Strategy using bioreactors and specially selected microorganisms for bioremediation of groundwater contaminated with creosote and pentachlorophenol

Abstract

A two-stage, sequential inoculation bioreactor strategy for the bioremediation of groundwater contaminated with creosote and pentachlorophenol (PCP) was evaluated at bench scale (1.2 L) and pilot scale (454 L). Bioreactor performance using specially selected microorganisms was assessed according to chemical analyses of system influent, effluent, and bioreactor residues, a chemical mass balance evaluation, and comparative biological toxicity and teratogenicity measurements. During pilot-scale operations, the concentration of creosote constituents was reduced from ca. 1000 ppm in the groundwater feed (flow rate 114 L/day) to <9 ppm in the system effluent (total removal efficiency of >99%). Notably, the cumulative concentration of carcinogenic polycyclic aromatic hydrocarbons was reduced from 368 ppm in the feed to 5.2 ppm in the system effluent. Moreover, the toxicity and teratogenicity of the bioreactor effluent were significantly reduced. In general, field data correlated well with those obtained from bench-scale studies.f Research contribution no. 822 of the Gulf Breeze Environmental Research Laboratory.

Cometabolic Degradation of Dibenzofuran and Dibenzothiophene by a Newly Isolated Carbazole-Degrading Sphingomonas sp. Strain

“…Moreover, because some of these heterocyclic compounds are mutagenic and carcinogenic (11,25), ecosystems contaminated with these compounds may elicit serious health risks (26). Fundamental research examining the biodegradation of these recalcitrant compounds and the application of bacteria in bioremediation for reducing their concentrations in the environment has been conducted (22).…”

Rapid Development of Microbial Strains for Bioremediation of Military Soils and Dredged Materials Contaminated with Polycyclic Aromatic Hydrocarbons.

“…Several treatment strategies have been tried with soils contaminated with PAHs alone or in combination with other hydrocarbons. These strategies include confined reactor treatment of slurries produced with the residues remaining after soil washing of creosote-contaminated soils (Mueller et al 1991a) and use of staged bioreactors and selected microorganisms for treatment of creosote-contaminated groundwater (Mueller et al 1993). Stroo (1992) has summarized the types of treatments obtained by providing native microorganisms with the environmental conditions necessary to stimulate activity within the soil matrix.…”

“…The ability to improve PAH removal by use of both native and specialty strains has been demonstrated (Mueller et al 1992(Mueller et al , 1993. Much of the research conducted at the Waterways Experiment Station (WES) has been directed to cleanup of soils contaminated with PAHs.…”

Recent developments in cleanup technologies

“…In actuality, however, one is quite challenged to find a single report in the peerreviewed scientific literature that unequivocally documents the successful use of inoculants in the field using conventional solid-phase or in situ bioremediation technologies on a practical scale. Alternatively, the most successful use of inoculants, beyond the laboratory or benchscale levels, has been in bioreactor operations (Mueller et al, 1991b;Mueller et al, 1993b;Mueller ec al., 1992).…”