连续流强制通风槽式污泥堆肥工艺的温室气体和氨气排放特征

我国污泥堆肥过程中温室气体(CH4、N2O)和氨气(NH3)排放的基础数据十分缺乏.本研究以连续流强制通风槽式污泥堆肥工艺为对象,通过现场试验和观测,考察不同操作参数下堆肥过程中温室气体和氨气的排放特征.结果表明,减小辅料投加比例不利于有机质的转化(试验组和对照组的有机质降幅分别为1.38%、8.85%),较低的C/N比虽小幅增加了氨气的排放量(高于对照组8.68%),却有助于减少总氮损失(试验组16.1%、对照组21.8%),并可减少污泥堆肥过程的温室气体排放(以eCO2/DC计,试验组为1.70 g·kg-1、对照组为2.85 g·kg-1).采用"初期降低,末期升高"的通风方式,尽管增加了污泥堆肥过程中温室气体排放的CO2当量(高于对照组55.1%),却减少了氨气累积排放量(试验组66.86 g·m-2,对照组72.04g·m-2),进而降低了总氮损失(为对照组的51.34%).

Emissions of Greenhouse Gas and Ammonia from Sewage Sludge Composting by Continuous Aerated Turning Pile

There is a lack of observation data on greenhouse gas (GHG) and ammonia emissions from sewage sludge composting, though the emissions can result in environmental issue and nitrogen loss. In this study, GHG and ammonia emissions were monitored under different operating parameters during sludge composting with continuous aerated turning pile at full scale. Results illustrated that the reduction of amendment addition could result in low organic matter transformation (1.38% and 8.85% for the test group and the control group, respectively). Though low C/N ratio might slightly increase the ammonia emission (8.68% higher than the control group), it was helpful to reduce both GHG emission (1.70 g·kg^-1 DC for the test group and 2.85 g·kg^-1 DC for the control group, respectively) and total nitrogen loss (16.1% and 21.8% for the test and control groups, respectively). Through applying an aertion strategy in which the airflow rate was lower in the beginning and higher in the end of sludge composting, a higher GHG emission and a lower ammonia emission were observed in the test group, e. g., 55.1% higher of GHG emission than the control, and 66.86g·m^-2 and 72.04g·m^-2 of ammonia emission in the test and the control, respectively. And a good conversation of total nitrogen thus occurred in the test as a result of such aeration strategy, with only 51.34% of TN loss as compared to the control.