ANAEROBIC CO-DIGESTION OF SWINE AND LAYING HEN WASTE FOR BIOGAS GENERATION AND DIGESTATE QUALITY

ABSTRACT

Anaerobic digestion (AD) stands out as a degradation pathway for the treatment of agro-industrial waste. This study aimed to evaluate the biogas production (P_b) from the co-digestion of swine (SW) and laying hen waste (LHW) under different temperature conditions (psychrophilic x mesophilic). The studies were carried out on a laboratory scale in anaerobic reactors (1.25 L) in a batch system for 60 days. Three mixtures in volumetric proportions (%) of 25/75 (P1), 50/50 (P2), and 75/25 (P3) (SW/LHW) were studied. The mixtures were characterized before and after AD in terms of TS, VS, and COD under temperatures of 18 and 36 °C, with P_b measured daily. P_b was higher at 36 °C for all mixtures compared to the psychrophilic condition (18 °C). Among the mixtures, the highest P_b value was observed for P3, reaching 0.34 and 0.60 m³ biogas kg⁻¹ COD_removed for 18 and 36 °C, respectively. The digestate showed an increase in the contents of micro-and macronutrients for P1, P2, and P3 after AD, which indicates its use for agricultural purposes. The co-digestion of swine and laying hen waste is a promising proposal in terms of management and energy recovery of biogas, especially for mesophilic conditions in mixtures with a predominance of laying hen waste.

anaerobic digestion; resource recovery; mesophilic; psychrophilic