Polycyclic aromatic hydrocarbons and polychlorobiphenyls in wastewaters and sewage sludges from the Paris area (France).

A two-phase partitioning bioreactor (TPPB) utilizing the bacterium Sphingomonas aromaticivorans B0695 was used to degrade four low molecular weight (LMW) polycyclic aromatic hydrocarbons (PAHs). The TPPB concept is based on the use of a biocompatible, immiscible organic solvent in which high concentrations of recalcitrant substrates are dissolved. These substances partition into the cell-containing aqueous phase at rates determined by the metabolic activity of the cells. Experiments showed that the selected solvent, dodecane, could be successfully used in both solvent extraction experiments (to remove PAHs from soil) and in a TPPB application. Further testing demonstrated that solvent extraction from spiked soil was enhanced when a solvent combination (dodecane and ethanol) was used, and it was shown that the co-solvent did not significantly affect TPPB performance. The TPPB achieved complete biodegradation of naphthalene, phenanthrene, acenaphthene and anthracene at a volumetric consumption rate of 90 mg l–1 h–1 in approximately 30 h. Additionally, a total of 20.0 g of LMW PAHs (naphthalene and phenanthrene) were biodegraded at an overall volumetric rate of 98 mg l–1 h–1 in less than 75 h. Degradation rates achieved using the TPPB and S. aromaticivorans B0695 are much greater than any others previously reported for an ex situ PAH biodegradation system operating with a single species.

/pdf/use-of-a-two-phase-partitioning-bioreactor-for-degrading-3f4b997i46.pdf

Use of a two-phase partitioning bioreactor for degrading polycyclic aromatic hydrocarbons by a Sphingomonas sp.

Important in this study was the landfarm on Kreekraksluizen where landfarming was investigated in cooperation with RIZA, during a period of more than 10 years, which made it possible to predict the effect of landfarming in the long term. The database for this site is unique and will be extended in the future. The large experimental research on Kreekraksluizen was supported by several studies at other sites and in the laboratories of Alterra. As a traditional management practice, slightly polluted sediments from ditches in the rural area of The Netherlands are spread over adjacent land. In experiments on the island of Goeree-Overflakkee, it has been shown that the practice of spreading of thin layers also led to fast, slow and very slow degradation of the PAH's present

/pdf/landfarming-of-polycyclic-aromatic-hydrocarbons-and-mineral-3e26rxbk99.pdf

Landfarming of polycyclic aromatic hydrocarbons and mineral oil contaminated sediments

On line biomonitors used as a tool for toxicity reduction evaluation of in situ groundwater remediation techniques

Analytical techniques applicable to the assay and remediation of cutting/mud matrices have been developed, utilising soxhlet extraction with dichloromethane and a drying agent followed by analysis using Gas Chromatography (FID). Calibration curves of oil content were produced for Novatec and Versaplus coated cuttings that were also sized by wet and dry sieving techniques, demonstrating their variable nature. The oil in each size fraction was assessed and showed that the finer fractions preferentially adsorbed the oil. Bacteria were isolated from the cuttings, muds and the pure oils to see if any indigenous species could, with optimum conditions, remediate the oil they contained. The resulting isolates were batch-tested in the laboratory in a minimal medium, with the drill cuttings providing the sole carbon source. Each isolate was scored for remediation performance, with reduction in oil varying from 50% to 6% within one week. Subsequently three bacteria (A,D & J) were identified using 16SrRNA sequencing; they were Bacillus Thuringiensls (A&D) and a novel species related to Bacillus oleronius. These were then tested slurry-phase in a rotating drum bioreactor designed and fabricated for the research against a known remediator, Rhodococcus 9737, and a non-inoculated control for four weeks. All the reactors remediated, but Rhodococcus 9737 reduced the oil to 35% of the original, A, D and other isolates as a consortium to 83% and J, 90%. Further tests in the bioreactors, after a modification to improve the air supply gave reductions of around 50% after four weeks. The high clay content of the cuttings was detrimental to significant levels of bioremediation in a slurry-phase bioreactor. Manures were added to the drill cuttings and tested in the bioreactors as a solid-phase system. These degraded the cuttings oil to 2% (v/v), a 96% reduction. Composting was thus more applicable for a high clay content drilling waste bioremediation system.

Guus C. Stefess

Papers

Monitoring of environmental effects and process performance during biological treatment of sediment from the petroleum Harbour in Amsterdam