Nitrate Enhanced Bioremediation Restores Fuel Contaminated Groundwater to Drinking Water Standard

Nitrate enhanced bioremediation solubility of oxygen. Nitrate is more soluble than oxygen and is less expensive. The significance of the nitrate bioremediation at Traverse City is that the concentration of nitrate used in the bioremediation was below Federal drinking water standards. that when nitrate and nutrients were added, they could be evenly distributed In order to determine the effects of dilution of the contaminants in the recirculated groundwater and the effects of natural bioremediation, nitrate and nutrients were not added for six weeks. Prior to the addition of the nitrate, the area was sampled to evaluate what biorestoration had occurred without nitrate enhancement. This analysis found that indigenous ambient concentrations of oxygen and nitrate had removed benzene to below 0.1 μg/L, from initial concentrations of 760 μg/L. The other contaminants required artificially induced nitrate additions to achieve acceptable levels. restored a jet fuel contaminated aquifer to drinking water standard levels within 165 days. This field demonstration, at the U.S. Coast Guard Facility at Traverse City, MI, repeated and validated a remediation conducted in the Upper Rhine Valley in Germany more than ten years ago. To the author’s knowledge, nitrate enhanced bioremediation has been used at only one other fuel contaminated site in the United States, One factor constraining the use of nitrate bioremediation is that nitrate in groundwater is subject to a drinking water standard. Yet, nitrate presents a viable treatment alternative to, oxygen enhanced bioremediation. Although oxygen has been effective for many fuel spills, success is sometimes limited due to the low At Traverse City, jet fuel containing benzene, toluene, ethylbenzene and xylene compounds had leaked from underground storage facilities. The fuel contaminated both the unsaturated soils and the aquifer. For this reason, it was necessary to install an infiltration gallery system as the first stage of bioremediation prior to the addition of the nitrate. The infiltration gallery system, using pumped aquifer groundwater, saturated the unsaturated zone so Jet fuel