添加腐熟污泥对生活垃圾堆肥氮素转化与损失的影响

Effect of adding mature sludge on nitrogen transformation and losses during refuse composting process

研究添加腐熟污泥对垃圾好氧堆肥过程中氮素转化与损失的影响,实验设置生活垃圾与腐熟污泥质量比分别为1∶1、2∶1和4∶1,以单独生活垃圾为对照,主要监测堆肥过程中固相(TN、氨氮、硝态氮和亚硝态氮)和气相(NH_3和N_2O)中氮素转化规律。结果表明:与单独生活垃圾相比,生活垃圾与腐熟污泥比例为1∶1和4∶1时,有机氮与TN损失明显减少;至堆肥结束4组堆体铵态氮与硝态氮相较于堆肥初期均有不同程度提高,其中4∶1组铵态氮与硝态氮提高最多,分别为32.3%和86.1%;亚硝态氮含量在整个堆肥过程中一直处于下降趋势;腐熟污泥的添加使物料堆肥过程中氨气和N_2O的释放量随着腐熟污泥添加量的增加而减小。总体而言,由于腐熟污泥对氨气良好的吸附性能和其含有的大量亚硝酸盐氧化菌,加入堆肥后减少反硝化途径N_2O的产生,从而减少生活垃圾堆肥过程中氮素损失和温室气体的释放。

In this paper,results are reported from a study on the effects of mature sludge on nitrogen transformation and losses during an aerobic composting process. Three mass ratios of MSW and mature sludge were set （1 ： 1,2： 1 ,and 4：1 ） ,and only a separate sample of MSW was used as control. We monitored the changing rules of nitrogen transformation in the solid phase （TN, NO3-N, NO2-N ,and NH3-N） and gas phase （NH3, N20）. The results indicated the following. 1 ） Compared with the control MSW, the losses of organic nitrogen and TN de- creased obviously when the ratios of MSW and mature sludge were 1 ： 1 and 4： 1. As composting progressed,the levels of ammonium nitrogen and nitrate nitrogen in the four composting groups increased by different degrees, compared to the early stage of composting, and the highest increase of ammonium nitrogen and nitrate nitrogen in the 4：1 group was 32.3% and 86.1% ,respectively. The nitrite content showed a downward trend during the whole composting process. 2） Adding mature sludge decreased the emissions of ammonia and N2O during the composting process,as the amount of sludge composting increased. Because mature sludge generally exhibits good adsorption and contains a large number of nitrite oxidizing bacteria （NOB） ,the N2O production from the denitri- fication pathway decreased after composting. This reduced the nitrogen loss and the release of greenhouse gases during the process of composting MSW.