A MODEL FOR EVALUATION OF ANAEROBIC DEGRADATION CHARACTERISTICS OF ORGANIC WASTE - FOCUSING ON KINETICS, RATE-LIMITING STEP

A kinetic study for an anaerobic batch reactor was performed to evalua te quantitatively the effect of substrate characteristics on the anaer obic degradation of organic waste. The kinetic behavior of anaerobic d egradation was described as a first order series reaction that is a co nsecutive reaction of acidogenic- and methanogenic-fermentation. DR (D eterminant of Rate limiting step) that is based on balancing between t he rates of the reaction steps was defined, that is the logarithmic di fference between maximum acidification rate and maximum methanation ra te. Anaerobic degradation characteristics, such as the kinetic and rat e limiting step, could be evaluated by the value of DR. DR depended on PR (Pivotal Ratio) that is a ratio of ultimate methane yield to maxim um methane production rate. PR could be obtained easily by using a fir st order kinetic analysis for overall anaerobic degradation, and it wa s considered as a useful parameter to estimate approximately the chara cteristics of anaerobic degradation for organic waste. This simple eva luation method for the degradation characteristics of organic waste mi ght be used for the optimization of performance, staler operation, as well as better control and design of anaerobic digestion system.