The objective of this study was to evaluate the process of anaerobic digestion treatment of poultry slaughterhouse wastewater, considering hydraulic retention time (HRT) of 7, 14 and 21 days, plus the addition of lipolytic enzyme to the substrates at concentrations of 0; 0.5; 1.0 and 1.5 g L-1 charge added to the digesters. The influence of HRT and the addition of lipolytic enzyme to the substrates was evaluated by biogas production and CH4 production potentials for COD (chemical oxygen demand) added and removed as well as by reductions in the levels of COD, concentrations of N, P and K and pH values. The results showed that there was influence of HRT (HRT 7 in which the expressed best results, average weekly production of biogas with 40.7 L-1 and 32.2 L-1 CH4) and concentrations of enzymes with higher production values to treatments 1.0 (24.6 L) and 1.5 g L-1 (26.2 L), which did not differ. The enzyme concentrations of 1.0 and 1.5 g L-1 showed the largest potential for biogas production (1.1 and 1.1 g L-1 of COD added, respectively) and methane (0.9 and 0.8 g1 L COD added, respectively), compared with 0.5 g L-1 (0.8 and 0.7 g L-1 biogas and CH4 respectively) and 0 g L-1 (0.7 and 0.5 g L-1 biogas and CH 4, respectively). The highest COD removals were achieved at concentrations of 0.5 g L-1 (83.3%) and HRT of 21 days (74.4%). However for there to be a more efficient energy recycling, it is recommended to use concentrations of 1.0 g L-1 effluent and hydraulic retention time of seven days.
Bio-fertilizer; chemical oxygen demand; broiler slaughterhouse effluent; methane
