Comparison of pilot-scale bioremediation of PAH contaminated construction rubble with laboratory tests

Bernhard Gemende, Anja Gerbeth, Gerhard Müller, Christina Höse, Jürgen Seidel, Rüdiger Lange and Roland H. Müller 

Abstract
In laboratory investigations indigenous microbial species were isolated, selected and adapted to metabolise contaminants (PAH in the presence of petroleum hydrocarbons) directly in the alkaline milieu. Various strains of Micrococcus sp., Dietzia sp., Rhodococcus sp. and Pseudomonas sp. met the selection criteria of broad profiles in PAH degradation, stable expression of the traits and tolerance to alkaline conditions. At laboratory-scale, tested, specialised alkaliphilic strains were capable of degrading the single PAH contaminants directly on the debris matrix with reduction rates of 50% to 80% in about 100 days.
The corresponding pilot-scale tests showed lower PAH reduction rates of 30% to 60%, with very low values of only about 10% for high molecular weight, i.e. 4- to 6-ring, PAHs. The reasons could be attributed to less optimal homogenisation as well as disadvantageous media and milieu conditions. In addition, comparing laboratory degradation tests with single strains showed indications of the accumulation of toxic PAH metabolic product. 

Key words: bioremediation, construction rubble, polycyclic aromatic hydrocarbons 

Land Contamination & Reclamation, 14 (2), 2006, 252-257 

DOI 10.2462/09670513.761 

Updated: 26-Jun-2006