Electrical resistivity evaluation of MICP solidified lead contaminated soil

• Published in: Environmental earth sciences 2024-04, Vol.83 (8), p.261, Article 261
• Main Authors: Zha, Fusheng, Yang, Zhilong, Kang, Bo, Shen, Yinbin, Liu, Guiqiang, Tao, Wenbin, Chu, Chengfu
• Format: Article
• Language: English
• Subjects: Biogeosciences; Carbonates; Chemical precipitation; Correlation; Curing; Curing (processing); Earth and Environmental Science; Earth Sciences; Electrical resistivity; Empirical models; Environmental Science and Engineering; Geochemistry; Geology; Heavy metals; Hydrology/Water Resources; Immobilization; Lead; Metal concentrations; Microbial contamination; Moisture content; Original Article; Pollutants; Soil; Soil contamination; Soil improvement; Soil pollution; Soil remediation; Soil strength; Soil structure; Soils; Solidification; Terrestrial Pollution; Water content; Water pollution
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-024-11568-4

Microbially induced carbonate precipitation (MICP) stands as a potent technique for remediating soils contaminated with heavy metals. However, the lack of efficient methods to detect the efficacy of MICP necessitates the use of electrical resistivity as an indicator. Consequently, an empirical model was devised to assess the strength and lead curing rate of the remediated soil. Through resistivity tests and microscopic experiments, it became evident that water content and lead contamination concentration exerted an influence on the electrical resistivity of the soil. Remarkably, the MICP technology led to a significant increase in the electrical resistivity of the remediated soil. This phenomenon can be attributed to the immobilization of lead ions within the contaminated soil, which consequently alters the soil’s pore structure, thereby resulting in noticeable modifications in electrical resistivity. The empirical model further revealed a linear correlation between the strength of the remediated soil and its electrical resistivity. As the electrical resistivity increased from 1.09 to 8.71 Ω m, the strength of the soil improved from 175 to 1070 kPa. Additionally, a multifactor linear framework elucidated the interrelation between the lead curing rate and water content, primary lead contamination concentration, and electrical resistivity. The rate of lead solidification showed a positive correlation with water content but exhibited a negative correlation with both the initial concentration of heavy metal pollutants and the electrical resistivity. Notably, the highest rate of lead curing rate, reaching 90.89%, was observed at a water content of 16.1%, a pollutant concentration of 100 mg/kg, and an electrical resistivity of 1.54 Ω m. These findings firmly establish electrical resistivity as an effective means of evaluating the remediation effect of MICP, thereby providing a theoretical foundation for assessing the impact of MICP technology in the field.