different methods has been analyzed. Various numerical and empirical models have been developed in the past. Being a chemical process, mixing efficiency in anaerobic digester cannot be only described by numerical methods because the actual effect of shear stresses on the organisms can be determined by experimental methods. With a better knowledge of the relationship between mixing and biogas production rates, the overall process efficiency can be improved and optimized.