| Title: | Air sparging remediation of VOCs contaminated low-permeability soil based on pressure gradient control |
| Author(s): | Xu L; Zhu H; Zha F; Kang H; Fang L; Liu J; Tan X; Chu C; |
| Address: | "School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China. School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China. Electronic address: geozha@hfut.edu.cn. Tianjin Bochuan Geotechnical Engineering Co., Ltd., Tianjin, 300350, China. School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China; Anhui Urban Construction Design Institute Corp., Ltd., Hefei, 230051, China" |
| DOI: | 10.1016/j.chemosphere.2023.139650 |
| ISSN/ISBN: | 1879-1298 (Electronic) 0045-6535 (Linking) |
| Abstract: | "Air sparging (AS) is deemed unacceptable for remediating VOCs contaminated soil with low-permeability. To improve air flow and contaminant removal in sparging process, an original approach, termed as pressure gradient-enhanced air sparging (PGEAS) approach, is proposed by controlling pressure gradient in soil. Then the remediation efficiency, mass transfer characteristics, and remediation mechanism are investigated. Results showed that, the PGEAS approach accelerates gaseous contaminant exhaust, reduces residue contamination in soil, and promotes total contaminant removal, finally results in an improved remediation efficiency compared to the conventional approach. Controlled by sparging pressure and flow distance, the pressure gradient is created in soil, and a critical value needs to be exceeded to enhance the VOCs removal and mass transfer characteristics. The measured results of pore pressure and liquid saturation confirm a notable pressure gradient and drainage behavior in soil, which indicate the massive air subchannel formation during air sparging. At a two-dimensional scale, discrete distributions of contaminant concentrations in exhaust air and soil are presented, the removal extent and area are both enhanced using the PGEAS approach with a pressure gradient higher than the critical value. The reached conclusions are of great importance to contaminant removal in heterogeneous stratigraphy at sites" |
| Keywords: | Soil/chemistry Air Gases Chemical Phenomena Permeability *Soil Pollutants/analysis *Environmental Restoration and Remediation Air sparging Low-permeability soil Pressure gradient Remediation efficiency Volatile organic compounds; |
| Notes: | "MedlineXu, Long Zhu, Huimin Zha, Fusheng Kang, Heyong Fang, Lixing Liu, Jingjing Tan, Xiaohui Chu, Chengfu eng England 2023/07/27 Chemosphere. 2023 Oct; 339:139650. doi: 10.1016/j.chemosphere.2023.139650. Epub 2023 Jul 24" |
