Enhancement of gasworks groundwater remediation by coupling a bio-electrochemical and activated carbon system

Panagiotis Kirmizakis,Leonid Kulakov,Carlos A Mendonça,Rory Doherty,Ulrich S Ofterdinger,Ricardo Costeira,Chris C R Allen

doi:10.1007/s11356-019-04297-w

Abstract

Here, we show the electrical response, bacterial community, and remediation of hydrocarbon-contaminated groundwater from a gasworks site using a graphite-chambered bio-electrochemical system (BES) that utilizes granular activated carbon (GAC) as both sorption agent and high surface area anode. Our innovative concept is the design of a graphite electrode chamber system rather than a classic non-conductive BES chamber coupled with GAC as part of the BES. The GAC BES is a good candidate as a sustainable remediation technology that provides improved degradation over GAC, and near real-time observation of associated electrical output. The BES chambers were effectively colonized by the bacterial communities from the contaminated groundwater. Principal coordinate analysis (PCoA) of UniFrac Observed Taxonomic Units shows distinct grouping of microbial types that are associated with the presence of GAC, and grouping of microbial types associated with electroactivity. Bacterial community analysis showed that β-proteobacteria (particularly the PAH-degrading Pseudomonadaceae) dominate all the samples. Rhodocyclaceae- and Comamonadaceae-related OTU were observed to increase in BES cells. The GAC BES (99% removal) outperformed the control graphite GAC chamber, as well as a graphite BES and a control chamber both filled with glass beads.

Highlights

Effective management of groundwater contamination requires the development of sustainable remediation technologies (Arias Espana et al 2018; Ellis and Hadley 2009; Nathanail et al.Responsible editor: Bingcai Pan Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.2017)
The larger surface area may be responsible for the lower resistivity of the load for the granular activated carbon (GAC) bio-electrochemical system (BES) compared with the glass beads BES
The electrical output from the GAC BES was greater than the glass beads BES due to the greater available surface area of the GAC that acted as the anode electrode

Summary

Introduction

The modification and optimization of socially accepted remediation technologies, such as sorption media into newer technologies that enhance and monitor degradation in near real time, make them ideal candidates as sustainable remediation technologies. This can be in the form of an engineered container or chamber that contains the method of remediation, such as sorption using GAC (Guerin 2008), other porous media (Merino et al 2016), or bioremediation with the addition of nutrients/inoculants (Kuppusamy et al 2016). With in situ remediation systems, similar engineered chambers can be found in reactive cells of various types of permeable reactive barriers (Gibert et al 2007; Davis et al 2010). We propose that the engineered chamber that houses the remediation technology

Methods

Results

Conclusion