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ABSTRACT:The agro-industrialization of animal products has led to a significant waste generation, which has been stabilized by composting process in specialized plants. Waste stabilization time on composting depends on the handling used. 12 treatments were performed, three frequency turnings combined with two environmental conditions (with and without coverage of the composting area) and with and without commercial inoculant, whose results were submitted to multiple regression analysis. Windrows turned twice a week in the first month had adequate temperature control and stabilization time of 83.5 and 95.5 days for uncovered and covered windrows, respectively. Uncovered windrows have accelerated the process in 10 days on average, with the disadvantage of increasing nutrient losses. The weekly inoculation of Bacillus (subtilis, licheniformis and polymyxa) and Yarrowia lipolytica had no significant effect (p≥0.05).

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ABSTRACT:The growing demand for animal protein is directly related to the feedlot system of animals and their assumptions, such as the waste management. The characterization of the final products becomes an important factor in decision making by one or by other process. The objective was highlight characteristics that fertilizers present due to the used of stabilization process, by the principal component analysis. For the manure stabilization we realized three aerobic processes, composting, vermicomposting and natural decomposition, and one anaerobic, the anaerobic digestion. These processes produced the compost, the vermicompost, the decomposed manure and the biofertilizer. Fertilizers produced were analyzed by means of seventeen chemical and physicchemical parameters. The main differences are related to stability and organic matter content. The compost is more stable fertilizer and decomposed manure is the worst. The vermicompost is presented as the best option to adsorb cadmium and lead. The biofertilizer has the lowest values of pH, CEC and adsorptive capacity of heavy metals (Cd and Pb). The decomposed manure in presence of precipitation, and the vermicompost, with significant irrigation, generates fertilizers with smaller source of potassium.

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The recovery of waste from the broiler production chain (BPC) is consistent with the principles of a circular economy. Besides turning waste into organic compost, its use as substrate for the production of vegetable seedlings further increases its economic value. However, it is necessary to adapt its characteristics to enable its use as substrate. To this end, the addition of boiler remnant charcoal wastes (BCW), another type of waste generated in the BPC, to the organic compost resulting from the composting of BPC waste with different bulking agents (BAs) was studied. The addition of BCW to agro-industrial compost reduced the electrical conductivity (EC) of substrates. Multiple linear regression showed that, of the 13 variables (physical, chemical and physicochemical) studied, three (EC, pH and N content) are sufficient to explain the seedling quality index (SQI). Simple nonlinear regression showed that, in order to achieve higher SQIs and easier removal of clod from tray, an additional 30% in weight of BCW is required for compost, using urban tree pruning, wood sawdust and sugarcane bagasse BAs. The use of cotton and Napier grass waste as BAs is not recommended for BPC waste mixtures, as they cause a large increase in substrate EC.