Removal of hexavalent chromium of contaminated soil by coupling electrokinetic remediation and permeable reactive biobarriers.
OBJECTIVE
In this study, a novel and ecological alternative have been developed to treat soils contaminated with hexavalent chromium coupling two well-known systems: electrokinetic remediation and permeable reactive biobarriers. The electric field promotes the electromigration of the hexavalent chromium oxyanions towards the anode. The biobarriers were placed before the anode electrode, in order to promote the reduction and retention of the chromium migrating in its direction. Thus, this technology provided a global treatment to soil removal without subsequent treatments of the contaminated effluents.


METHODS
The electrokinetic system was coupled with two different permeable reactive biobarriers composed by Arthrobacter viscosus bacteria, supported either in activated carbon or zeolite. An electric field of 10 V was applied and two different treatment times of 9 and 18 days were tested.


RESULTS
Removal values of 60% and 79% were obtained when electrokinetic treatment was coupled with zeolite and activated carbon biobarriers, respectively, for a test period of 18 day. The reduction of hexavalent chromium to trivalent chromium was around 45% for both systems.


CONCLUSIONS
In this work, two types of biobarriers were efficiently coupled to electrokinetic treatment to decontaminate soil with Cr(VI). Furthermore, the viability of the new coupling technology developed (electrokinetic + biobarriers) to treat low-permeability polluted soils was demonstrated.
Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Braga, Portugal.
B
B
Fonseca
M
M
Pazos
T
T
Tavares
M A
MA
Sanromán
D001173:Arthrobacter; D002857:Chromium / Q000737:chemistry / Q000302:isolation & purification*; D004563:Electrochemistry / Q000379:methods*; D052918:Environmental Restoration and Remediation; D006863:Hydrogen-Ion Concentration; D012989:Soil Pollutants / Q000737:chemistry / Q000302:isolation & purification*; D017641:Zeolites
D012989:Soil Pollutants; D002857:Chromium; D017641:Zeolites; C074702:chromium hexavalent ion