P32

ENHANCED BIODEGRADATION OF CHLORINATED ALIPHATICS UNDER METHANOGENIC CONDITIONS USING ELEMENTAL IRON AS THE SOLE ELECTRON DONOR

Since methanogens derive more energy from the use of hydrogen as the electron donor than from other sources as acetate, it has been hypothesized that the conjunctive use of a methanogenic biofilm supported on an iron media will increase the extent of dechlorination of the chlorinated aliphatics over systems incorporating iron alone.

This hypothesis is being tested in continuous flow column reactors with common steel wool as a support media. Disappearance of parent compounds and appearance of transformation products are measured using gas chromatography (GC). Methane concentrations are determined as an indicator of biological activity and are also measured using GC techniques.

Data indicate that the iron-methanogen combination may result in enhanced removal of CT and 1,1,1TCA. Results with PCE are not as promising. This research should be helpful in developing remediation strategies for sites contaminated with chlorinated aliphatics.

Key words: bioremediation, biofilm, chlorinated aliphatics, zero-valent iron