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This study discusses factors affecting various processes involved in bioremediation coupled with electrokinetics. The study presents innovative solutions, and proposes new directions. Environmental conditions that have an influence on the characteristics, behavior, and metabolism of indigenous microorganisms are presented. The discussion focuses on overcoming the unfavorable conditions created by electrolysis reactions, prolongation the survival of the microbes at contaminated sites, increase of microbial enzyme secretion, improvement of the indigenous bacteria metabolic pathways, and exploration of metagenomics resources from soil biota. The challenge facing the implementation of conventional bioremediation techniques in precisely and effectively delivering nutrients to indigenous bacteria, particularly in soils with tortuous paths and low hydraulic conductivity is discussed. Current knowledge in application of enhanced biostimulation using electrokinetics is reviewed. The implementation of bioaugmentation in bioremediation coupled with electrokinetics to enhance the outcome of bioremediation is presented. Effects of phenomena associated with electrokinetics in the hybrid remediation approach are discussed.

Constructed wetlands (CW) is an environmentally friendly technique for removing pollutants from wastewater and has been applied to municipal wastewater, petroleum refinery wastewater, agriculture drainage, acid mine drainage, etc. The past decade has seen a remarkable number of innovations in the exponentially growing field of microbiology. This manuscript covers a critical review of key aspects of CW, such as various types of CW, the contaminants and their removal mechanisms, degradation pathways, challenges and opportunities, materials, applications, and theory with a focus on recent advances in the last three decades. In addition, an attempt has been taken to project future advances in the field of CW and facilitate these advances by framing key unsolved problems in CW. Guidelines are prepared for the fast-growing CW field through the standardization of key design aspects. This review covers the evaluation of the current state-of-the-art of CW technology and provides definitions and performance metric nomenclature in an effort to unify the fast-growing CW community. It also contains an outlook on the emerging trends in CW and proposes future research and development directions.

This experimental study used solar cells to generate electric field for electorkinetic remediation of a soft clay soil contaminated with copper. Three solar cell panels with peak outputs of 13.5, 27, and 41 V were connected to identical electrokinetic cells to investigate the effectiveness of electrokinetics to remove the copper after 168 hr of remediation. A control test was carried without electric field to provide a baseline data. The results showed that solar cells can provide sufficient electric field for electrokinetic remediation. It was found that electroosmosis was effective in removing water from the contaminated soil while the removal of copper was primarily due to electromigration. The removal efficiency was proportional to the applied voltage and distance from electrode. The maximum removed copper was 86% of initial concentration occurred near the anode.

This chapter discusses the use of bioremediation and phytoremediation coupled with electrokinetics and presents the elements contributing to the success of the remediation process. A deep discussion and an overview of the current advancement in the biotechnologies are outlined in details. Innovative solutions for challenges facing the field application of the new technology are presented and new directions are proposed. A careful review for contaminated site conditions including pH, temperature, and other factors influencing the behavior of microbial community are presented. Great deal of discussion is around overcoming the adverse effect of electrolysis reactions, which is a by-product of electrokinetics. The discussion includes prolonging the survival of the indigenous bacteria, increase of microbial enzyme secretion, improvement of the indigenous bacteria metabolism, and exploration of metagenomics resources from soil biota. The challenges facing the field application of bioremediation and phytoremediation including the delivery of the electron donors and/or acceptors and nutrients to microorganisms involved in the biodegradation, particularly in clay soils, which has very low hydraulic conductivity, is discussed. The use of electrokinetics in biostimulation application to enhanced degradation of organic pollutant is reviewed. The implementation of bioaugmentation in bioremediation coupled with electrokinetics to enhance the outcome of bioremediation is presented.