Co-digestão anaeróbia dos dejetos de ovinos com diferentes inclusões de resíduo líquido de incubatório

Abstract

The objective this work was to determine optimal levels of inclusion of liquid hatchery (HR) in sheep manure in the process of anaerobic co-digestion, in different hydraulic retention times- HRT. The parameters evaluated were: total and specific productions of biogas and methane, reductions of total solids, volatile solids, reduction of chemical oxygen demand, neutral detergent fiber, nitrogen contents, ethereal extract and pH. The largest TS reductions observed were 66.66; 69.75 and 73.82%, with inclusion of 12.03; 13.04 and 12.76% of HR in HRT of 12, 17 and 22 days, respectively. The inclusion of the doses of 14.78; 14.43 and 12.65% HR provided the greatest COD reductions, which were 55.71; 58.00 and 60.59% in HRT of 12, 17 and 22 days, respectively. There was a significant effect between reductions of NDF and HRT, with reductions of 45.73% and 44.36% with HRT of 22 and 17 days, respectively. The 22 day HRT presented the highest specific biogas production of 507.20 L Kg-1 TS with the inclusion 9,81% HR and 652.47 L Kg-1 VS with the inclusion of 9.71% HR. The maximum specific methane yields by TS were 195.18; 263.68 and 271.31 L Kg-1, with HR inclusions of 9.80; 10.92 and 10.55% in HRT of 12, 17 and 22 days. The codigestion of sheep manure with different HR inclusions promoted reduction of solid and fibrous constituents, increasing the production of biogas and methane.