| Summary: | 碩士 === 國立中央大學 === 土木工程研究所 === 88 === Because Taiwan''s habitable land is scarce, finding a land for solid waste disposal is very difficult. For a period decades, river side have been used as disposal sites of solid waste, thus causing large amounts of solid waste resides in riverbeds and might adversely affect the environment. This research focuses on side the percolation water quality from disposal sites within the river side. To establish a predicting model for policy makers to determine whether dump sites should be relocated or simply stabilized on site. Lu Chou site is taken as a case study.
This research uses a water balance approach of a disposal site on a high-water-terrain in river side and a leachate quality model in combination with on-site data measurements, vertical electrical survey (VES), meteorologic data. For example the infiltration parameter is obtained using a single-ring infiltrometer. It is determined that the greatest percolation volume occurs when rainfall amount minus evaporation amount is at the highest, while it is raining and the soil is saturated with water. The months that a percolation value exceeding 60mm are February, June, August, and September. Another way to determine percolation volume is to view it as leachate volume. According to the calculated COD concentration, the amount of leachate exceeds 50,000kg of COD annually during the first four years after landfilling. In addition, through out the years, there were times when the contaminant concentration peaked. The concentration peaks when the leachate volume or percolation volume was the greatest, thus causing greater contamination volume. This research found that after the first four years of a landfill''s operation, the leachate amount or percolation amount gradually decreased. Therefore, when not considering river channel safety, river side landfill leachate amount in 1998 decreased to 3,221.4 kg/year of COD.
In conclusion, it is not cost-effective to relocate existing landfills that existed for 5 years or longer because such project would be labor-intensive and it might generate secondary contamination threat. Furthermore, if landfill site exists for more than five years, then any contamination may be remediated and controlled on site.
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