Protocol for laboratory testing of crude-oil bioremediation products in freshwater conditions.

In 1993, the Environmental Protection Agency, National Risk Management Research Laboratory (EPA, NRMRL), with the National Environmental Technology Application Center (NETAC), developed a protocol for evaluation of bioremediation products in marine environments [18]. The marine protocol was adapted for application in freshwater environments by using a chemically defined medium and an oil-degrading consortium as a positive control. Four products were tested using the modified protocol: two with nutrients and an oleophilic component; one with nutrients, sorbent, and organisms; and one microbial stimulant. A separate experiment evaluated the use of HEPES and MOPSO buffers as replacements for phosphate buffer. The oleophilic nutrient products yielded oil degradation similar to the positive control, with an average alkane removal of 97.1+/-2.3% and an aromatic hydrocarbon removal of 64.8+/-1.2%. The positive control, which received inoculum plus nutrients, demonstrated alkane degradation of 98.9+/-0.1% and aromatic degradation of 52.9+/-0.1%. The sorbent-based product with inoculum failed to demonstrate oil degradation, while the microbial stimulant showed less oil degradation than the positive control. Replacement of phosphate buffer with other buffers had no significant effect on one product's performance. Differences in product performance were easily distinguishable using the protocol, and performance targets for alkane and aromatic hydrocarbon degradation are suggested.

Effectiveness of an anaerobic granular activated carbon fluidized-bed bioreactor to treat soil wash fluids: a proposed strategy for remediating PCP/PAH contaminated soils.

An integrated system has been developed to remediate soils contaminated with pentachlorophenol (PCP) and polycyclic aromatic hydrocarbons (PAHs). This system involves the coupling of two treatment technologies, soil-solvent washing and anaerobic biotreatment of the extract. Specifically, this study evaluated the effectiveness of a granular activated carbon (GAC) fluidized-bed reactor to treat a synthetic-waste stream of PCP and four PAHs (naphthalene, acenaphthene, pyrene, and benzo(b)fluoranthene) under anaerobic conditions. This waste stream was intended to simulate the wash fluids from a soil washing process treating soils from a wood-preserving site. The reactor achieved a removal efficiency of greater than 99.8% for PCP with conversion to its dechlorination intermediates averaging 46.5%. Effluent, carbon extraction, and isotherm data also indicate that naphthalene and acenaphthene were removed from the liquid phase with efficiencies of 86 and 93%, respectively. Effluent levels of pyrene and benzo(b)fluoranthene were extremely low due to the high-adsorptive capacity of GAC for these compounds. Experimental evidence does not suggest that the latter two compounds were biochemically transformed within the reactor.