粪便生态厕所高温好氧堆肥过程中气态氨的释放特性

Emission of gaseous ammonia in aerobic thermophilic composting of human feces

粪便好氧堆肥过程中氮元素的损失问题主要是氨气NH3释放,是关乎堆肥产物肥效的重要问题.实验设计小型密闭好氧堆肥反应器,进行了一系列的批实验,研究粪便高温好氧堆肥过程中NH3释放的特性.结果:在高温堆肥时,累积的氨态氮NH3-N的增加主要发生在堆肥第1 d,总量达到约0.81g.NH3-N释放速率呈现出先迅速增加之后迅速减少并接近环境背景的两个阶段.NH3释放与氮的迁移转化密切相关,氮的迁移转化也主要发生在堆肥的第1d.总氮Ntot损失约17%(约0.90g),主要是无机氮Nino的迅速减少(约0.89g),有机氮Norg几乎没变.Nino中的铵态氮NH4+-N(占无机氮94%以上)迅速减少,亚硝态氮NO2--N几乎消失,硝态氮NO3--N增加量与NO2--N减少量持平.物料衡算说明氨气挥发是氮损失的主要原因,且主要集中在堆肥初期.NH3挥发量主要取决于NH4+-N浓度和温度.高温加快了NH4+-N挥发,使得NH3-N释放时间缩短、总量小、较为集中.高温抑制了Norg氨化,减少了NH4+-N的生成,减少了NH3挥发,最终氮的损失减少.研究表明:高温虽然加快了NH3的挥发,但抑制了Norg氨化,使得总的NH4+-N挥发减少,氮的损失减少.NH3挥发是氮损失的主要原因,高温时在堆肥初期(第1d)控制好NH3挥发是控制氮损失的有效阶段1.

There is a nitron loss as gaseous ammonia was exhaused from aerobic composting of human feces,showing how important emission of gaseous ammonia was in composting.Batch experiments were conducted using a closed aerobic composting reactor with sawdust as the bulky matrix to simulate the condition of a bio-toilet for sanitary disposal of human feces.Attention was paid to the characteristics of emission of gaseous ammonia under the thermophilic condition.The results indicated that merely 17% fecal nitrogen loss（iNorganic nitrogen Nino,mainly NH＋4-N） was observed in a two-week composting period during aerobic thermophilic composting at 60℃.Concentration and rate of ammonia increased quickly first,reached maxium,then decreased and reached zero almostly finally,and accumulation of ammonia increased quickly first,and then increased gradually to an constant amount finally（firstly 1 day） at 60℃.This shows that： the emession of ammonia was an important way for nitrogen loss at the initial stage of compost.Ammonification of Norg may have been hindered and emmission of NH＋4-N accelarated under the thermophilic condition.As a result,nitrogen loss was controled at the initial stage of compost and thermophilic composting can be considered as a method to improve the nitrogen retaining property of the compost.