Laboratory study of bioremediation of rocket fuel-polluted groundwater

Feasibility of bioremediation for detoxification of rocket fuel-polluted groundwater was studied in laboratory conditions. A relatively high number (4×106 CFU/ml) of indigenous rocket fuel-degrading bacteria in the polluted groundwater from the abandoned Keila-Joa missile base was found, but bacterial growth in batch experiments using groundwater was strongly inhibited by the high concentration of pollutants. This inhibition was alleviated after at least two-fold dilution by pure water. The efficiency of solar photooxidation as a pre-treatment option for bioremediation was studied. Partial photooxidation of the polluted groundwater (yielding a decrease of the concentration of primary aromatic amines by 20%) increased the biodegradability, but also the toxicity of the groundwater nearly three times. In the course of two weeks of aerobic incubation the primary aromatic amines could be degraded to the residual concentration of 6–10 mg/l. The removal of primary aromatic amines was not accompanied by simultaneous reduction of toxicity, which started to decrease only after amine concentration decreased to its lowest level of 6–10 mg/l.