| Being an advanced treatment of domestic wastes, Semi-aerobic Landfill was installed leachate collecting canals with slack flow. Owing to the loading with oxygen from air through the particular canals, relatively rapider aerobic degradations were occurred in some zones in the Semi-aerobic Landfill,so as to the ammonia level was deceased greatly. However, little information was available for the degradation mechanism in the Semi-aerobic Landfill, especially in the nitrogen transformation, which was of significance from better design the landfill so as to control the nitrogen pollution from sources and thus was imperative and critical. The thesis discussed temporal and spatial distributions of nitrogens levels in semi-aerobic landfill structure in contrast with aerobic landfill structure, so understanding the basic rule of the nitrogen transformation in Semi-aerobic landfill structure.By virtue of their working ways, two small-scale simulative devices of the Semi-aerobic Landfill and the Anaerobic Landfill were constructed. Three studied transects and their sampling sites were arranged according to KRIGING principles on the two landfills respectively. In this study, the concentrations of CODcr,BOD5,TN,NH3-N,NO3-N and NO2-N as well as pH values were determined regularly according to the degradation of wastes. Based on these, temporal and spatial distributions of nitrogen levels along with nitrogen transformation were investigated. The results showed that there were rapid and smooth decline of the CODcr concentrations in leachate in the upper-layer, middle-layer and under-layer of Semi-aerobic Landfill within seven week, which decreased 85.1%, 75.4% and 51.5% of origination respectively. After that, the decrease of CODcr levels in leachate turned slowly. In semi-aerobic Landfill, the difference of CODcr levels of three transects was significant, which was lined with under-layer＞middle-layer＞upper-layer. In the Anaerobic Landfill, there were not significant differences of CODcr concentrations in leachate in three transect. In comparisons to Semi-aerobic Landfill, the CODcr levels in the three transect were relatively higher in Anaerobic Landfill.Meanwhile, the TN concentration in the leachate was found to be decrease smoothly in the upper-layer in Semi-aerobic Landfill, which reduced 88.59% of origination. In comparison to upper-layer, however, the decreases were found to be slow in the leachate in the middle-layer and under-layer in Semi-aerobic Landfill, which decrease 70.8% and 61.7% of origination, respectively, In the Anaerobic Landfill, slow decreases and jumping fluctuations of TN concentrations in the leachate were investigated in the three transects. For the dynamics of NH3-N levels in the leachate, the levels in upper-layer, middle-layer and under-layer were decreased from 284.66 mg L-1, 2154.77 mg L-1and 3018.81 mgL-1 in the origination to 45.16 mg L-1, 163 mg L-1and 1441.32 mg L-1 within 27 week, respectively. Comparatively, the declines of NH3-N concentrations in the three layers in the Aerobic Landfill were not significant. On the other hand, the differences of the dynamics of NO3-N levels in the leachate were compared in this study. In the Semi-aerobic Landfill, the NO3-N concentrations in the leachate were lower in upper-layer than those in the middle-layer and under-layer within the first 15 weeks. After 15weeks, however, there was rapid increase of NO3-N levels and up to 68.15 mg L-1 in the leachate in the upper-layer at 27 week, which exceeded the NH3-N levels and reflected that much of NH3-N probably changed into NO3-N. Also, the differences of the NH3-N levels in the leachate were not significant in middle-layer and under-layer. In the Aerobic Landfill, there was a decrease trend of NH3-N levels in upper-layer, while those were kept steady in the middle-layer and under-layer. In this study, the accumulations of NO2-N were found both in the Semi-aerobic Landfill and Aerobic Landfill, which was slightly higher in Semi-aerobic Landfill.This study showed that there was a significant positive correlation between NO3-N contents and NH3-N levels (p＜0.01) in the leachate in the upper-layer in Semi-aerobic Landfill, but not in the middle-layer and the under-layer, which was possibly explained by stronger nitration in the upper-layer with sufficient oxygen than that in other layers. Further analysis of nitrogen levels in the leachate demonstrated that the content of NH3-N correlated strongly with the concentrations of TN the middle-layer and the under-layer (p＜0.01, p＜0.01, respectively); but not in the upper-layer. This indicated that the change of NH3-N dominated the dynamic of TN in the middle layers and under layers in the Semi-aerobic Landfill.Spatial differences of the levels of TN and NH3-N in the leachate were found to be significant both in the Semi-aerobic Landfill and in the Aerobic Landfill, which were lined with under-layer＞middle-layer＞upper-layer. In the Semi-aerobic Landfill, moreover NO3-N concentrations in the leachate were much higher in upper-layer than those in the two lower layers. At the same time, the spatial differences of NO3-N concentrations were found to be not significant in the Aerobic Landfill. In this study, variance of NO2-N levels in different layers were observed to be not significant both in the two landfills. Furthermore, Variation coefficients of the levels of TN and NH3-N in the leachate were found to be small in every layer in the two landfills, while those of NO3-N and NO2-N were relatively large.
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