生活垃圾堆肥浸提液组成及其演化规律

堆肥浸提液与渗滤液组成相似,研究生活垃圾堆肥浸提液组成与演化特征可以为堆肥过程污染控制和堆肥质量改善提供科学依据。通过基本理化指标和三维荧光光谱分析,研究了生活垃圾堆肥浸提液的组成和转化特性。结果显示,在堆肥一次和二次发酵过程中,浸提液pH由5.43上升至9.24,无机阴离子无显著变化,电导率(EC)稳定在7.50 mS/cm上下波动,ORP为正值,总氮从611.08 mg/L下降至177.43 mg/L,NH4+-N和NO3--N浓度变化不明显,NO2--N从未检出到后期达10.28 mg/L,有机氮从246.64 mg/L下降至172.52 mg/L。溶解性有有机物含量(DOC)从7 419.00 mg/L降至5 569.00 mg/L,其中的有机物发生降解和转化,生成胡敏酸和富里酸等物质。浸提液中重金属Fe、Cd、Cu、Zn、Cr、Mn、Ni和 As浓度升高。通过研究发现,在堆肥中添加木屑等填料可以降低浸提液中NH4+-N的浓度,具有除臭作用,同时对pH值、EC和ORP均有调节作用,能提高堆肥的土地可利用性。

Composition and transformation of composting leachates from municipal solid wastes

In order to provide scientific evidence for controlling pollution in composting process and improve compost quantity, the composition and evolution of composting extractible liquid, which similar to leachates, were studied based on the basic of physicochemical characteristics and three-dimensional excitation-emission matrix fluorescence spectroscopy (3DEEM). The results showed that pH value increased from 5.43 to 9.24, while the concentrations of EC, F-, Cl-, SO42- changed insignificantly and ORP kept positive with increasing composting time. It also showed that the NH4+-N and NO3--N concentrations changed insignificantly, NO2--N content showed an increase trend, Org-N content decreased from 246.64 mg/L to 172.52 mg/L, and TN content decreased from 611.08 mg/L to 177.43 mg/L with increasing composting time. The content of dissolved organic matter decreased from 7419.00 mg/Lto 5 569.00 mg/L, and protein-like substance were degraded while humic-like substance including humic and fulvic acids were produced. During the composting process, the Fe, Cd, Cu, Zn, Cr, As, Mn and Ni concentrations in extractible liquid exhibited an increase trend. The results also showed that fillers, which were added in the late composting stage, could be used as deodorant by reducing the concentration of volatile ammonium nitrogen in extractible liquid. At the same time, fillers can also adjust to pH, EC and ORP result to improve fertilizer fertility and enhance bioavailability.