WP10 Remediation Techniques and Strategies
A105 & A106
1:20 PM - 4:40 PM, Wednesday

() Applications of an integrated multi-process phytoremediation system for removal of persistent contaminants from soils.

Greenberg, B1, Huang, X1, Dixon, D1, Glick, B1, 1 Dept. of Biology, University of Waterloo, Waterloo, ON, Canada

ABSTRACT- Phytoremediation of persistent contaminants from soils is clearly an important technology. However, a common problem is that it can be a slow process. To address this problem, we developed a multi-process phytoremediation system (MPPS) with improved and accelerated remediation kinetics. It was found to be effective for removal of polycyclic aromatic hydrocarbons (PAHs), total petroleum hydrocarbons (TPHs) and metals from soil. The techniques applied to realize this were land farming/light exposure, inoculation of contaminant degrading bacteria and plant growth with plant growth promoting rhizobacteria [PGPR]. This resulted in an overall remediation process that was very effective at removal of persistent, strongly bound PAHs and TPHs from soil. For instance in a 4 month period, we were able to remediate 50 % of the PAHs from a 50 year old industrial soil. This soil was from a foundry site that dates back to World War II. Also, in this soil were low levels of metals and evidence of remediation of these metals was observed. Further, the MPPS remediated 90 % of the TPHs from a petroleum land farm soil in 8 months. This soil had been weathered in situ for more than 6 months before remediation was attempted. We have also had success in restoring agricultural soils with high salt (approx. 1 ppt) and herbicide residues. The key element for success of the MPPS was the plant/PGPR interaction, largely due to alleviation of stress ethylene effects. This leads to massive amounts of root biomass in the contaminated soil. The high biomass levels provide a sink for partitioning of contaminants out of the soil and their subsequent metabolism in the plants. We are now performing in situ field tests of the MPPS on oil sludge contaminated soils and herbicide contaminated soils. The results of these field tests will be presented.

Key words: Plant growth promoting rhizobacteria, Remediation, PAHs, Petroleum hydrocarbons

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