Science Inventory

Enhanced degradation of polycyclic aromatic hydrocarbons by indigenous microbes combined with chemical oxidation

Citation:

Liao, X., Z. Wu, Y. Li, J. Luo, AND C. Su. Enhanced degradation of polycyclic aromatic hydrocarbons by indigenous microbes combined with chemical oxidation. CHEMOSPHERE. Elsevier Science Ltd, New York, NY, 213:551-558, (2018). https://doi.org/10.1016/j.chemosphere.2018.09.092

Impact/Purpose:

Polycyclic aromatic hydrocarbons (PAHs) are widespread pollutants, commonly found at sites associated with coking, petroleum production industries and incomplete combustion of wood. Although some innovative methods were used to remediate contaminated soils, an increasing focus is placed on less adverse environmentally influencing and more cost-effective in situ remediation technologies, such as in-situ chemical oxidation (ISCO) and in-situ microbiological degradation. In this study, the removal efficiency PAHs by chemical oxidation combined with microbe remediation was evaluated in two contaminated soils. The number of indigenous soil microbes decreased after the addition of chemical oxidants and then increased by nutrients addition. The total removal efficiencies of PAHs by chemical oxidation and nutrient addition followed the order: activated persulfate > potassium permanganate > modified Fenton reagent > Fenton reagent. There are 24.3-28.0%, 22.0-23.7%, 10.3-13.7% and 1.9-2.5% contributions separately due to nutrient treatment in Fenton, modified Fenton, activated persulfate and potassium permanganate treatment. The different chemical oxidants exhibited 78-90% removal efficiency for 5-6 rings PAHs, while 52.0-85.0% removal efficiency for 2-4 rings PAHs. With the addition of nutrients, the growth of indigenous microbes was enhanced significantly, and the contents of 2-4 rings PAHs in the soil were further decreased. Furthermore, the removal efficiencies of NAP and ANY were increased by more than 45.0%, while the removal efficiencies of ANE, FLE and PHE were about 30.0% at Fenton system. There was a complementary enhancing effect of chemical oxidation and microbial remediation for PAHs degradation. The results can be used by EPA program offices (OLEM), Regions, States, and industry for evaluation of different technologies for site remediation.

Description:

In this study, the removal efficiency PAHs by chemical oxidation combined with microbe remediation was evaluated in two contaminated soils. The number of indigenous soil microbes decreased after the addition of chemical oxidants and then increased by nutrients addition. The total removal efficiencies of PAHs by chemical oxidation and nutrient addition followed the order: activated persulfate > potassium permanganate > modified Fenton reagent > Fenton reagent. There are 24.3-28.0%, 22.0-23.7%, 10.3-13.7% and 1.9-2.5% contributions separately due to nutrient treatment in Fenton, modified Fenton, activated persulfate and potassium permanganate treatment. The different chemical oxidants exhibited 78-90% removal efficiency for 5-6 rings PAHs, while 52.0-85.0% removal efficiency for 2-4 rings PAHs. With the addition of nutrients, the growth of indigenous microbes was enhanced significantly, and the contents of 2-4 rings PAHs in the soil were further decreased. Furthermore, the removal efficiencies of NAP and ANY were increased by more than 45.0%, while the removal efficiencies of ANE, FLE and PHE were about 30.0% at Fenton system. There was a complementary enhancing effect of chemical oxidation and microbial remediation for PAHs degradation.