Challenges facing field applications of electrokinetic bioremediation- Critical
review
Ernest Yanful1, Eltayeb Mohamedelhassan2, and Ikrema Hassan1
1
Civil and Environmental Engineering Department, University of Western Ontario, Ontario, Canada
2
Civil Engineering Department, Lakehead University, Ontario, Canada
Many human activities in our world today can directly result in soil, and/or surface and ground water
pollution. Common types of contaminants include heavy metals, anthropogenic products, and petroleum
hydrocarbons. These contaminants can find their way to a potential receptor through different path ways,
such as improper management of industrial and municipal waste, leaking underground storage tank, and
accidental spills.
In the geotechnical research field, many remediation methods have been developed and implemented for
cleaning up contaminated sites. Among these methods bioremediation stands out for its low cost. There
are a variety of bioremediation techniques (Biopile, Landfarming, Phytoremediation, Bioslurry
Bioventing, etc.) that can be used to remediate contaminated sites. From biological and chemistry point of
view, bioremediation is defined as the employment of indigenous bacteria in a contaminated site to
degrade the pollutions (indigenous bacteria can use pollutant as a food). The basic concept is to stimulate
the growth and metabolism of indigenous bacteria via aeration and addition of nutrients (Biostimulation),
or to introduce new bacteria with superior degradation capabilities to the contaminated site
(Bioaugmentation). The type of soil in a contaminated site usually plays a dominant role in the
effectiveness of this technique. A main challenge facing the implementation of conventional
bioremediation techniques is the difficulty in effectively and precisely delivering nutrients to indigenous
bacteria, particularly in soils with low hydraulic permeability.
Scientist and researchers believe that there want be a single universal remediation technique to remediate
all kinds of contaminants, rather an effective remediation may include two or more methods. In the last
decade, the implementation of bioremediation coupled with electrokinetics has been suggested to enhance
the outcome of bioremediation. This hybrid approach has a potential to restore sites with low hydraulic
permeability where conventional bioremediation technique are deemed ineffective. The transport
phenomenon associated with electrokinetic remediation, namely, electroosmosic flow, electromigration,
and electrophoresis, can be utilized to effectively deliver nutrients to indigenous bacteria in the soils.
Nevertheless, the development of acidic medium near the anode and alkaline environment at the vicinity
of the cathode by electrolysis reactions can create unfavorable condition for bacteria. Controlling pH
gradient in electrokinetics applications is recognized as a major challenge facing this technique. There is
also a concern regarding the availability of power source especially in remote areas with insufficient or
non-existing power lines.
This paper discuss the major challenges facing field application of electrokinetic bioremediation and
underline areas that future research needs to address.
Key words: Bioremediation, Electrokinetic, Biostimulation, and Bioaugmentation.