Determination Of Methane Generation Potential And Evaluation Of Kinetic Models In Poultry Wastes

Abstract Brazil is considered the second largest producer of poultry in the world. In this production chain, poultry litter represents the main by-product (waste) generated, which can cause environmental impacts if they are disposed of improperly. Anaerobic digestion can be used as a treatment converting waste into biogas (energy/heat) and biofertilizer. The aim was evaluated the kinetics of the methane generation potential of chicken (Gallus gallus domesticus) and quail (Coturnix coturnix) litter. The Biochemical Methane Potential was evaluated in batch reactors of 250 mL, under mesophilic conditions (37 ± 2°C) and agitation (60 rpm) for 47 days. Two anaerobic sludges (granular and flocculent) were used with alkaline supplementation (1g NaHCO3). A low C/N ratio (4.66 - 10.87) of the substrates (poultry litter) was observed, which can interfere with anaerobic digestion due to ammonification in the reaction medium and bacteriostatic effects, reducing methane production. The biogas generated showed average concentrations of 54%, reaching a maximum of 67%. Biogas production reached 80% of the maximum (accumulated volume) in 30 days and the highest average methane potential was observed for the chicken litter residue, with 101.4 NmL.g-1 VS using granular anaerobic sludge. The modified Gompertz model obtained the best adjustments for the substrates and applied experimental conditions. Anaerobic digestion is recommended for energetic valorization of poultry residues.