Influence of environmental parameters on the composting kinetic of lignocellulosic residues
The kinetic of the thermophilic composting process of trimming residues was studied under several parameters [moisture (40-70%), aeration (0.2-0.6 l air/kg min) and particle size (1-5 cm)] in order to determine the best composting conditions to ensure an optimum composting design. Under those conditions, suitable temperature evolutions have been found for all the reactors. The kinetic model proposed by Whang and Meenaghan was used and two first-order kinetic equations were used for describing the composting process. A central composite experimental design was used and a second-order polynomial model consisting of the three selected independent process variables was found to accurately describe (the differences between the experimental values and those estimated by using the equations never exceeded 10% of the former) the kinetic process. The magnitude of the constants among the studied conditions varies among 5 and 13.9 for 1/K1 and 0.0015 and 0.0035 for K2. Both, moisture and particle size affects positively and negatively the composting process and low effect of aeration (among studied values) was found. The values of 1/K1 and K2 obtained showed higher values for both parameters under 55% moisture content, 5cm particle size and 0.2 lair/min kg.