Combined Anaerobic/Aerobic Biostimulation for Remediation of Rail Yards Contaminated by Diesel Engine Repair and Maintenance

Abstract

Perchloroethylene (PCE) and trichloroethylene (TCE) have been commonly used in the repair and maintenance of diesel engine locomotives. Improper handling, storage, and disposal lead to contamination of rail yard soils and groundwater with chlorinated ethylenes. Benzene, toluene, ethyl-benzene, and xylene (BTEX) are also common contaminants at rail yards because of the leakage of diesel fuel storage tanks and spills of diesel fuel. Co-contamination of groundwater with BTEX and chlorinated ethylenes allows for the application of anaerobic/aerobic bioremediation to achieve mineralization of both types of compounds. Bench scale laboratory experiments were run to select and enrich for an undefined, mixed, microbial consortium able to mediate PCE dechlorination to dichloroethylene (DCE), mineralization of the DCE, and mineralization of aromatic compounds. A periodically operated suspended culture reactor created alternating anaerobic/aerobic environments. When glucose was added to the reactor as the sole electron donor, the mixed culture dechlorinated PCE to cis-1,2-dichloroethylene (cDCE) in 24 h. When phenol and glucose were added to the reactor, the mixed culture dechlorinated PCE to cDCE, metabolized the influent phenol, and oxidized 90 percent of the cDCE produced in 24 h. Because both phenol and toluene can induce the enzymes necessary for mineralization of TCE and DCE, an anaerobic/aerobic bioremediation approach has potential application for remediation of groundwater at rail yards co-contaminated with diesel fuel and chlorinated ethylenes.

Changes in soil microbial community composition induced by cometabolism of toluene and trichloroethylene

“…Toluene and TCE co-contaminate sites such as railyards, where toluene enters the soil through fuel spills or storage tank leaks, and TCE through accidental release during its use and disposal by maintenance personnel (Hirl 1998;Sung et al 2003). In other instances of TCE contamination, toluene may be added in order to stimulate cometabolic removal of TCE (McCarty et al 1998).…”

Kinetic analysis of atod-lux bacterial reporter for toluene degradation and trichloroethylene cometabolism

“…At the Savannah River site alone, the DOE estimates there are 4.4 million kg of TCE contaminated soil and groundwater (Hazen, 1991). Hirl (1998) indicated that toluene and trichloroethylene are common cocontaminants at rail yards because of diesel fuel spills and storage tank leakage, in addition to improper handling, storage, and disposal of trichloroethylene used in the maintenance of locomotives.…”

Continuous trichloroethylene biodegradation by Pseudomonas putida F1 in a biofilm reactor and determination of an optimal feeding path via a response surface model

“…9 Pseudomonas putida F1 has been demonstrated to have a high capability to metabolize TCE 8,11 in the presence of toluene, which is also one of the co-pollutants with TCE found in contaminated industrial sites. 3,14,15 However, few studies have been conducted regarding P. putida F1 behavior in biofilm reactors, [16][17][18] especially for aqueous-phase TCE treatment, which was done mostly in batch scales. 19,20 The fundamental issues for a sustained aqueous-phase TCE biodegradation via cometabolism are oxygen limitation, competitive inhibition from the growth substrate, and toxic effect 21,22 from the TCE degradation products.…”