Principles and Fundamental Interactions of Electrobioremediation

The electrobioremediation tetrahedron (Fig. 18.1) attempts to conceptualize the relevant processes for subsurface bioremediation, that is, the impact of an electric field on the microbial subsurface habitat and the mutual interactions involved. The following sections will unfold the four sides of the electrobioremediation tetrahedron and discuss the relevant interactions with a special emphasis on the biodegradation of hydrophobic organic compounds in subsurface systems exposed to DC electric fields. 

The capacity of an environment to provide a chemical at a constant rate may become limited due to depletion of labile pools of the chemical. This has inspired the differentiation of an immediate bioavaUability [the freely dissolved compound immediately ready for uptake (Reichenberg and Mayer, 2006)] from a potential bioavailability, which has been named bioaccessibility (the compound that may become bioavailable by, e.g. dissolution, or desorption over time) (Semple et ai, 2004). In this concept, the bioaccessible compound is a fraction of the total compound and appears to be an appropriate descriptor of the possible degradation end point. 

The principle goal of electrobioremediation is therefore to make bioaccessible compound, nutrient, and TEA fractions bioavailable and consequently increase biotransformation rates (Fig. 18.3). The following chapter will specify the impact of DC fields on bacterial mobilization in and deposition to subsurface matrices (Fig. 18.1b). 

Overall, it appears that the effects of electric fields on detachment, adhesion, and biofilm formation on electrodes are a result from electric current exchanged rather than the electric potential applied (Fig. 18.1b). 

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