In order to clarify the landfilled waste in 16 land serial numbers such as 568, Jia'an Section, Houbi District, Tainan City, this project uses geophysical exploration combined with geological drilling, excavation and other survey methods to define the scope, depth and type of waste. To estimate the amount of waste buried and subsequent cost for cleanup, and to investigate the quality of soil and groundwater, to assess the impact of waste on the surrounding environment.
The survey results show that the depth of landfilled waste at the site varies greatly. It is presumed to be landfilled after excavation, and land preparation is not from the original agricultural land surface. It is irregular excavation methods and the overall landfilled depth is less than 5 meters. The landfilled area is 51,118 square meters, accounting for about 85% of the site area. No waste was found on the southeast side of the site. The waste burial area is similar to the unvegetated area in the aerial photograph of May 6, 1998. The amount of waste is estimated about 60,872 cubic meters and 124,788 tons. The detection results of heavy metals in the original soil and the surrounding groundwater are in compliance with the regulatory pollution monitoring standards.
According to the chemical composition of the waste, it is judged that the waste at the site is stainless steel slag. No other industrial waste was found. From the particle size composition, it is estimated that the oxidizing slag is mainly concentrated in the central area of the site, and most of the other areas are mainly reducing slag or a mixture of oxidizing slag and reducing slag. From relevant evidence, it is inferred that the source of the slag at this site is Walsin Lihwa Co., Ltd. Yenshui Plant, and the reuse organization is the Yenshui Plant of Xiangshan Furnace Resources Enterprise Co., Ltd. The slag should be crushed and screened before landfilling.
Based on the historical documents, the aerial photographs over the years, and the survey results of this project, it is speculated that Chaoxiang Company began to stack the slag on the site between January and May 2008. The excavation and landfilling of the slag was carried out between October 2008 and May 2009, and the soil covering was finally completed between May and July 2009. This behavior violates the relevant regulations of the electric arc furnace steelmaking ballast reuse management method, the waste disposal law and the regional planning law. Chaoxiang Company shall be responsible for the follow-up slag cleaning of the site.
If the obligor of clean-up does not clean up and dispose of waste in accordance with regulations, the competent authority may clean up on its behalf. The estimated time of the site's slag cleaning project is 2 years, and the on-site cleaning project cost is 138,188,380 NTD. With three off-site slag disposal solutions, the total cost is estimated to be between 932,306,262 and 3,906,469,539 NTD. It is recommended to give priority to the treatment of slag by recycling, which is the most cost-effective and in line with the Environmental Protection Agency's circular economy policy. Landfill disposal is the most expensive, and it is the last option.
