Codigestão anaeróbia de resíduos de frutas e verduras com água residuária da bovinocultura de leite

Abstract

Fruit and vegetable residues (FVR) makes up a large portion of organic waste, which, in turn, adds up to an expressive amount of urban solid waste collected in Brazil, and most of it does not receive adequate treatment. This fact can reduce the useful life of sanitary landfills and generate great problems. The supply centers (CEASA) daily discard a significant amount of FVR, and these residues can be used for energy and fertilizer production through anaerobic digestion (AD) process. However, given the characteristics of FVR, co-digestion (when two or more substrates are added) is one of the strategies that can make the process viable. Thus, the objective of this work was to study the anaerobic co-digestion of FVR with dairy cattle wastewater (DCWW), comparing with the monodigestion of both FVR and DCWW. Semi continuous tubular anaerobic reactors with a capacity of 60.0 L maintained at mesophilic temperatures, with a hydraulic retention time of 30 days, were employed and three treatments were evaluated with five replications in triplicate (T1: FVR, water and recycle; T2: FVR with DCWW in co-digestion and T3 only DCWW), which consisted of proportions (%) with progression of different loads of FVR (starting with 1, 1.5, 2, 2.5, 3% until 3.5% total solids – TS) in T1 and T2; in order to evaluate the effect of co-digestion on biogas and methane production potentials as well as on the quality of the biofertilizer when compared to monodigestion. Throughout the experiment, it was observed that the system responded to the positive progressions of 3.5% increase in TS, which increases the increase in biogas production. Therefore, anaerobic co-digestion is a relevant alternative for recycling energy and nutrients contained in fruit and vegetable residues and wastewater from dairy cattle.