Parâmetros físico, químicos e de toxicidade no processo de compostagem de resíduos orgânicos de serviços alimentares

Abstract

Facing the growing generation of organic residues in the foodservice sector, composting emerges as an alternative for treating the organic fraction of this material directly at the source. In this context, the objective of this work was to evaluate the stabilization of organic residues from the pre-preparation and post-preparation of food services in an experiment of two different volumes by the composting process, through the physical, chemical, and toxicological parameters. To carry out this work, an experiment was developed in a 2x3 factorial, with two different volumes (90 and 180L) and three different materials, namely: pre-preparation residues, post-preparation, and pre and post-preparation in equal proportion. In all reactors, rice husk was used as a structuring material. The experiments were carried out in duplicate and were kept sheltered from the weather from December 2018 to April 2019, comprising 120 days, with revolving and removal of analytical samples every 30 days. During this period, the response variables used were compost temperature and humidity and the environment, as well as the presence of vectors. In the samples taken, physical-chemical parameters were analyzed, such as pH, Electrical Conductivity, Organic Carbon, Total Kjeldhal Nitrogen, Carbon and Nitrogen Ratio, Moisture Content, Mineral Matter and Total Phosphorus and Phytotoxicological Analysis. It was possible to verify in all the experimental conditions a standard curve of microbial development in composting, which includes the thermophilic phase. The results showed that the physical-chemical parameters were partially adapted to the limit stipulated by the current Brazilian legislation, except for the C/N ratio of the treatments with pre-prepared residues, which resulted in values higher than recommended. Regarding phytotoxic results, all treatments reached values within the limit recommended by international organizations od toxicological control, thus indicating the absence of toxicity in the organic compost. Therefore, it is possible to conclude that treatments with pre-preparation residues should only be used in conjunction with post-preparation residues and that these can be used only with the addition of structuring material.