Permeable reactive barrier using nanoscale iron particles in As contaminated subsurface

1. Inoculation C-source 산화철 피복 모래 Soil contaminated with As As contamination site Permeable reactive barrier using iron-oxide coated sand Groundwater flow feldspar Removal of As As tolerance microbe As contamination of the groundwater (approximately 20 countries in world) quartz hematite U,As,Au Derived from: www.calacademy.org AGRG Arsenic Geochemistry Research Group Remediation technique for As contaminated soil using indigenous bacteria Permeable reactive barrier using nanoscale iron particles in As contaminated subsurface • Permeable reactive barrier • immobilization of As and • heavy metals in the mining areas • Keeping the groundwater flow • Nanoscale iron particle • innovative barrier material • High surface area and reactivity • Emplacement of nano-particle • Emplacement into reactive • barrier • Finding the optimal condition • Biological treatment • microbe activity depending on C-source • Removal of As by leaching mechanism • Source of arsenic • Natural source: volcanic action, rock erosion • Industrial product: semiconductors, herbicides Low reactivity, bad permeability, high cost of terrestrial excavation in classic PRB Contamination of downstream waters, soil, and terrestrial plants by the release of arsenic and heavy metals The optimal emplacement condition of nano particles : technique of deposition and injection of nano particle Investigation of mobilization of As by increase of microbial activity depending on supplying C-source Techniques development to reduce the extensive excavation, to enhance the reactivity, and to keep the good permeability Development of remediation technique for As contamination soil Expected effect Remediation of As/heavy metal-contaminated subsurface around the metal mining areas Development of Electrokinetic Soil Process to remediate the Heavy metal in soil Phyto-remediation/extraction of toxic elements from soils Phytoextraction Process DC power supply • A cost-effective remediation technique for large areas with low-level contamination • Hyperaccumulators can accumulate elements in the above-ground biomass. • Using traditional harvest process to remove toxic elements in the soils O2 H2 Advantages • Effective in non-permeable soils such as clayey soils • Application to various types of contaminants including organic and inorganic contaminants & radionuclides • Minimization of secondary impacts • Low operational cost H2O H+ OH- metal Cathode Anode Compacted soil cell Electrode cell Electrode cell Phytoremediation cost effective, large areas, public acceptance, hydraulic pumping pressure, after closure maintenance, no excavation, mineralizing organics Soils are contaminated with heavy metals which migrate and threaten human health Soils having low permeability are resistant to in-situ remediation techniques Investigation into the mechanisms of hyperaccumulation of As, Au and U A candidate technology for this type of remedial measure is electokinetic soil flushing Using plants to extract toxic elements from mining sites Removal toxic elements from contaminated sites and recovery of economic elements Various enhancement techniques have been proposed and used

2. MPRG Metal and PAH Research Group Biosorption process using bacteria in metal contaminated groundwater In-situ immobilization of metals by bacteria Biosorption mechanism on the surface of bacteria - entrapment by cellular components - active transport across the cell memebrane - cation exchange or complexation - cell surface adsorption • Dissimilatory metal-reducing bacteria (Anaerobe) • Metabolism with heavy metals in soil & groundwater • Transformation of heavy metals to more stable forms • ※ to more immobile forms of heavy metals • for in-situ immobilization Mechanisms of dissimilatory metal reduction - Direct (biologic) mechanism - Indirect (combined biologic-chemical) mechnism using electron shuttle Biosorption process in batch system No excavation of contaminated soil & groundwater Commercial application for the in low concentrated wastewater Advantages: highly selective, efficient, easy to operate, cost-effective Activation or injection of indigenous metal-reducing bacteria with in-situ Biosorption characteristics of heavy metals by bacteria Immobilization technique using bacteria as effective adsorbent Advantages of cost-effective and environment-friendly remediation technology Application to the removal and recovery of heavy metals from contaminated groundwater in permeable reactive barrier Remediation process monitoring for PAH-contaminated soil using Laser-induced fluorescence(LIF) Bioremediation of Organic-contaminated Soils Using Biosurfactants • Polycyclic Aromatic Hydrocarbons (PAHs) • hydrophobic and most are practically insoluble • persistence in the environment • most exist in strongly adsorbed forms in soils • Biosurfactants • 1) unique chemical structures • (beneficial for remediation) • 2) naturally occurring, biodegradable product • 3) possible to stimulate in-situ production • at the site • most aromatic : exhibit high fluorescence • quantum yields in uv-light, • High selectivity and sensitivity for PAHs • overcome the limitation of traditional analytical method • quantification using time-resolved analysis The highly desirable need for real time, in-situ monitoring techniques for PAH-contaminated soils & remediation process Synthetic surfactant  low bioavailability in biodegradation process due to toxicity Development of monitoring techniques for field application based on the LIF spectroscopy showing the high selectivity and sensitivity for PAHs Biosurfactants  high biodegradation rate due to enhanced solubility and low toxicity Investigation of the effecting variables on the fluorescence intensity and collection of data concerning calibration method and quantification programm Development of the Biosurfactant-Enhanced Bioremediation Technique Feasibility of biosurfactant-enhanced biodegradation process to remediate the PAHs-contaminated soil Development of in-situ monitoring technologies as a quantification/qualification method for the continuous evaluation for PAHs-contaminated soils