Assessment and comparison of the leaching behavior of two types of compost materials from aerobic/anaerobic biodegradation processes

This study aimed at assessing and comparing the leaching behavior of two types of compost produced from an aerobic composting process and from a combination of anaerobic and aerobic biodegradation processes, respectively. For this purpose, static batch and dynamic column leaching tests were performed. The obtained results revealed a similar leaching behavior for the two materials although the input biowaste and the treatment conditions are quite different. Furthermore, for both composts, a strong similarity between the leaching pattern of the dissolved organic carbon (DOC) and the one observed for most metals was observed. Hence, specific correlation coefficients between the DOC and metals concentrations were derived. The latter were then integrated in a screening model proposed and developed in a previous study which allows to describe the DOC release as a function of the L/S ratios. The comparison with the experimental leaching data highlighted that the screening model replicates quite well the release trend observed for most metals, suggesting that from the DOC value of an organic-rich material a reliable estimation of the release of metals can be attained by employing a simplistic approach.