TY - JOUR
T1 - Effect of acidity on attenuation performance of sandy soil amended with granular calcium-magnesium composite
AU - Gathuka, Lincoln W.
AU - Kato, Tomohiro
AU - Takai, Atsushi
AU - Flores, Giancarlo
AU - Inui, Toru
AU - Katsumi, Takeshi
N1 - Publisher Copyright:
© 2021
PY - 2021/8
Y1 - 2021/8
N2 - Utilising naturally contaminated soils and rocks is essential for significantly reducing geo-waste. However, there are no well-established concepts regarding the methods or countermeasures for utilising these soils and rocks, which would realise cost-effectiveness and environmental safety. Therefore, several researches focusing on the attenuation layer method have recently been undertaken. This method involves installing an attenuation layer between the contaminated materials and the ground to prevent ground contamination due to the attenuation capacity. A critical issue in the attenuation layer's design is to evaluate the attenuation performance of the layer material against target chemicals. Several important concerns and questions need to be solved when evaluating the attenuation performance. One is how the acidic leachate might diminish the layer material's attenuation performance. This paper presents the attenuation performance of a soil amended with a granular calcium-magnesium composite against acidic leachate. Batch and column tests, employing arsenic solutions of pH 2, 4 and 6, were applied to evaluate its attenuation performance. Using Freundlich parameter K as an index, the soil's attenuation performance was determined to have improved by at least 40% after the addition of the agent, even when the agent content was 5%. The amended soil's attenuation performance should be similar if the leachate pH is pH 6–4, although it might reduce by up to ~30% for pH < 4. Moreover, the amended soil can buffer the acid to pH > 6. If the attenuation layer buffers the acid and provides the leachate with pH > 6, it will assure that the original ground's attenuation capacity is utilised. Considering this work's findings, amended soil can be employed as material for the attenuation layer.
AB - Utilising naturally contaminated soils and rocks is essential for significantly reducing geo-waste. However, there are no well-established concepts regarding the methods or countermeasures for utilising these soils and rocks, which would realise cost-effectiveness and environmental safety. Therefore, several researches focusing on the attenuation layer method have recently been undertaken. This method involves installing an attenuation layer between the contaminated materials and the ground to prevent ground contamination due to the attenuation capacity. A critical issue in the attenuation layer's design is to evaluate the attenuation performance of the layer material against target chemicals. Several important concerns and questions need to be solved when evaluating the attenuation performance. One is how the acidic leachate might diminish the layer material's attenuation performance. This paper presents the attenuation performance of a soil amended with a granular calcium-magnesium composite against acidic leachate. Batch and column tests, employing arsenic solutions of pH 2, 4 and 6, were applied to evaluate its attenuation performance. Using Freundlich parameter K as an index, the soil's attenuation performance was determined to have improved by at least 40% after the addition of the agent, even when the agent content was 5%. The amended soil's attenuation performance should be similar if the leachate pH is pH 6–4, although it might reduce by up to ~30% for pH < 4. Moreover, the amended soil can buffer the acid to pH > 6. If the attenuation layer buffers the acid and provides the leachate with pH > 6, it will assure that the original ground's attenuation capacity is utilised. Considering this work's findings, amended soil can be employed as material for the attenuation layer.
KW - Arsenic
KW - Attenuation layer
KW - Naturally contaminated soils
KW - pH buffering
UR - http://www.scopus.com/inward/record.url?scp=85107912025&partnerID=8YFLogxK
U2 - 10.1016/j.sandf.2021.05.007
DO - 10.1016/j.sandf.2021.05.007
M3 - Article
AN - SCOPUS:85107912025
SN - 0038-0806
VL - 61
SP - 1099
EP - 1111
JO - Soils and Foundations
JF - Soils and Foundations
IS - 4
ER -