We confirm whether Zr powders can restrain a rapid nitrification reaction and offer a stable oxidation reaction according to temperatures in nitrogen gas purification. A pellet-type, porous Zr getter is prepared (diameter: 10 and thickness: 3 mm) using Zr powder with an average particle size of 45 μm. While maintaining the whole system, the Zr getter reaction is confirmed with an increase in temperature from 150 to 550 oC at increments of 100 oC under 99.999 % purity nitrogen atmosphere comprising of 10 ppm of impurity. Surface color, pore size, stabilized layer, and phase change are confirmed with optical microscopy, SEM-EDS, Micro-Raman, and X-ray diffraction (XRD) according to the Zr getter temperature. The surface color of the Zr getter changes from metallic silver to dark gray as temperature increases. In the EDS results, the nitrogen component is not observed, and oxygen content increases from each surface at elevated temperatures. The Raman and XRD results show the oxidation layer as a result of 350 oC annealing. Therefore, the Zr getter can be applied as a nitrogen getter under 5-nine purity nitrogen atmosphere after appropriate oxidized pre-stabilization process to prevent rapid nitrification reaction.

In order to accelerate the biodegradation of easily organic materials in landfilled waste before excavating a closed solid waste landfill and prevent to be dried the landfilled wastes at the same time, this study has suggested the Dual Step Biostabilization System (DSBS), which could inject air with dry fog into its body. In addition, the applicability of the DSBS was estimated by means of field test at a closed landfill. As a result of field test, the reduction of oxygen consumption rate for landfilled wastes (48%) stabilized by air with dry fog was higher than that of landfilled wastes (38%) stabilized by only air. Three lysimeter experiments were, also, performed for the landfilled wastes sampled from the closed landfill. The production of cumulative carbon dioxide for landfilled wastes stabilized by air with dry fog was estimated to be highest (1,144.8 mL). In case of lysimeter that moisture was not introduced was found to be 1,051.9 mL, while another lysimeter that moisture was introduced through horizental trenches was 1,095.8 mL. It is clear that the DSBS can accelerate the biodegradation of organic compounds. In terms of volatile solids, the reduction amount of volatile solids for air with dry fog was higher than that of the other conditions.

The objective of this research was to suggest the estimation method of air injection quantity for pre-stabilization of landfilled wastes in a sustainable landfill. A study on the determination of oxygen demand quantity of landfilled wastes, therefore, was conducted in two different experiments. Firstly, a batch test was performed in order to measure the oxygen quantity required to oxidize easily degradable organic matter under aerobic conditions. Secondly, a lysimeter experiment was carried out to assess the air injection period according to moisture content (20%, 30%, 40%, 50%) and to validate the oxygen demand quantity obtained by the batch test. This study assumed that landfilled wastes contain two different organic matters and two matters are sequentially utilized by microorganism. The first one provides the faster oxygen uptake rate that called the “easily degradable organics”. During the second phase of the aerobic decomposition, the other one provides the slower oxygen uptake rate that called the “moderately degradable organics”. Also, in this study, a modified logistic equation divided two terms (fractions of easily degradable organic and moderately degradable organic) was suggested to determine the oxygen demand quantity for easily degradable organic of landfilled solid waste. As a result, the oxygen demand quantity obtained by the batch test led to similar results compared with that of lysimeter experiment. Therefore, it showed that the modified logistic equation and batch test were appropriate for determination of oxygen demand quantity for decomposition of easily degradable organic matter. Also, air injection period for decomposition of easily degradable organic decreased with the increase of moisture content.