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污染控制技术及原理

Nitrogen transformation and loss during the composting of food wastes with different nitrogen contents

基金项目：国家高技术研究发展计划(863)项目(No.2001AA644020);国家重点基础研究发展规划(973)项目(No.2005CB724203)

摘要：采用静态好氧工艺研究了含氮量分别为32.4g·kg^-1、45.3g·kg^-1和58.2g·kg^-1的厨余垃圾(N₀、N₁、N₂)与木屑混合堆制时,堆肥过程中不同形态氮的转化及其氮损失规律.结果表明,堆肥中堆体全氮含量呈先升后降趋势,部分有机氮转化为铵氮导致堆体pH升高,在通风和高温的联合作用下,NH₃挥发出堆体造成一定的氮损失.随着底物含氮量的增加,NH₃挥发速率和氮损失率均呈上升趋势.堆肥结束时N₀、N₁、N₂的堆体全氮含量分别下降了16.4%、26.3%和21.7%,NH₃累计挥发量分别为7.0g·kg^-1、9.8g·kg^-1和29.4g·kg^-1,堆肥氮损失率分别为35·0%、49.9%和53.0%.NH₃挥发主要集中在高温阶段的中后期,是厨余堆肥氮损失的主要原因.

Abstract：This study investigated nitrogen transformation and loss during the composting of food wastes with added sawdust. Three kinds of food wastes (defined as N₀, N₁ and N₂) were used, containing 32.4g·kg^-1, 45.3 g·kg^-1 and 58.2 g·kg^-1of nitrogen. An aerated static pile compost system was employed to compost the food wastes. The results showed that total nitrogen in the compost first increased and then decreased. Part of the organic nitrogen was transformed into ammonium and which resulted in increased pHof the composting pile. Under the combined effect of high temperature and ventilation, ammonia volatilization from the pile led to nitrogen loss. As the nitrogen content in the food wastes increased, the rate of ammonia emissions and amount of nitrogen loss from the pile was also enhanced. At the end of composting, the accumulated ammonia emissions from all three food wastes, N₀,N₁ and N₂, were 7.0g·kg^-1, 9.8 g·kg^-1 and 29.4 g·kg^-1, respectively. The content of total nitrogen decreased by 16.4%, 26.3% and 21.7%, respectively. The lost amount of nitrogen was 35.0%, 49.9%and 53.0% of the initial total nitrogen amount.Most ammonia volatilization took place in the intermediate and later composting phases at high temperature. Nitrogen losses were attributed mostly to ammonia volatilization.

Key words：ood wastes composting nitrogen transformation ammonia volatilization