4种畜禽粪便厌氧发酵产甲烷特性研究

本文采用玻璃厌氧发酵罐研究了猪粪、牛粪、鸡粪和鸭粪在室温下发酵20 d过程中产甲烷气量及其受物料特性影响的规律, 为动物废弃物的资源化利用提供指导。研究表明, 在同等条件下猪粪、牛粪、鸡粪和鸭粪经过20 d的厌氧发酵后, 总产气量从大到小排序为牛粪>鸭粪>猪粪>鸡粪, 分别为2 649 mL、2 515 mL、1 964 mL、1 278 mL; 与总产气量排序相似, 上述粪便厌氧发酵总固体物质降解产气率分别为47.60 mL·g^-1、45.23 mL·g^-1、37.27 mL·g^-1和33.49 mL·g^-1。猪粪在厌氧发酵过程中易发生酸化, 第10 d发酵液 pH降到5.62, 从而导致产气量下降; 鸡粪在厌氧发酵过程中铵态氮含量过高, 发酵液铵态氮含量在前5 d就快速增长, 第15 d达到最大值3 604 mg·L^-1, 从而抑制产气。可见, 源于物料自身的pH和铵态氮含量变化是影响畜禽粪便发酵液厌氧产气的重要因素。

Methane generation during anaerobic fermentation of four livestock slurries

In order to promote livestock slurry recycling, the characteristics of methane generation from pig manure, cow dung, chicken dung and duck dropping during anaerobic fermentation were analyzed by using glass anaerobic fermentation equipment. On specific dates, the methane volume, pH and ammonia nitrogen content of fermentation liquid were measured within 20 days. The results show that after 20 days fermentation, total generated methane from cow dung, duck dropping, pig manure, chicken dung is respectively 2 649 mL, 2 515 mL, 1 964 mL and 1 278 mL. The volume of methane generated from per unit total solids is respectively 47.60 mL·g^-1, 45.23 mL·g^-1, 37.27 mL·g^-1 and 33.49 mL·g^-1. Pig manure prone to acidification during anaerobic fermentation, pH of fermentation liquid decreases to 5.62 at the first 10 days, thereby reducing methane generation. For the chicken manure under anaerobic condition, methane generation weakens with increasing ammonia nitrogen. It is therefore concluded that both pH and ammonia nitrogen soured by fermentation of raw materials are the key factors influencing methane generation of livestock slurries.