Kinetic analysis of forced aeration composting - I. Reaction rates and temperature

The kinetics of the forced aeration composting process operated under diffe rent aeration modes was studied using two specifically designed heat insula ted closed pilot-scale reactors. Five pilot scale composting tests using fr esh mixture of organic solid waste were performed. The modes of aeration ap plied were upflow, downflow, alternate upflow/downflow, and internal air re circulation. Temperatures at different heights of the composting mass and a ir velocity were continuously monitored. Air flow was continuous or intermi ttent depending on temperature. Kinetic analysis showed that (i) temperatur e dependence of the reaction rates of all different aeration mode compostin g tests clearly followed the Arrhenius equation; (ii) the degradation of or ganic solids could be quantitatively predicted using the first order reacti on model; and (iii) extent of degradation in the composting mass could be p redicted on the basis of outlet air temperature instead of internal tempera ture of the composting mass.