67 / 2025-04-15 15:30:01

Safety Assessment for Biogas Slurry Application of Anaerobic Fermentation from Pig Manure in Farmland

Manure；Anaerobic fermentation；Heavy metals; Safety assessment

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。

To explore the influence of different anaerobic fermentation times of pig manure on the main components of biogas slurry, samples of biogas slurry from the primary sedimentation tank, secondary sedimentation tank, and tertiary sedimentation tank of four large - scale pig farms in Hunan Province, as well as soil samples after biogas slurry irrigation were collected. The heavy metal concentrations, nutrients, and the number of parasites in the samples were detected and analyzed, respectively. The safety of the heavy metals toixc in soil were evaluated by using the Nemerow comprehensive index method. The results showed that the heavy metal concentrations in the biogas slurry decreased step-by-step with the extension of the anaerobic fermentation time. The total content of heavy metals in biogas slurry was Zn>Cu>Pb>Cd. After the application of biogas slurry, the concentrations of Zn, Cu, Pb, and Cd in the soils did not exceed the Risk Screening Values for Soil Contamination of Agricultural Land in the Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land (GB15618 -2018), and the contents of nutrient substances (including P and K) were increased significantly. In conclusion, after pig manure undergoes anaerobic fermentation and reaches the tertiary sedimentation stage, the heavy metals content in the biogas slurry is significantly decreased. The biogas slurry is rich in nutrients and has high safety , so it could be used for returinig to the fields.