Treatment Technologies

Treatment Technologies ENVM 644: New Technologies in Environmental Management Dr. Robert Beauchamp

PHYSICAL TREATMENTS • INCINERATION • DESTROYS ORGANIC COMPOUND • CONVERTS LIQUIDS TO SOLIDS & REDUCES VOLUME. • 900 - 1500 DEGREES C • EXAMPLE: ROTARY KILN, LIQUID INJECTION • THERMAL DESPORPTION • VOLATIZES VOC's. • 300-600 DEG. C.

PHYSICAL TREATMENTS (cont) • PYROLYSIS • CONVERTS VOC's TO COMBUSTIBLE, GAS, CHARCOAL, LIQUIDS AND ASH. • 500-800 DEG. C. • VITRIFICATION • HIGH TEMPERATURE ELECTRODES MELT THE WASTE. • IN-SITU OR EX-SITU. • GASES ARE COLLECTED BY A HOOD FOR TREATMENT. • 4,000 VOLTS REQUIRED TO REACH 3,600 DEG. C. • NEED SUFFICIENT GLASS FORMING MATERIAL, DEEP WATER TABLE.

IN-SITU PHYSICAL TREATMENTS (SOILS) • SOIL FLUSHING: • REMOVING SOIL CONTAMINANTS ORGANIC/INORGANIC) USINGWATER FOR TREATMENT. • SOIL WASHING: • SIMILAR TREATMENT USING: WATER, ACIDIC SOLUTIONS, & SURFACTANTS • SOLIDIFICATION/STABILIZATION • POZZOLAN - PORTLAND SYSTEMS (PHYSICAL ENTRAPMENT. SOILS CONTAINING METALS, PCB'S, OIL SLUDGES, VINYL CHLORIDE,RESINS,ASBESTOS, SULFIDES, ETC.) • POZZOLANS INCLUDE: FLY ASH,PUMICE, LIME KILN DUST. • THERMOPLASTIC TREATMENT • ASPHALT OR POLYETHYLENE - BINDS THE WASTE (SLUDGES, PAINT, RADIOACTIVE MATERIALS, METALS & ORGANICS)

THERMAL ENHANCEMENTS • FOCUS: • IN-SITU CONTAMINANT DESTRUCTION • ENHANCE REMOVAL • CONSIDERATIONS: • REMOVE VAPOR PHASE • REMOVE FREE PRODUCT • IN-SITU DESTRUCTION • DECREASE SOLUBILITY • PLAN ON VARIATION IN SOIL PERMEABILITY. • LOW PERMEABLE STRATA CAN BE HEATED QUICKLY. • HEATING IMPROVES REMEDIATION FOR MOST TECHNOLOGIES.

MECHANISMS FOR IN-SITU THERMAL REMEDIATION • ALL PHYSICAL PROPERTIES ARE TEMPERATURE DEPENDENT. • AS TEMP. INCREASES, SO DOES: • VISCOSITY • VAPOR PRESUURE • SOLUBILITY • DIFFUSION RATE • DENSITY DECREASES • EXAMPLES OF TEMP. INCREASES: • LIQUIDS START MOVING • SEMI AND NON-VOLATILES HAVE HIGH VISCOSITIES. • INCREASE VAPOR PRESSURE OF NON-VOLATILES • ENHANCE BIDEGRADATION MICROBIAL SURVIVAL @ 1000C

UNDERGROUND STRIPPING (INCLUDES STEAM & ELECTRIC) • WORKS WELL BELOW GW. • STEP 1: CUT DNAPL FROM PLUME • STEP 2: IMPLEMENT HEATING(STEAM & ELECTRIC ARE PORTABLE) • NOTE: IF IN A HURRY, CONSIDER THERMAL METHODS. • THERMAL REQUIREMENTS: • SET UP THE HEAT. • CAN'T LEAVE ANY COLD AREAS. • NEED RELIABLE EXPERIENCE. • ENERGY FLUX = 1 YD3 NEEDS 100 KWHR = 1000 C. HIGH ENERGY • NEED CONDENSER • NEED TO TREAT WATER • EST. ENERGY COST = $1.00/YD3

UNDERGROUND STRIPPING (INCLUDES STEAM & ELECTRIC) • ADVANTAGES: • ELECTRIC OK FOR SHALLOW SITES. • STEAM GOOD FOR DEEP SITES • OK FOR HIGH CONCENTRATION AND VARIOUS CONTAMINANT TYPES. • COST EFFECTIVE IN REMOVING SOURCE AREA. • DEPTH RESTRICTION - 140 FEETMAY GO DEEPER WITH STEAM. • NOTE:NOT TRIED IN FRACTURED ROCK

UNDERGROUND STRIPPING • STRATIGRAPHY & HYDROLOGY PERMITTING, STEAM CAN DRIVE CONTAMINANT UPWARD. • EXAMPLE:STEAM HEATING SOIL (CLAY) & WATER WITH A CONTAMINANT • RESULTS: • INCREASES PRESSURE & CONTAMINANT CAN BE DRIVEN INTO AN AQUITARD AT LOWER PRESSURES. • ELECTRICAL RESISTANCE TOMOGRAPHY CAN IDENTIFY SPREAD OF STEAM. • STEAM CAN TRACE FRACTURES IN ROCK. • COLD POCKETS WILL LIKELY CONTAIN CONTAMINANT. • NOTE: THE GROUND IS A TERRIFIC SINK FOR HEAT. NEED ENOUGH HEAT.

IN-SITU DNAPL REMEDIATION USING SIX PHASE HEATING • ELECTRODES PLACED IN GROUND • CURRENT IS PULSED BETWEEN ELECTRODES. 150 - 300 VOLTS AT DEPTH. • CAN HEAT EVENLY USING INTERLOCKING ARRAYS. • CAN BE USED WITH STEAM. • CAN PREVENT DNAPL MOBILITY BY HEATING BELOW DNAPL. • ADVANTAGES: • SOIL HETEROGENEITY IS NOT A PROBLEM. • HEATING MAKES CONTAMINANT LESS VISCOUS. • 111 TCE WILL DEGRADE QUICKLY. • DNAPL HEATS QUICKLY, PRODUCES CHLORIDE IONS WHICH CONTRIBUTES TO HEATING FASTER.

IN-SITU THERMAL DESORPTIONUSING THERMAL CONDUCTOR & VACUUM • A QUIET INTRUSIVE TECHNOLOGY • REQUIRES ELECTRICAL POWERED ELECTRODE AND HEATED VACUUM WELLS. • REQUIRED TEMPERATURES - 15000 F AT THE WELLS, 8000 F BETWEEN WELLS. • THERMOCOUPLES INSTALLED TO MONITOR PROGRESS. • DIRECT PUSH WELLS CAN BE INSTALLED 1 PER MINUTE.

RADIO FREQUENCY HEATING • ELECTROMAGNETIC RADIATION • ANTENNAS PLACED IN GROUND &DIRECTED TOWARD CONTAMINANT. • HIGH HEAT > 1000 C; LOW HEAT < 1000 C • NEED SVE SYSTEM/AIR SPARGING INCREASES BIODEGRADATION30 - 400 BEST. • SYSTEM IS MOBILE--TRAILER • ADVANTAGES: • GOOD FOR HIGH CONCENTRATION &VARIOUS CONTAMINANT TYPES. • COST EFFECTIVE • NO DEPTH RESTRICTION • NOTE:STEAM BEST FOR DEEP SITES AND RF NOT TRIED IN FRACTURED ROCK.

IN-SITU CHEMICAL OXIDATION • DELIVERY OF OXIDANTS, i.e. • K PERMANGANATE • Na PERMANGANATE • Ph IS IMPORTANT, = 3 – 12 • Ph DROPS WITH OXIDANT DELIVERY TO SUBSURFACE • AS TEMP. INCREASES, RATE INCREASES.

IN-SITU CHEMICAL OXIDATION (cont) • ADVANTAGES: • FACILITATES OTHER METHODS • PROMOTES RAPID CLEANUP • ENHANCES BIOREMEDIATION • DISADVANTAGES: • DIFFICULT TO DELIVER • HIGH EFFICIENCY NOT A GIVEN • CAN CHANGE SOIL PERMEABILITY • METAL MOBILITY MAY OCCUR • NOTE: MUST MATCH OXIDANT WITH DELIVERY SYSTEM

GROUNDWATER CIRCULATION WELLS • WATER IS RE-CIRCULATED DOWNWARD & CONTAMINANTS EXTRACTED BY AIR INTO A TREATMENT SYSTEM AS GAS. • WELLS ARE SCREENED AT TOP &BOTTOM OF CONTAMINATION. • WELL LOCATION SHOULD BE TANGENT TO GW FLOW. • AQUIFER ANISTROPHY 3 – 10Kh / Kv • DISTANCE BETWEEN SCREENSDEFINES ZONE OF INFLUENCE • DISADVANTAGES: • MAY MOBILIZE CONTAMINANTS • DON'T LOWER WATER TABLE • LOW PERMEABILITY LIMITS EFFECTIVESS OF WELLS.

PERMEABLE WALLS/ BARRIERS • USE OF ELEMENTAL IRON: • REDUCE Cr 3 to Cr 6 • ZERO VALENCE IRON NEEDED FOR TREATING CHLORINATED SOLVENTS. • USE OF LIMESTONE: • RAISE Ph TO CAUSE SORPTION/PRECIPITATION OF LEAD. • BARRIER NEEDS TO BE MORE PERMEABLE THAN FORMATION • NEEDS TO BE REPLACED-10 YEARS

PERMEABLE WALLS/ BARRIERS (cont) • ADVANTAGES: • SYSTEMS EASY TO MONITOR • CAN BE DEEP - 120 FEET • COST EFFECTIVE • ENHANCES BIODEGRADATION • NO O & M COSTS • DISADVANTAGES: • EMPLACING TECHNOLOGY CAN BE CHALLENGING • NOT APPLICABLE TO FUELS & BTEX. • BARRIER NEEDS TO BE MORE PERMEABLE THAN SUBSURFACE

IN-SITU FLUSHING OF NAPL SOURCE ZONES • FOR NAPL's AND DNAPL's • MOST ARE PILOT STUDIES • MUST INCLUDE THE HIGHEST POSSIBLE SOLUBILIZATION AGENTS - ALCOHOLS CAN BE USED.

FRACTURING TECHNOLOGIES TO ENHANCEIN-SITU REMEDIATION • INJECTION RATES > GW FLOW • MOVE CONTAMINANTS OUT & MOVE IN THE REACTANTS.

Treatment Technologies