27 / 2025-03-30 21:01:04

Enhancing livestock wastewater psychrophilic treatment through a multi-stage anaerobic reactor (MAR) integrated with biochar

Psychrophilic anaerobic digestion,Direct interspecies electron transfer,Stage separation,Biochar,Multistage anaerobic reactor (MAR)

5.减污降碳与废弃物利用 > （5）畜禽废弃物处理技术：好氧发酵集成技术、卧床垫料再生技术、异位发酵床集成技术、储存发酵集成技术、厌氧发酵集成技术、粪肥制备集成技术、固体粪肥施用技术、液体粪肥施用技术、环境控制集成技术、区域集中处理技术。

Psychrophilic anaerobic digestion (AD) is an effective strategy for treating wastewater in cold regions, but the metabolic inhibition caused by low temperatures remains a critical challenge. In this study, the enhancement mechanism of two types of biochar (pyrochar and hydrochar) on AD under a temperature gradient (15℃-35℃) were studied. Biochar could enrich functional microbial to regulate methane production (4.11%-41.16%) under low temperature stress. Hydrochar accelerated the acidogenisis by releasing organic matter through its incomplete carbonized structure. Pyrochar increased electroactive bacteria (Bacteroidetes_vadinHA17 and Petrimonas) to promote acetogenesis and methanogenesis via conductive structure-mediated direct interspecies electron transfer (DIET). The redundancy analysis and structural equation model further confirmed that the short-term enhancement of hydrochar and the electron transfer reinforcement of pyrochar, respectively. Further, a novel multi-stage anaerobic reactor (MAR) integrated with pyrochar was exploited to enhance psychrophilic AD process (35℃-5℃). MAR optimized the microbial community structure in distinct zones through stage separation and pyrochar introduction, thereby reducing temperature shocks to methanogens, balancing methanogenesis pathways, and promoting the establishment of DIET, ultimately maintaining a stable methane production rate (>75% organic carbon removal) above 10℃. This study hopefully provides theoretical support and reactors for optimization of wastewater AD in cold regions.