Tennessee Valley Authority · NYSE:TVC
Tennessee Valley Authority — Technical Presentation (2013)
29 slides from Tennessee Valley Authority's technical presentation, 2013
Slide 1: TVA Kingston Ash Recovery Project, Roane County, TN
TVA Kingston Ash Recovery Project Roane County, TN Craig Zeller, P.E. Remedial Project Manager Superfund Division US EPA Region 4 Zeller.Craig@epa.gov
Slide 2: TVA Kingston Steam Plant
TVA Kingston Steam Plant • ≈ 30 miles west of Knoxville off Interstate 40 • Emory River Mile 2.0 (just above confluence with Clinch River) • Built 1951 to 1955 (initially for DOE Oak Ridge Reservation) • 9 coal fired units • 10 Billion KW-Hrs electricity year (670,000 homes in TN Valley) • 14,000 to
Slide 3: Swan Pond Embayment 1941
TOPOGRAPHICAL MAP ZOTITE
Slide 4: Dredge Cell Area Pre-Spill
Dredge Cell Area Pre-Spill _ 20074 Cell 2 Main Ash Collection Pond Cell 3 Initial Ash Cell
Slide 5: Spill Progression – 12/22/08
Spill Progression – 12/22/08 FILLS IN SWAN POND SLOUGH EMPTIES INTO EMORY RIVER MAIN CHANNEL FILLS IN BERKSHIRE SLOUGH
Slide 6: Dredge Cell Area Post-Spill
Dredge Cell Area Post-Spill
Slide 7: Root Cause Analysis
Root Cause Analysis Kingston Dredge Cell Failure Conditions Increased Loads Due to Higher Fill Hydraulically Placed KIF Failure ; Fill G t Loose Wet Ash & eometry Setbacks Unusually Weak Silt/Ash Slime Foundation
Slide 8: CERCLA Removal Action Strategy
CERCLA Removal Action Strategy (May 12, 2009 AOC) • Phase 1 (Time-Critical Action Removal) – 3.5 million cys removed (excavated and dredged) – 4.0 million tons disposed at Perry County, AL (completed 12/01/10) – May 29, 2010 Emory River reopened • Phase 2 (Non-Time Critical Action Removal) – 2.8 mil
Slide 9: Ash Deposition (Pre-Dredging)
Ash Deposition (Pre-Dredging)
Slide 10: Ash vs. Native Soil Concentrations
Ash vs. Native Soil Concentrations (volume = 3M cys)
Slide 11: Phase 2 Work Description
Phase 2 Work Description • Excavate Ash (Armada of Yellow Iron) – Pan Scrapers – Excavators/ar-tic dump trucks • Short-Term Storage – Dry to Optimum Moisture Content – Lime (5% by weight) • Long-Term Storage in Dredge Cell – Placed in 1 foot lifts – Compacted to 90% proctor – In-situ density/Piezos/
Slide 12: Why Moisture Content Matters
Why Moisture Content Matters
Slide 13: Phase 2 Operations Schedule
Phase 2 Operations Schedule 1 OXI oa 7x Tete Tere et teste Pe rere ee Cae | North Dredge Cell Swan Pond Road Lateral Expansion [Ash Pond Stablltzatlon = = wall = “aes North Embayment | Middle Embayment Dike 2 peeerecrs) oo armete TT Tf LTT Tf North Dredge Cell North/Central Dredge Cell lsouth Dredge
Slide 14: Mechanical Excavation
Mechanical Excavation • East Embayment • Up to 7,500 CY/day productivity • 0.75 million CY excavated • June 2009 – May 2010 (11 months) • North Embayment • Ave 5,600 CY/day productivity • 1.0 million CY excavated • November 2010 – November 2011 (13 months) • Middle Embayment • Ave 2,600 CY/day produ
Slide 15: Ash Stacking
Ash Stacking • “Loose” Volumes Placed/Remaining • Dredge Cell = 2,313,000/192,000 CYs • Lateral Expansion = 1,890,000/Zero CYs • Ash Pond = 375,000/615,000 CYs • Total Ash Placed = 4,578,000 CYs • Total Ash Remaining = 807,000 CYs • 85% Completed
Slide 16: Dredge Cell Cut & Fills
Dredge Cell Cut & Fills Cap Design • Prepare ash subgrade • 40 mil HDPE liner • Drainage layer • 2 ft of clay/topsoil • Vegetative surface 240 Acres Total Cap Placement started Mid-June 2013
Slide 17: Capping Progress
Capping Progress • Production Goal = 2 acres per day • 81 acres of HDPE Liner installed • 60 acres of geo-composite drainage layer • 56 acres of soil cover • On schedule to be ≈50% done by end of 2013.
Slide 18: Slide 18
Slide 19: Perimeter Containment System
Perimeter Containment System • Design based on 3-D Seismic Model (FLAC) – 6.0 earthquake on East TN fault – 7.6 earthquake on New Madrid fault • ≈11,500 linear feet of cell perimeter • 50-70 feet BGS/Keyed 2-6 ft into bedrock • Target Average UCS = 280 psi • Batch Plant for Slurry Recipe (22% blast
Slide 20: Phase 3 – River System SAP
54 Fy AP Parca 01-nn ilar Sen SH TENNESSEE RIVER REACH B: TRM 566.0-565,0—, sone “F i “NW tennessee _——— RIVER REACH A; — TRM 550.0-566.0 Fi EMORY RIVER — REACH © STUDY REACH LEGEND: EMORY RIVER So cinch River TENNESSEE RIVER FIGURE 3-1 REACHES OF THE EMORY, CLINCH, AND TENNESSEE RIVERS KINGSTON ASH
Slide 21: Sampling & Analysis Plan – June 2010
Sampling & Analysis Plan – June 2010 • 2 year, $40M ecological study within CERCLA Eco Risk Framework • >16,000 samples collected; >400,000 analyses • Multiple State/Federal Agencies (TDEC, TWRA, USGS, USACE, ORNL, USFWS) and 10 Universities (NGOs) ABIOTIC • Nature & Extent of Sediment/Ash – Residua
Slide 22: Phase 3 River System Findings
Phase 3 River System Findings • ≈ 510,000 CYs of residual ash dispersed over 200 acres • Co-mingled with DOE legacy contaminants (CS-137/Hg/PCBs) • System is Net Depositional – 1 to 5 feet accumulation over 30 years – Natural mixing/burial expected to reach sediment cleanup goals in 10 to 15 years •
Slide 23: Removal Alternatives Evaluated - August 2012 EE/CA Report
Removal Alternatives Evaluated - August 2012 EE/CA Report • Alternative 1 - Monitored Natural Recovery (MNR) – 30 years of monitoring for sediment, mayflies, benthic/fish communities and sediment transport modeling – Net Present Value = $10 Million • Alternative 2 – Capping • Alternative 2A – Cap al
Slide 24: Community Involvement
Community Involvement • Conducted series of 6 workshops at Roane State CC (March – June 2012) • River System EE/CA Report (HHRA + BERA) released for public comment on 08/10/12 • Initial 30 day comment period extended 30 days to 10/12/12 • Phase 3 River System Action Memo for Alternative 1 – MNR appr
Slide 25: North Embayment
North Embayment then now
Slide 26: East Embayment
East Embayment now then
Slide 27: Swan Pond Embayment Restoration
Swan Pond Embayment Restoration
Slide 28: Swan Pond Embayment Restoration
Swan Pond Embayment Restoration • Phase 1 – Lakeshore Park • Completed August 2012 • Walking trails, fishing piers, courtesy docks & restroom facilities • Phase 2 – Lakeshore Park/Middle Embayment • Boat ramp, walking bridge, trails & Middle Embayment habitat improvements underway • Berkshire Recrea
Slide 29: A Long Ash Day Ahead!
A Long Ash Day Ahead! • 14 technical presentations by a variety of distinguished guests • Fish Health & Reproduction • Human Health Risk Assessment • Sediment Toxicity • Mayflies • Benthic Macro Invertebrates • Selenium • Ecological Risk Assessment/Remedial Goals • Wildlife Exposure/Dietary Models •
Tennessee Valley Authority — Technical Presentation (2013) on 6ix