Utilização de diferentes tipos de resíduos agroindustriais como substrato na compostagem de biossólido industrial.

Abstract

If, on the one hand, agribusiness is prominent in the national economy, on the other, it is also in the generation of waste, which, if untreated and accumulated in a disorderly way in the environment, due to its physicochemical and microbiological characteristics, cause pollution of water and soil, as well as the spread of disease and the emission of unpleasant odors. The implementation of sustainable agroindustrial practices aimed at the treatment and reuse of these wastes are essential for the reduction and / or minimization of associated environmental impacts, in compliance with the Federal Law No. 12,305 / 2010, which establishes the National Solid Waste Policy (PNRS). In this context, the objective of this study was to develop and analyze the physical, chemical, microbiological and toxicological characteristics of organic compounds produced with different types of agroindustrial residues (sawdust, poultry litter, smoke powder and rice hulls). industrial biosolids composting. Four replicate treatments were set up: ST1 - 12 m³ of sawdust and 7 m³ biosolid; ST2 - 6 m³ sawdust, 6 m³ bird bed and 7 m³ biosolid; ST3 - 6 m³ sawdust, 6 m³ smoke powder and 7 m³ biosolid and ST4 - 6 m³ sawdust, 6 m³ rice husk and 7 m³ biosolid. The values of pH, total organic carbon - TOC and temperature for all treatments analyzed did not present a statistically significant difference (p> 0.05) during the composting process. On the other hand, the nitrogen values presented a significant difference (p <0.05) for the ST1 treatment, which presented a significant reduction in its concentration, ie, 1.64% and ST2 treatment, which reached a high percentage of concentration at 126 days, ie, 4.09%. The phosphorus values of the ST1, ST3 and ST4 treatments did not differ statistically (p> 0.05) as opposed to the ST2 treatment, which presented a significant increase in its final concentration, ie, 3.65%. The values of ST2, ST3 and ST4 did not differ significantly (p> 0.05), but the ST1 treatment presented a significant difference (p <0.05) in relation to the ST4 treatment due to its initial value of relatively high humidity, that is, 62.84%. The electrical conductivity values of the ST1 and ST4 treatments did not differ statistically (p> 0.05) among themselves, as did the ST2 and ST3 treatments. However, the respective treatment doubles differed (p <0.05) from each other due to the behavior and similar conductivity values obtained during the entire composting process. In relation to the values of mesophilic bacteria, these did not present a significant difference (p> 0.05) for the analyzed treatments, unlike the thermophilic bacteria that presented a significant difference (p <0.05) in the ST4 treatment due to the stabilized behavior of the colony during the 126-day period. The values of germination index did not differ statistically (p> 0.05) throughout the composting process for the analyzed treatments, showing up to 42 days for treatments ST1, ST3 and ST4, and 62 days for treatment ST2. In this sense, the results indicate that composting is presented as an environmentally sustainable technology in the treatment and revaluation of organic waste, since the organic compounds produced meet the quality limits established in the current environmental legislation.