Sustainable remediation of recalcitrant organic carbon contamination utilizing a Bio-electrochemical system (BES)

Abstract

This study focuses on the advanced, low-cost, and eco-friendly approaches for the remediation and characterization of recalcitrant organic carbon contamination with a complex nature that has been in the environment for a long time. For example, environmental concerns regarding effective bioremediation applications include contaminated soils with crude oil dominated with petroleum hydrocarbons and mature landfill leachate pollutants. Treatment methods based on the biological aspects were widely used by biodegradation and natural attenuation approaches. However, these methods may have challenges regarding the treatment efficiency of complex and recalcitrant organic pollutants. The recent research opens the opportunity for further questions to adopt these eco-friendly bioremediation methods in advanced applications on decontamination and monitoring recalcitrant contaminants in real time. Engineers and remediation practitioners try to develop long-term enhanced biodegradation methods and provide monitoring natural attenuation tools. The microbial-induced electron transfer based on redox reaction in contaminated land or groundwater can act as biogeobatteris based on the natural biogeochemical responses. Science and research were able to perform this concept in microbial fuel cell (MFC) or Bio-electrochemical system (BES). BES is an engineered system that manipulates the ability of indigenous microorganisms to degrade pollutants and simultaneously generate electricity. BES is considered a promising technology for the bioremediation of different pollutants at low cost and environmentally friendly. Laboratory and pilot scales BES investigations were performed in this study to be further adopted commercially based on the technology readiness level (TRL). The operational conditions of BES are a crucial component to understanding the mechanisms of pollutant removal by a BES, and this study investigates the ionic strength limits on the electrochemical effect and the microbial ecology activities by novel Winogradsky and BES applications. The innovative use of engineered graphite BES on soil contaminated by crude oil following the Gulf War in 1991 sheds important light on the effectiveness of BES treatment and the interactions between microbial populations in such old-age pollutants. Hybrid biodegradation based on BES and adsorption mechanism by granular activated carbon (GAC) was a new strategy to optimise the system treatment efficiency on old-age landfill leachate pollutants. Emerging alternative adsorbents coupled with BES rather than GAC were also investigated in this study by utilizing biochar and hydrochar materials, representing the original work of this project. BES and a modified anode based on composite carbon-based materials can act as biosensor tools to monitor the bioremediation by observing the electrical responses (voltage, current, and power) to determine the microbial interactions and bioelectrochemical activities. An advanced and sustainable-engineered tank experiment on a pilot scale was tested in this study for applying a BES-based permeable reactive barrier (PRB) to monitor landfill leachate pollutants and determine the treatment efficiency on a larger scale. This study contributes to knowledge by the novel application of Fourier transform infrared spectroscopy (FTIR) and chemometrics tools on BES performance efficiency in treatment methods. Overall, this study aimed to understand better the BES based on the removal mechanism for recalcitrant organic pollutants that are challenging for bioremediation treatment strategies, providing valuable insights into the advancement of BES technique and microbial role in biodegradation.

Thesis is embargoed until 31 December 2028.

Date of Award	Dec 2024
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Rory Doherty (Supervisor) & Deepak Kumaresan (Supervisor)