Demonstration of soil bioremediation technology enhanced by cyclodextrin
Éva Fenyvesi, Laura Leitgib, Katalin Gruiz, Gábor Balogh and Attila Murányi

As part of the MOKKA project, the innovative technologies that had been demonstrated in field experiments were evaluated. The in situ cyclodextrin-enhanced soil-bioremediation technology developed in Hungary is a combination of (1) in situ bio-venting based on biodegradation in the unsaturated soil zone; (2) ex situ physico-chemical treatment of groundwater; (3) impulsive flushing of a three-phase soil. Randomly methylated beta-cyclodextrin (RAMEB) is used for enhancing the biodegradation and solubilization of hydrocarbon contaminants.

The technology was demonstrated in an abandoned fuel station for agricultural machines. Integrated methodology, which consists of physico-chemical, biological and ecotoxicological methods, was used to characterize the soil processes. In order to monitor the technology, the mobile soil phases – soil gas and groundwater – were frequently analysed. Soil sampling, however, was limited to the beginning and end of the technology’s application.

The field experiment demonstrated that addition of cyclodextrin and nutrients has a synergistic effect on the soil microflora, resulting in enhanced removal of pollutants – both from the saturated and unsaturated soil zones.

The MOKKA technology verification system was used for the evaluation of RAMEB-enhanced bioremediation. The material balance and quantitative risk assessment proved the efficacy of the technology. A cost–efficiency analysis showed that the extra cost of RAMEB as an additive could be paid for by the time saving. A SWOT (Strengths–Weaknesses–Opportunities–Threats) analysis presented the beneficial features of the technology, although it does also have some disadvantages, such as the aforementioned relatively high price of RAMEB.

Key words: bioventilation, enhanced natural attenuation, hydrocarbon-contaminated soil, randomly methylated b-cyclodextrin, technology monitoring

Land Contamination & Reclamation, 17 (3-4), 611-617

DOI 10.2462/09670513.977

© EPP Publications Ltd 2009

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