Physicochemical and microbiological dynamics in composting of organic waste using a new bioreactor model

Abstract

Background It is important to use renewable resources to minimize the environmental risks and the composting is one of the most sustainable methods for the management of organic waste. Methods The objective of this work was to evaluate the physicochemical dynamics of microorganisms and to study cultivable microorganisms during the composting process of organic residues in a new model of bioreactor. The formulation of a possible cocktail of microorganisms selected for use as a compound accelerator will be further investigated. In addition, the use of two inoculants (non-commercial inoculum (NCI)) and commercial inoculum (CI)) and a control without inoculant during the composting process will be analyzed to evaluate its efficiency. Composting was performed by mixing organic waste from the garden waste and University Restaurant, obtaining an ideal C/N ratio of 30:1. The composting process was carried out in 1 m3 composters with controlled temperature and aeration. Results The thermophilic phase for all treatments was reached by the second day. Mature compost was obtained after an average of 120 days and composting in all treatments showed an increase in the availability of P and micronutrients. During composting, the population of bacteria and actinobacteria were higher than those of yeasts and filamentous fungi. Conclusions Increased composting efficiency was observed when starter cultures were used, the treatments presented advantages such as greater mineralization of P-available and micronutrients as Mn and Zn, in terms of the quality of the final product in comparison to the control treatment.