A perspective on the use of respiration indices beyond the measurement of the stability of compost

Abstract

Respiration indices (RI) have been massively used for the determination of stability of compost and, more broadly, organic amendments applied to soils. However, being a measure of the overall respiration of an organic matrix, they have also been used for other relevant issues of waste management, most of them based on the equivalence between the respiration index and the actual biological activity. In the composting field, RI have shown to be very useful to monitor the performance of the process when studied at full-scale in simple or complex biologically-based waste treatment plants. They also can be used for advanced control strategies of the process. More generally, RI coupled with biochemical methane tests, are an accurate measure of a critical parameter as the C/N ratio, based on biodegradable carbon instead of total organic carbon. In LCA, RI can be used to provide consistent novel functional units to obtain reliable environmental impacts for waste management scenarios. Finally, the role of RI related to the new paradigm of changing “waste” to “raw materials” in the framework of circular bioeconomy through solid-state fermentation is put into perspective. In summary, the objective of this perspective paper on RI is to discover their new uses beyond the measurement of the stability of compost, in crucial topics related to circular bioeconomy applied to waste management.