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 (Pb) 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 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 m3 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.摘要：厌氧消化（Anaerobic Digestion, AD）是农业工业废弃物降解处理的主流路径之一。本研究旨在评估不同温度条件（嗜冷与中温）下，猪粪（SW）与蛋鸡粪便（LHW）厌氧共消化的沼气产率（Pb）。实验采用实验室规模的批次发酵体系，于容积1.25 L的厌氧反应器中开展，运行周期为60天。实验设置3组体积占比（%）分别为25/75（P1）、50/50（P2）及75/25（P3）的猪粪/蛋鸡粪便混合基质。分别在18℃（嗜冷条件）与36℃（中温条件）下，对厌氧消化前后的混合基质开展总固体（Total Solids, TS）、挥发性固体（Volatile Solids, VS）及化学需氧量（Chemical Oxygen Demand, COD）表征，并每日监测沼气产率。结果表明，所有混合基质在36℃中温条件下的沼气产率均高于18℃嗜冷条件。各组混合基质中，P3组的沼气产率最高，在18℃与36℃条件下分别可达0.34与0.60 m³沼气·kg⁻¹ 去除COD。厌氧消化后，P1、P2、P3三组沼渣的微量与常量营养元素含量均有所提升，表明其具备农用资源化利用潜力。综上，猪粪与蛋鸡粪便的厌氧共消化在废弃物管理与沼气能源回收方面具备良好应用前景，尤其在蛋鸡粪便占主导的混合基质的中温发酵条件下优势突出。