Incineration bottom slag dechlorination and environmental impact assessment of seepage water from rainwater leaching

• Main Authors: Yu-Siang Cheng, 鄭宇翔
• Other Authors: Chih-Ming Kao
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/prfh8y

碩士 === 國立中山大學 === 環境工程研究所 === 107 === According to the statistics of the Environmental Protection Agency, there are 24 waste incinerators in Taiwan, and about 6.4 million wastes are processed into incineration plants every year. The amount of bottom slag produced each year is as high as 900,000 metric tons. In order to deal with this large amount of waste, the waste incineration plant Reuse of bottom slag is one of the current trends However, if the bottom slag is to be reused, it is necessary to overcome the two major difficulties that is, the bottom slag reuse must be stabilized by the aging process, and the second problem is that the chlorine content of most bottom slags is too high. The incineration bottom slag recycling plants in Taiwan use natural ripening process which requires two to three months, where the transfer of highly alkaline materials and heavy metals are deliberated. This study simulates the rainfall to find out the effluent water after the rainwater passes through the bottom slag. Although the pH value decreases with time, it still shows a high alkaline state of pH 10-11. Most of the heavy metal migration rate is also concentrated in 50-80%. The main leaching heavy metal is copper. The simulated heavy metal release can be used to predict the environmental impact of the bottom slag ripening site. According to the regulations of the Environmental Protection Agency of the Executive Yuan, the water-soluble chloride ion content of the first type of recycled pellets must be less than 0.024%, therefore, the bottom slag needs further treatment before it can be used. The results showed that most of the economic cost can be achieved when the solid-liquid ratio is 1:2, the oscillating time is 1 hour, and the amplitude utilization rate is 40%. The removal rate is 61.2%, and the chloride ion concentration in the bottom slag reduced to 0.021% in the fourth batch after continuous oscillating water washing. The regulatory standards can be used as the regenerative ingredient in the first type of recycling type products to make the garbage recycling resources.