Partida sob condições de alta carga e operação de um reator UASB tratando água residuária de suinocultura: desempenho, balanços de massa e diversidade microbiana

Abstract

This work aimed to contribute to the knowledge about the starting and operation of up-flow anaerobic sludge blanket (UASB) reactors treating swine wastewater (SWW) under high organic loading rate (OLR) and low hydraulic retention time (HRT). Before inoculation, a specific methanogenic activity (SMA) test was carried out with the inoculum sludge. The mean values of 0.01 and 0.06 kgCODCH4 kgSTV-1 d-1 were obtained, using a mixture of volatile fatty acids (VFA) and glucose as substrates, respectively. However, in order to start up under high load conditions, the reactor started with biological organic loading (BOL) of 0.7 kgCOD kgTVS-1 d-1, OLR of 10.4 ± 0.9 kgCOD m-3 d-1, hydraulic loading rate (HLR) of 0.75 m3 m-3 d1 , HRT of 12 h and an ascending speed of 0.14 m h-1. The removal efficiencies of BOD520 °C and COD throughout the experiment were in the order of 74,94 and 76,31%, respectively. The removal efficiencies of total solids (TS), total volatile solids (TVS) and sedimentable volatile solids (SVS) were, on average, in the order of 53, 61 and 80% in the stationary phase. The methane content in the biogas produced was 66.13%. The microbiological analysis carried out on the sludge found the predominance of microbial groups, according the literature, usually found in system treating SWW, as the phyla Firmicutes and Bacteroidetes. To conclude, the UASB reactor is stable during the treatment of SWW and operating under high OLR. However, further studies are recommended for a better understanding of anaerobic digestion in reactors with high OLR.