(477a) Remediation of Diesel-Contaminated Soil With a Biostimulation and Bioaugmentation Joint Process

Remediation of diesel-contaminated soil with a biostimulation and bioaugmentation joint process

Xiaosen Li, Diannan Lu and Zheng Liu*

Department of Chemical Engineering, Tsinghua University, Beijing 100084, China

lixs09@mails.tsinghua.edu.cnludiannan@mail.tsinghua.edu.cn

*Corresponding author: Phone: 86-10-6277-9876

Email: liuzheng@mail.tsinghua.edu.cn

A new remediation process that integrates biostimulation and bioaugmentation was proposed for diesel-contaminated soil. In addition to the determination of the residue diesel in soil, the total dehydrogenase activity, the microbial community changes in terms of composition and quantity of both microbial community and functional genes were probed by molecular biological techniques. In this research, five bacterial strains capable of degrading diesel were isolated from contaminated sites, in which Rem-E gave the highest degradation efficiency compared to the others and thus used as the additive strain for the bioaugmentation. As for biostimulation, monopotassium phosphate and ammonium sulfate were added to achieve an optimal C:N:P being determined as 100:1.25:1. After 10 day biosimulation, the content of diesel reduced from 2.7% to 1.6%. The joint process by biostimulation and bioaugmentation, however, gave a reduction of disel content from 2.7% to 0.6% in 40 days. Pyrosequencing for the total DNA extracted from the soil showed the evolution of the microbial community and qPCR revealed the change of the functional genes during the remediation process. The result revealed that coupling degrading strain and source of phosphorus and nitrogen led to the highest dehydrogenase activity and degradation rate, which also recover almost all the microbial community in the soil after the remediation. This work showed the great potential of the coupling technology composed of bioaugmentation and biostimulation for the remediation of the oil-contaminated soil. It also offers a viable route for the application of molecular biological techniques as enabling tools in the monitor, design, implementation and assessment of bioremediation practice.