Ex situ remediation of chlorophenol contaminated soil: comparison of slurry and two phase partitioning bioreactors

In this work a comparison between a conventional ex-situ method for the treatment of contaminated soil, a slurry bioreactor, and the use of absorptive polymers combined with a biological regeneration of polymer in a Two-Phase Partitioning Bioreactor (TPPB), was carried out. 4-chlorophenol (4CP) and pentachlorophenol (PCP) have been chosen as target compounds and Hytrel(TM)8206 was utilized for the extraction from contaminated soil. Extraction tests reached very high removal efficiencies (>70%), with 24 hours of contact time. Chlorophenols loaded polymer beads, after extraction stage, were added to TPPB bioreactors and a biological regeneration was performed with excellent removal efficiencies for both compounds. The same contaminated soil was treated in a slurry bioreactor (inoculated with the same inoculum): no degradation of PCP occurs during the test while 40 days are required to remove 97% of 4CP.