Efeito da adição de casca de aveia em biopolímeros compostados com resíduos orgânicos e poda de árvores

Abstract

Biopolymers become increasingly important to the package production that makes easy the waste management, especially the organics in composting plants. The present study intends to evaluate the compostability of biopolymers made from starch with and without oat straw addition, in composting process with domestic organic waste and tree pruning. The composting lasted 60 days and was made in 100 L reactors, being that 30 L was domestic organic waste and 66 L was pruning tree. The experiment was made in duplicate, being the treatments the types of biopolymers (with and without oat straw addition) and the witness (without biopolymers). Were monitored the following parameters along the composting: temperature, C/N ratio, total organic carbon, total nitrogen, pH, electrical conductivity, solids, humidity content, micro and macronutrients and weight and volume reduction. At the end of the process, biopolymers degradation was analyzed with the assistance of photographic records and scanning electron microscopy. The biopolymers didn’t act upon temperature parameter and the thermophilic phase was observed for about 11 days; the pH was stabilized near to 9 e the electrical conductivity was higher at the end of the process. There was a reduction of volatile solids, C/N ratio, volume and mass of the compounds. The photographic records showed that the biopolymer without oat straw degraded more than the biopolymer with oat straw and the scanning electron microscopy images showed cracks, holes and irregular surfaces that didn’t exist on the biopolymer before the composting. It is concluded that the presence of the biopolymers didn’t interfere in the composting or in the final compound quality. And the composting time wasn’t enough to completely degrade the biopolymers.