Remediation of gravel railroad tracks (track ballast) in an operational railway
After detecting the presence of a contaminant from an oil spill or drippings at storage or other railroad facilities, damage-specific investigations are carried out. Such preliminary investigations usually allow a reliable estimation of the type and concentration of the contaminant, so that an appropriate biological remediation process can be applied.
The biological treatment is usually carried out by repeated application of water-diluted microorganism suspension and nutrient solution on the track ballast. The mixed cultures of microorganisms used in this technology are isolated from other contaminated railway sites which were remediated and as such, are optimally adapted to the degradation of railway-specific contaminants or a combination of contaminants.
Technology / Features
Our laboratory in Cologne specialises in the isolation, enrichment and cultivation of microorganisms which are able to degrade harmful substances. Such bacteria are naturally present in samples of contaminated soil. For use in our bioremediation procedures, such bacteria are isolated and enriched in large quantities under the best possible growth conditions in our bioreactors.
For the remediation tasks at DB Netz AG (German Railroad Network), mixed cultures and their required nutrients are water-diluted on site. The discharge of harmful substances and nutrients by elution, as a result of the remediation treatment does not occur. The biodegradation of mineral oils below the track area reaches concentrations below threshold target values usually within a single vegetation period and is frequently checked by soil sampling. Since, remediation work is carried out during regular railway operation; interruption of railroad traffic and road surface construction is avoided.
Dipl.-Geol. Dietmar Raffelsieper
phone (02204) 9726-0