农业废弃物厌氧发酵及沼肥利用全过程碳氮变化研究

Carbon and Nitrogen Changes in the Whole Process of Agricultural Waste Anaerobic Fermentation and Its Residue Utilization as Fertilizer

厌氧发酵是实现农业废弃物资源化利用、改善生态环境的重要途径。文章系统综述了农业废弃物厌氧发酵及沼肥利用过程碳氮元素变化,为减少沼肥养分损失提供参考依据。分析结果发现,湿法发酵-沼液储存全过程碳氮元素损失分别达15.52%~29.45%和4.94%~29.79%,其中发酵阶段分别损失15.40%~27.29%和4.19%~13.16%,储存阶段分别损失2.94%~29.63%和4.50%~37.31%;干法发酵-沼渣堆肥全过程碳氮元素损失分别达38.79%~49.38%和18.76%~50.13%,发酵阶段分别损失7.6%~16.72%和1.20%~8.30%,堆肥阶段分别损失33.75%~35.01%和19.15%~42.34%。总体来看,湿法发酵-沼液储存过程碳氮损失小于干法发酵-沼渣堆肥过程,更有利于节能环保;储存阶段氮损失大于碳损失,应采用加盖低温储存方式减少氮损失;堆肥阶段碳含量降低,应注意调节适宜的含水率和通风供氧等条件减少碳损失,提高堆肥养分含量。

Anaerobic fermentation is an effective way to realize the resource utilization of agricultural residues and improve the ecological environment. This paper expounded the changes of carbon and nitrogen during the whole agricultural waste anaerobic fermentation process and its biogas residue utilization as fertilizer, providing reference for reducing nutrient loss for biogas fertilizer. The results showed that, the total losses of carbon and nitrogen were 15.52% - 29.45% and 4.94% - 29.79% respectively in the whole process of wet fermentation and biogas slurry storage, in which the fermentation stage lost 15.40% - 27.29% and 4.19% - 13.16%, the storage stage lost 2.94% - 29.63% and 4.50% - 37.31% respectively; the whole process of dry fermentation and biogas residue composting totally lost carbon and nitrogen 38.79% - 49. 38% and 18.76% - 50. 13% respectively, in which the fermentation stage lost 7.6% - 16.72% and 1. 20% - 8. 30%, the composting stage lost 33.75% - 35.01% and 19.15% -42.34% respectively. In overall, the wet fermentation with slurry storage process lost less carbon and nitrogen nutrients than that of dry fermentation with residue composting. And during the storage stage the nitrogen loss was higher than carbon loss. It was suggested that the low temperature storage with cover should be applied to reduce nutrient loss. For the composting stage, appropriate moisture and ventilation should be adjusted to reduce carbon loss and improve the nutrient content of compost.