Efluente de abatedouro avícola: processos de biodigestão anaeróbia e compostagem

Abstract

The aim of this work was to evaluate the efficiency of anaerobic biodigestion on treatment of broiler slaughterhouse effluent. The experiment was carried out in the Laboratory of Benefit of Waste from Animal Production, where 8 semi-continuous experimental biodigesters were processed according to the treatment of time of hydraulic retention time (HRT) (7, 14, 21 and 28 days) and separation of the solid fraction (with sieve with 1mm and without sieve) during 4 weeks (replication). Average of weekly production of biogas and methane, concentrations of methane were evaluated, as well the potentials of production per quantity of chemical demand of oxygen (CDO) that was added or reduced, besides the concentrations of N, P and K in the beginning and the end of the process, most probably number of total and thermotolerant coliforms were also evaluated. For analysis of data, the complete randomized design in 4 x 2 (4 HRT: 7, 14, 21 and 28 days and the use or not of sieve) factorial scheme in sub-divided plots in time were used. Regarding to obtained results, when productions of biogas and methane were evaluated, it was verified that there was significant difference (P<0,05), which the highest productions were reached by HRT of 7 and 14 days (5,29 and 2,38 ℓ of biogas and 4,28 and 1,73 ℓ of methane, respectively). There was interaction between HRT and separation of solid fraction, which the greatest production was obtained without separation. Similar behavior was observed with potentials of production, with maximum potential of 0,41 m3 methane.kg-1 CDO added to HRT of 7 days without separation of solid fraction. It was concluded that the separation of solid fraction is not recommended in pre-treatment of broiler slaughterhouse effluent, since the use of that reduced the productions and the potentials of biogas and methane.