BIOREMEDEIATION OF CHLORINATED POLLUTANTS BY BIOELECTROCHEMICAL CELLS

THIS PROJECT AIMS TO DEVELOP AND APPLY SUSTAINABLE ELECTROCHEMICAL TECHNOLOGIES TO TREAT GROUNDWATERS CONTAMINATED WITH ORGANOCHLORINE COMPOUNDS. CONTAMINATION OF SOILS, SEDIMENTS, GROUND AND SURFACE WATER CAUSED BY HUMAN ACTION AND LEAKAGES INTO WATER SOURCES HAS BECOME A SERIOUS PROBLEM. IT REPRESENTS A SIGNIFICANT BURDEN FOR SOCIETY BECAUSE FRESH WATER SCARCITY IS ONE OF THE MAJOR ISSUES TO FACE NOWADAYS WHICH HAS BEEN HIGHLIGHTED WITH THE EFFECTS OF THE CLIMATE CHANGE. AMONG ALL WATER POLLUTANTS, XENOBIOTIC ORGANIC POLLUTANTS ARE OF SPECIAL CONCERN DUE TO THEIR PERSISTENCE IN THE ENVIRONMENT, AND THE TENDENCY TO ADSORB ON SOLID MATRICES INCLUDING ORGANIC MATTER WHICH COULD BE TRANSFERRED TO THE LIVING ORGANISM THROUGH THE FOOD CHAIN. HALOGENATED ORGANIC COMPOUNDS IN GENERAL, AND CHLORINATED COMPOUNDS IN PARTICULAR, HAVE BEEN EXTENSIVELY PRODUCED AND USED FOR INDUSTRIAL AND AGRICULTURAL PURPOSES. BUT IMPROPER USE, STORAGE AND DISPOSAL HAVE RESULTED IN GLOBAL CONTAMINATION DUE THEIR CHARACTERISTICS SUCH AS INHERENT STABILITY, BIOACCUMULATION, LOW WATER SOLUBILITY, VOLATILIZATION AND LONG-DISTANCE MIGRATION. AMONG THE DIFFERENT REMEDIATION STRATEGIES, BIOREMEDIATION, WHICH RELIES ON BIOLOGICAL PROCESSES TO DETOXIFY CONTAMINANTS, IS A SUSTAINABLE ALTERNATIVE BECAUSE IT IS LOW COST AND ENVIRONMENTALLY FRIENDLY. IN THE RECENT YEARS, ONE OF THE EMERGING SUSTAINABLE AND VERSATILE TECHNOLOGY TO ENHANCE BIOREMEDIATION PROCESSES IS BIOELECTROCHEMICAL SYSTEMS. TWO TYPES OF SYSTEMS WILL BE EMPLOYED IN THIS PROJECT: (A) MICROBIAL ELECTROLYSIS CELLS (MEC), WHICH CAN USED TO CATALYSE REDUCTIVE DICHLORINATION REACTIONS IN THE CATHODE BY ORGANO HALIDE-RESPIRING BACTERIA BY SUPPLING ELECTRONS VIA HYDROGEN GENERATION THROUGH ELECTROCHEMICAL DE HYDROGENATION, (B) MICROBIAL FUEL CELLS WHERE CHEMICAL ENERGY CAN BE CONVERTED INTO ELECTRICITY. THE USE OF WHITE ROT FUNGI, EXTRACELLULAR OXIDOREDUCTASE ENZYME PRODUCERS, IN THE CATHODE CHAMBER CAN ENHANCE THE REDUCTION OF THE OXYGEN AS TERMINAL ELECTRON ACCEPTOR AS WELL AS EVIDENCE DEGRADATION CAPACITY TO XENOBIOTIC ORGANO- POLLUTANTS. THE MAIN GOAL OF THIS PROJECT IS THE BIOELECTROCHEMICALLY-MEDIATED DEGRADATION OF ORGANOCHLORINES INTO NON-TOXIC PRODUCTS THROUGH TWO DIFFERENT APPROACHES: FUNGAL MICROBIAL FUEL CELLS (F-MFC) AND STIMULATION OF ORGANOHALIDE-RESPIRING BACTERIA WITH ELECTROCHEMICALLY-GENERATED HYDROGEN IN MICROBIAL ELECTROLYSIS CELLS (MEC). LINDANE WILL BE USED AS A MODEL CONTAMINANT BUT OTHER ORGANOCHLORINES WILL BE TESTED. THIS STUDY AIMS TO (1) DEVELOP LAB STUDIES TO EXPLORE THE DECHLORINATION POTENTIAL OF WHITE ROT FUNGI GROWING IN THE CATHODE OF MICROBIAL FUEL CELLS AND, (2) SCALE-UP A MEC FOR AN IN-SITU GROUNDWATER BIOELECTROREMEDIATION OF AN AQUIFER CONTAMINATED WITH LINDANE.