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 agroindustrial waste. This study aimed to evaluate the biogas production (Pb) from the codigestion 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 Pb measured daily. Pb was higher at 36 °C for all mixtures compared to the psychrophilic condition (18 °C). Among the mixtures, the highest Pb value was observed for P3, reaching 0.34 and 0.60 m 3 biogas kg −1 CODremoved 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.

The feasibility of using biogas generated from livestock manure as an alternative energy source: A South African perspective

“…The mono-digestion and co-digestion of swine waste and laying-hen waste at various mixing ratios and temperatures were assessed in a study by Pereira et al (2023). A co-digestion ratio of 25:75 swine waste to hen waste produced more biogas than the other ratios when COD was removed at temperatures of 18 and 36 °C, respectively, generating 0.34 and 0.60 m 3 per kilogram of COD removed.…”