Comparison of Chemical and Biological Strategies for the Cleanup of Diesel/Biodiesel Blend–Contaminated Groundwater

The widespread use of diesel/biodiesel blends as a transportation fuel can increase the risk of groundwater contamination, which requires remediation actions. Two pilot-field experiments were conducted to assess and compare their potential to treat groundwater contaminated with B20 (20% biodiesel and 80% diesel, v/v), using combined iron and sulfate biostimulation (CISB) and a modified Fenton system (MFS). A low-cost and sustainable product recovered from acid mine drainage was used to stimulate both iron- and sulfate-reducing conditions. The modified Fenton system was composed of magnesium peroxide to promote the slow release of hydrogen peroxide by magnesium peroxide decomposition. Fe 2 O 3 recovered from acid mine drainage was used as catalyst for modified Fenton reaction. Both technologies demonstrated to efficiently degrade B20-blend aromatic hydrocarbons. However, the application of MFS maintained BTEX dissolved concentrations below the detection limit (1 μg L −1 ) over 22 months, while in CISB, the dissolved concentrations of BTEX compounds were > 50 μg L −1 after 8.4 months. Additionally, total PAH dissolved concentrations in MFS experiment were lower than those observed for the CISB plot. In MFS, microbial growth was inhibited as opposed to CISB in which microbial growth enhanced up to 3 orders of magnitude. Therefore, though MFS was more efficient to meet remediation goals relative to CISB approach, if the site requires complete restoration, less aggressive technologies such as CISB should be considered. This novel pilot study presents chemical and biological technologies that can potentially be applied to remediate diesel/biodiesel blends in groundwater.