Tratamento de águas residuárias da suinocultura em reator anaeróbio com pós-tratamento aeróbio/anóxico

Abstract

Swine farming is an important activity for the world economy, which is gaining prominence due to the large volume of waste produced, which is characterized by its high amount of organic matter, high concentration of nutrients, presence of heavy metals and pathogens. Once inadequately disposed of such wastes, they cause impacts on water resources, soil and air, besides promoting risks to human health. The joint removal of organic matter and nutrients from this type of residue has been a challenge. In this context, this research evaluated a process of biological treatment of swine wastewater for the simultaneous removal of carbonaceous matter, nitrogen and phosphorus in a system composed of an upflow anaerobic reactor and sludge blanket (UASB), followed by a Sequential Batch Reactor (SBR) operated in aerobic/anoxic cycles of 24 hours. The system was divided into two operational modules: (1) Sedimentation column, UASB and RBS, and (2) UASB and RBS. In module 1 two different steps were studied varying the reaction time and carbon source for denitrification and removal of phosphorus in RBS. In both modules, the UASB reactor, with a hydraulic detention time of 15.5 h and applied organic volumetric load of 5.6 kg/m³.day, reached average COD removal efficiencies of 76%. In step 2 of module 1, when methanol was added as an exogenous carbon source in the anoxic phase of the RBS (C/N ratio of 1.1), it was the one that presented the best performance, with global mean removal efficiencies of 78% 85% and 67%, for COD, total nitrogen and phosphorus, respectively.