Research Institute for Agriculture & Life Sciences, Seoul National University, Seoul, South Korea.
Research Institute for Agriculture & Life Sciences, Seoul National University, Seoul, South Korea; Department of Rural Systems Engineering, Seoul National University, Seoul, South Korea.
J Environ Manage. 2015 Jun 1;156:244-51. doi: 10.1016/j.jenvman.2015.03.033. Epub 2015 Apr 10.
Bottom ash and dredged soils can be used as construction materials because they are similar in physical characteristics to natural aggregates. However, whenever such byproducts as bottom ash and dredged soils are used, the energy efficiency of recycling is offset to a certain degree by emissions from transportation. The objective of this study is to analyze the environmental efficiency of recycling bottom ash and dredged soils through the estimation of CO2 emissions, considering both transportation distance and the mixing ratio. Agricultural reservoirs were selected as the final destinations of these recycled materials. This analysis demonstrated that using 100% bottom ash emits less CO2 than using natural aggregates when the ash is transported less than 35.15 km. This breakeven distance increases exponentially with the mass fraction of admixed dredged soil. However, admixture with natural soils does not affect the breakeven distance. Using the breakeven distances, the effective area with which it is efficient to recycle bottom ash was delineated. When dredged soil is admixed to a mass fraction of 70%, the effective area covers most of South Korea. In addition, 100% bottom ash was efficient in 1622 reservoirs (9.45%) in terms of CO2 emissions, and the mixture with 30% bottom ash and 70% dredged soils is efficient in 98.83% of all of the reservoirs in Korea. Bottom ash is most useful for reducing CO2 emissions when it is mixed with dredged soils, which are a byproduct of construction found on-site. This result is meaningful because bottom ash and dredged soils are complementary in their physical characteristics, and they need to be mixed before use as construction materials. The recycling of bottom ash becomes even more attractive with anticipated improvements in fuel efficiency.
底灰和疏浚土壤可用作建筑材料，因为它们在物理特性上与天然骨料相似。然而，只要使用底灰和疏浚土壤等副产品，运输过程中的排放就会在一定程度上抵消回收的能源效率。本研究的目的是通过估算 CO2 排放来分析回收底灰和疏浚土壤的环境效率，同时考虑运输距离和混合比。农业水库被选为这些回收材料的最终目的地。分析表明，当底灰的运输距离小于 35.15 公里时，使用 100%底灰比使用天然骨料排放的 CO2 更少。随着混合的疏浚土壤质量分数的增加，这个平衡距离呈指数增长。然而，与天然土壤混合并不影响平衡距离。使用平衡距离，描绘了回收底灰有效的区域。当混合的疏浚土壤达到 70%的质量分数时，有效区域覆盖了韩国的大部分地区。此外，就 CO2 排放而言，在 1622 个水库（9.45%）中，100%底灰是有效的，而 30%底灰和 70%疏浚土壤的混合物在韩国所有水库中有效率为 98.83%。当底灰与就地发现的建筑副产品疏浚土壤混合时，最有利于减少 CO2 排放。由于底灰和疏浚土壤在物理特性上具有互补性，需要在用作建筑材料之前混合，因此这一结果具有重要意义。随着燃料效率的提高，底灰的回收变得更具吸引力。
