Tennessee Valley Authority · NYSE:TVC
Tennessee Valley Authority — Technical Presentation (November 2010)
17 slides from Tennessee Valley Authority's technical presentation, Nov 8, 2010
Slide 1: TVA Kingston Ash Recovery Project Regulatory Overview
TVA Kingston Ash Recovery Project Regulatory Overview Craig Zeller, P.E. U.S. EPA Region 4 November 8, 2010
Slide 2: Dredge Cell Area Pre-Spill
Dredge Cell Area Pre-Spill Main Ash Collection Pond Initial Ash Cell
Slide 3: Spill Progression
Spill Progression FILLS IN SWAN POND SLOUGH EMPTIES INTO EMORY RIVER FILLS IN MAIN CHANNEL BERKSHIRE SLOUGH
Slide 4: Dredge Cell Area Post-Spill
Dredge Cell Area Post-Spill
Slide 5: Root Cause Analysis
Root Cause Analysis Kingston Dredge Cell Failure Conditions Increased Loads Due to Higher Fill Hydraulically Placed KIF Failure J Loose Wet Ash Fill Geometry & yy’ Setbacks Unusually Weak Silt/Ash Slime Foundation
Slide 6: Examples of Inorganic Concentrations in Coal Ash
Examples of Inorganic Concentrations in Coal Ash (Ash) Element Avg. ppm Est. lbs. Uses an est. Aluminum 22,700 177 million of 3 million Iron 17,961 140 million CYS of coal ash. Copper 59 462,000 Arsenic 66 515,000 Selenium 6 51,000 Examples of Inorganic Concentrations in Soil (Soil) Element Avg. ppm
Slide 7: Ash Thickness in Rivers
Ash Thickness in Rivers Biggest chunk was 30 feet deep over a mile long in the Emory River
Slide 8: Ash Recovery Project Layout
Ash Recovery Project Layout Non-Time Critical Time Critical
Slide 9: Removal Action Strategy
Removal Action Strategy • Phase 1 (Time‐Critical Action Removal) – 3.5 million cys removed (excavated and dredged) – 3.8 million tons disposed at Perry County, AL (continue thru Dec. 2010) – May 29, 2010 Emory River reopened • Phase 2 (Non‐Time Critical Action Removal) – 2.8 million cys to be remove
Slide 10: No Liner or Leachate Collection
No Liner or Leachate Collection • Groundwater Flow to Site ‐ Silty clay layer beneath site acts as barrier to metal migration ‐ Groundwater does not migrate to drinking water wells, moves downgradient to river ‐ New perimeter dike will reduce lateral groundwater movement ‐ Clay and soil cover will r
Slide 11: No Liner or Leachate Collection
No Liner or Leachate Collection • No Metals Leaching – After over 50 years of groundwater in contact with ash, water quality does not currently exceed drinking water standards – EPA Science Panel and USACE/ERDC studies after spill conclude metals not readily leaching off ash under site‐specific cond
Slide 12: No Liner or Leachate Collection
No Liner or Leachate Collection • No Groundwater Plume – Semiannual monitoring over past 10 years – 2 of 40 samples since release in ballfield exceeded arsenic levels – No arsenic exceedances in past 7 months Downgradient Wells
Slide 13: Dike Construction Before Failure
Dike Construction Before Failure
Slide 14: New Perimeter Dike
New Perimeter Dike LANDFILLED ASH EARTHEN BERM FOUNDATION IMPROVEMENTS WORKING PLATFORM SANDY SILT TO SILTY SAND HYDRAULICALLY PLACED ASH LOPE PROTECTION
Slide 15: Aerial View of Impoundment
Aerial View of Impoundment CHURCH SLOUGH BERKSHIRE SLOUGH (WEST EMBAYMENT) (NORTH EMBAYMENT) SWAN POND ROAD PLANT INTAKE CHANNEL CLOSED DREDGE CELL SWAN POND CIRCLE ROAD CLOSED ASH POND DIKE C EMORY RIVER STILLING POND
Slide 16: Phase 3 River System Sampling & Analysis Plan
Phase 3 River System Sampling & Analysis Plan • Presentations to Follow: – Dennis Callaghan, Environmental Standards – Data Management – Steve Scott, US Army COE/ERDC – Ash Fate & Transport Modeling – Mark Chappell, US Army COE/ERDC – Geochemical Investigations – Mark Greeley, ORNL – Fish Reproducti
Slide 17: Questions?
QUESTIONS?
Tennessee Valley Authority — Technical Presentation (November 2010) on 6ix