사용종료매립지 선별토사의 특성분석을 통한 안정성 평가

Abstract

This study was conducted as a preliminary research to evaluate the reusability of the screened soil from a closed landfill. For this purpose, we determined the physico-chemical properties of five soil samples collected from a closed landfill site with dumped ages of 1, 5, 10, 15, and 20 years. Gas evolution and leachate analysis were also performed using lab-scale lysimeters. According to sieve analyses, all screened soil samples were within the range of well-graded standard. However, hand-separation showed that rates of non-soil content by volume in all screened soils were higher than the regulation, i.e. 1% by volume except 20 year-old soil. There was no trend in volatile solid (VS) of screened soil along the dumped age. However, microbial activity test showed the identical results to soil respiration test and can be a good indicator for the stabilization of closed landfills. Humic substances extraction test also showed that the portion of non-humic substances in soil organic matter (SOM) decreased with the increase of dumped age. Results obtained from tests demonstrated that decomposition of wastes was still ongoing and the soil samples were not stabilized even after 20 years of dumped age. Therefore, screened soil from waste dumping site should be appropriately remediated to stabilize wastes-origin, biodegradable organic fractions before reuse.