MITIGAÇÃO DA PERDA INICIAL DE N NA COMPOSTAGEM DE RESÍDUO DE ABATEDOURO COM USO DE ADITIVOS

The aim of this paper was to evaluate the effect of biochar and crude glycerin in composting with slaughterhouse residue to reduce N losses in aerated static piles in the initial composting period. A mixture of bovine and swine slaughterhouse residues was made and associated with straw in the proportion of 3:1 of fresh mass. It was adopted a completely randomized design, five treatments (without addition, 5 and 10% of biochar and 5 and 10% of crude glycerin) and 3 repetitions. The repetitions were formed by TNT bags with a capacity of around 1 kg of substrate, which were placed inside static piles between the waste layer and straw. Collections were made every 5 days for up to 20 days. Aeration was performed with a PVC pipe with a flow of 0.6 L.min-1. The additives were efficient in retaining N from the analyzed period. The biggest losses occurred in the first 5 days. All inclusions were efficient in retaining N, however 10% crude glycerin was the condition with the least accumulated loss (18.8%) at the end of the analyzed period. It is concluded that additives can be used to retain N even with material rich in N as the slaughterhouse.