EFFECT OF DIFFERENT AERATION FLOWRATES AND MODES ON THE DYNAMIC RESPIRATION ACTIVITY OF SOLID ORGANIC RESIDUES

摘要

Goal of the experimental work was to assess the effect of different air flowrates and different aeration modes on dynamic respiration indices during composting of organic substrates. The aeration modes selected were two: a constant flowrate throughout the experiment and a continuously adjusted airflowrate that always optimizes the oxygen uptake rate (OUR) based on the reading of the previous OURs. Experiments took place in 500 mL custom made respirometers. Three substrates were used namely: a fresh MSW derived organic fraction (OFMSW), a semistabilised MSW derived organic matter fraction (SSOM) and a stabilized compost also derived from the OFMSW. Results showed that beyond an air flow of approximately 20 L air kg-1 DM h~(-1), at the constant flow mode, the resulting DRI and AT4 were statistically similar. At the OUR based aeration mode, the DRI and AT4 were statistically similar at all initial flowrates for all three substrates. It was also observed that above a minimum threshold value (around 3000 L kg-1 DM), the respiration activity remained constant, which is important knowledge during the operation of composting facilities.