Valorización de residuos de la industria agroalimentariacodigestión de estiércol de vacuno lechero y suero de quesería

Abstract

This thesis consists of applying two wastes from the food industry (dairy cattle manure and cheese whey) to a series of treatment processes in order to investigate their efficiency in eliminating pollution and recovery of biogas, as well as obtaining a solid fraction, rich in nutrients. These treatments allow their valorization. Pretreatment processes were performed to separate the solid and the liquid fraction of the manure. The effect of whey percentage and the ratio gVSsubstrates / gVSinoculum on the methanogenic process stability and productivity was studied in batch at 35ºC. By running continuously at 35ºC in CSTR and UASB reactors, the maximum achievable OLR was 5.99 and 28.7 kg COD m-3 d-1 for HRT of 10.0 and 1.30 days and for percentages of whey of 65 and 60%, respectively. The volumetric production achieved under these conditions was 1.27 and 9.51 m3 CH4 m-3 d-1 in the CSTR and UASB reactor respectively. In the effluent NH4+ was recovered as struvite (MgNH4PO4). The solid fraction obtained after pretreatment was digested in batch under thermophilic conditions at 50ºC.