Surfactant-enhanced bioremediation of DDTs and PAHs in contaminated farmland soil

ABSTRACT

Field-scale bioremediation of dichlorodiphenyl trichloroethanes (DDTs) and polycyclic aromatic hydrocarbons (PAHs) contaminated farmland soil from the Shenyang North New Area of China was studied using the bacteria Arthrobacter globiformis. The additive effects of different concentrations of biosurfactant rhamnolipids (RLs) and anionic–nonionic mixed surfactant (SDBS–Tween 80) were evaluated. DDT and PAH removal rates by A. globiformis after 150 days of remediation were 52.1% and 21.9%, respectively. At the optimum RL concentration of 5 mg kg⁻¹, DDTs and PAHs had removal rates of 64.3% and 35.6%, respectively, at 150 days. This was 60.7% and 29.3% higher than the control; 36.9% and 19.8% higher than soil with RL-5 alone; and 12.2% and 13.8% higher than the A. globiformis treatment alone. RL-5 can enhance soil enzyme activity and A. globiformis reproduction during the DDT and PAH biodegradation processes. This study illustrates a highly efficient, low-cost in situ soil bioremediation technology that could have practical utility.

KEYWORDS:

• DDTs
• PAHs
• A. globiformis
• surfactants
• RL
• SDBS–Tween 80
• farmland soil

Acknowledgements

The authors thank the staff of Shenyang University Laboratory of Eco-Remediation and Resource Reuse for their support during field sampling, logistics, and laboratory analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was financially supported by the National Basic Research Program of China (973 Program) [2014CB441106], Major Science and Technology Program for Shenyang Science and Technology Plan Project [F14-133-9-00], Science and Enterprise Competitive Selection Project of Shenyang City (Study on Risk Management and Remediation Technology of Urban Ecological Environment), and ‘123 Project’ of China Environment Protection Foundation [CEPF2013-123-1-7].