Emulsified polycolloid substrate biobarrier for benzene and petroleum-hydrocarbon plume containment and migration control - A field-scale study

T H Lee; W Z Cao; D C W Tsang; Y T Sheu; K F Shia; C M Kao

doi:10.1016/j.scitotenv.2019.02.160

Emulsified polycolloid substrate biobarrier for benzene and petroleum-hydrocarbon plume containment and migration control - A field-scale study

Sci Total Environ. 2019 May 20:666:839-848. doi: 10.1016/j.scitotenv.2019.02.160. Epub 2019 Feb 12.

Authors

T H Lee¹, W Z Cao², D C W Tsang³, Y T Sheu¹, K F Shia¹, C M Kao⁴

Affiliations

¹ Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
² College of the Environment and Ecology, Xiamen University, Xiamen, China.
³ Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
⁴ Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan. Electronic address: jkao@mail.nsysu.edu.tw.

PMID: 30818208
DOI: 10.1016/j.scitotenv.2019.02.160

Abstract

The objective of this field-scale study was to assess the effectiveness of applying an emulsified polycolloid substrate (EPS; containing cane molasses, soybean oil, and surfactants) biobarrier in the control and remediation of a petroleum-hydrocarbon plume in natural waters. An abandoned petrochemical manufacturing facility site was contaminated by benzene and other petroleum products due to a leakage from a storage tank. Because benzene is a petroleum hydrocarbon with a high migration ability, it was used as the target compound in the field-scale study. Batch partition and sorption experiment results indicated that the EPS to water partition coefficient for benzene was 232 mg/mg at 25 °C. This suggests that benzene had a higher sorption affinity to EPS, which decreased the benzene concentrations in groundwater. The EPS solution was pressure-injected into three remediation wells (RWs; 150 L EPS in 800 L groundwater). Groundwater samples were collected from an upgradient background well, two downgradient monitor wells (MWs), and the three RWs for analyses. EPS injection increased total organic carbon (TOC) concentrations (up to 786 mg/L) in groundwater, which also resulted in the formation of anaerobic conditions. An abrupt drop in benzene concentration (from 6.9 to below 0.04 mg/L) was observed after EPS supplementation in the RWs due to both sorption and biodegradation mechanisms. Results show that the EPS supplement increased total viable bacteria and enhanced bioremediation efficiency, which accounted for the observed decrease in benzene concentration. The first-order decay rate in RW1 increased from 0.003 to 0.023 d^-1 after EPS application. Injection of EPS resulted in significant growth of indigenous bacteria, and 23 petroleum-hydrocarbon-degrading bacterial species were detected, which enhanced the in situ benzene biodegradation efficiency. Results demonstrate that the EPS biobarrier can effectively contain a petroleum-hydrocarbon plume and prevent its migration to downgradient areas, which reduces the immediate risk presented to downgradient receptors.

Keywords: Biobarrier; Emulsified polycolloid substrate (EPS); Green remediation; In situ bioremediation; Partition; Petroleum hydrocarbon.

MeSH terms

Bacteria / classification*
Biodegradation, Environmental
Colloids / analysis*
Denaturing Gradient Gel Electrophoresis
Emulsions / analysis
Groundwater / chemistry
Hydrocarbons / analysis*
Microbiota*
Petroleum Pollution / prevention & control*
Water Pollutants, Chemical / analysis*
Water Pollution, Chemical / prevention & control*

Substances

Colloids
Emulsions
Hydrocarbons
Water Pollutants, Chemical