城市生活垃圾和污泥混合堆肥中氮素变化规律研究

The change of nitrogenous components during the co-composting of municipal solid wastes and sludge

进行了不同比例的垃圾和污泥混合的高温好氧静态堆肥小试试验,主要研究了堆肥过程中全氮、氨氮、硝态氮、水溶性氮以及有机碳等的变化。结果表明,堆肥过程中有机碳、全氮和碳氮比呈下降趋势;堆肥产品中全氮与其初始浓度成正比,初始浓度越高,结束时全氮越高;碳氮比在整个堆肥过程中变化不大;氨氮的变化显著,堆肥23d,3种比例的混合样品(垃圾和污泥体积比分别为9∶1、5∶1和3∶1)中的氨氮分别由堆肥前的11.1、10.9、10.5g/kg下降到1.1、2.1、3.1g/kg;水溶性全氮和水溶性氨氮的下降趋势明显,水溶性氨氮是构成水溶性全氮的主要成分,堆肥前期温度的上升引起水溶性全氮和水溶性氨氮的迅速下降;硝态氮和水溶性硝态氮的浓度低,变化小;氮素损失主要在第3～10天的堆肥高温期,污泥量越大,氮素损失越严重,氮素损失率最高达45%。

Aerated static co-composting experiments were conducted at high temperature with various proportions of municipal solid waste and sludge, The major parameters studied were TN, NH4^＋-N, NO3^--N, TOC and water soluble nitrogen. The results indicated that all TOC, TN, C/N decreased. TN content of the composted products was proportional to the original TN content. The C/N ratio was down to about 15 at the end. The change of NH4^＋-N was significant： the NH4^＋-N contents of three mixed samples, 1# , 2# , 3# ,decreased to 1.1, 2.1, 3.1 g/kg from the original level of 11.1, 10.9, 10.5 g/kg respectively. Water soluble TN and NH4^＋-N dropped noticeably, and water soluble NH4^＋-N was the major compound of water soluble TN. The temperature rise during the initial stage caused water soluble TN to decrease abruptly. NO3^--N and water soluble NO3^--N were low and did not change significantly. The loss of nitrogen mainly occurred during the high temperature phase （3-10 days）. The loss of nitrogen was more pronounced when more sludge was added for composting. The loss reached up to 45%.