bund walls
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Tank Storage AssociationTank Storage Association
Conference & Exhibition 22nd September 2011
Innovative solutions using bentonite materials to addressInnovative solutions using bentonite materials to address secondary and tertiary containment issues
Steve FlynnRawell Environmental Ltd
Bentonite for COMAH Containment Issues
Bentonite:
A natural clay which when hydrated forms a barrier to the passage of liquids
Supplied in rolls called a “GCL” laid like a carpet buried with ≥300mm fillSupplied in rolls called a GCL , laid like a carpet, buried with ≥300mm fill
Easily fixes to concrete structures
Self heals minor punctures
Minimal maintenance as membrane always below ground
2 types of GCL – “Dry” – needs to be carefully hydrated on site to functionyp y y y“Prehydrated” – already functions – just need to overlap
Bentonite Lining options “Dry” or “Prehydrated”
“Dry Bentonite”Dry Bentonite
Needs water to hydrate for bentonite to swell and form an impermeable seal
If hydrated with contaminated (site) water - bentonite will not function
Impurities in ground/water can prevent swell and cause failure
Therefore need to import inert material below and above membraneTherefore need to import inert material below and above membrane
Failure = Cation Exchange = causes change from Na+ to Ca++ = shrinks/cracks
Bentonite Lining options “Dry” or “Prehydrated”
“Prehydrated Bentonite”
Prehydrated bentonite is already a formed barrier ie 2.8 x 10-13 m/s
Prehydrated Rawmat® HDB does not need more water to form seal
Liquid polymer protected bentonite unaffected by hydrocarbons
Cation Exchange does not break down Rawmat® HDB – polymer protected
Fast simple installation with general contractors
Can be laid onto contaminated ground – no need for removal to landfill
Simple – strip earth, lay membrane, replace earth to form conforming barrier
Cost effective system – fraction of cost of concrete/clay
Examples of Issues to Consider
Bund walls – Vertical Concrete, Earth Berms, Composite “Hybrids”, , p y
Concrete Supports – Pipe Supports, Staircases, Ring Beams
Tank Bases – Concrete Ring Beams, Compacted Stone “Donuts”
Tank Floor Upgrades – Jacked Tanks, Replacement Floors
Bund Floor Drainage – “Rawdrain” & “PolyStorm”, “ACCO” Drain,
Pi P t ti T ll T il / F d i / i th h E th W llPipe Penetrations – Tell Tails / Feed pipes /pipes through Earth Walls
Tank Chimes – Corrosion Protection to Tank Floors
Sealing to Concrete Bund Wall
Bund wall
Rawmat HDB Type P terminated a minimum of 50mm below ground level and finished with a Rawmat termination bar fixed at 250mm centres with Rawmat soft washer fixings
300mm imported cover material Rawpaste Mastic applied in interface
between Rawmat and concrete bund wall
Compacted sub - base Rawseal TR35 angle filletRawmat HDB Type P laid white t til tnon - woven geotextile uppermost
Earth Bund Wall Sealing Options
Geogrid
Rawmat HDB
300mm
Rawcell filled with concrete at top of bund
300mm
Finish Level
Concrete cap forming anchor trench
Rawcell cellular confinement
200mm thick layer of stone in Rawcell
Rawmat HDB Type PP
of stone in Rawcell
Sealing to Concrete StructuresRawmat HDB Type P terminated a minimum
300mm Imported cover material
Rawpaste Mastic applied in interface between concrete sleeve, Rawmat HDB and Rawseal TR35. Existing concrete
of 50mm below ground level and finished with a Rawmat termination bar fixed at 250mm centres with Rawmat soft washer fixings
Compacted sub - base
Rawseal TR35 angle fillet Rawmat HDB Type P laid white non - woven geotextile uppermost
Tank Base – “Donut”
Rawdrain 444
SEE DRAWING No. 1708RBFOR OVERLAP DETAILS
Rawmat HDB Type PP
Tank Base – Concrete Ring Beam
TankTank
Rawmat HDB
Ring Beam
Rawmat HDB
Tank Floor Upgrades – Jacking & Letterbox
Bund Floor DrainageStone
50mm Stone Layer
Polystorm drain wrapped in terram and half filled with clean gravel
GeotextileRawpaste Mastic
250mm contaminated fill layer
Rawdrain 444400 - 450mm graded
75mm Clean Gravel
Drain Holes
Rawmat HDB Type P
400 450mm graded backfill placed over
Rawmat & Rawdrain
Rawmat Type PPRawdrain 444Compacted sub-base
Pipe Penetration through Earth Bund Wall
Main sheet of Rawmat HDB Type P laid white side facing upwards
Patch of Rawmat HDB Type P. White geotextile removed from and placed clay core side down. Patch must be a minimum of 200mm larger in all directions than diameter of pipe.
300
Rawpaste Mastic applied between sheets and around penetration
Upper white geotextile to be cut back in area to be overlapped by patch
500
500
300mm compacted suitable fill material
Pipe
Collar of Rawmat HDB Type P with the white non-woven geotextile removed and the clay core placed directly to
the pipe and held in place by wire or cable ties.
1
2.5Pipe penetration through earth bund that is no steeper than 1:2.5
Patch of Rawmat HDB Type P. White geotextile removed from and placed clay core side down. Patch must be a minimum of 200mm larger in all directions than diameter of pipe.
Rawpaste Mastic applied between sheets and around penetration
Collar of Rawmat HDB Type P with the white non-woven geotextile removed and the clay core placed directly to
the pipe and held in place by wire or cable ties.the pipe and held in place by wire or cable ties.
Close-Up Isometric View
Sealing Leak Detection Pipes
Rawdrain 444 extended above pipe to protect the Rawmat
Main sheet of Rawmat HDB Type PP with the lower geotextile removed in the area overlapping the first patch piece
Collar of Rawmat HDB Type PP with the geotextile removed from both sides
Rawseal TR35 angle fillet placed tightly around monitoring pipe.
Patch of Rawmat HDB Type PP with the upper geotextile removed
Monitoring Pipe
Rawpaste Mastic applied between all overlaps and applied to pipe
Tank Floor Corrosion Protection - Stopaq®
Tank Floor Corrosion Protection - Stopaq®
Tank
EZ Wrappingband
FN4200 sealant
Backer RodConcrete ring beam
S E l fSome Examples of Prehydrated Bentonite Membranes
used to provide Secondary Containment Solutionsused to provide Secondary Containment Solutions
Case Study: Linking Bund Wall to Floor
Irregular surface overlain with board and loose material smoothed out behind board which is then folded back to provide firm smooth surface for Rawmat HDB Type PP
Concrete cap forming anchor trench
150mm thick layer of concrete in geocell
Rawmat HDB Type PP
concrete in geocell
150mm nails through board into clay
Trench backfilled to bund floor level
As dug backfill
Board extends from base of trench and over slope
Trench cut square and Rawmat HDB Type PP buried in new clay
Imported clay
Case Study: Bund Wall Upgrade & Cut-Off Trench Dig
Case Study: Membrane Installation to Wall & Trench
Case Study: Cellular Confinement filled with concrete
Case Study: Installation to Corners & Completion of Bund
Case Study: Installation of membrane beneath Jacked tank
Case Study: Lapping, Covering of Membrane
Case Study: Extension of Bund - Singapore
Case Study: Installation in Heat, Humidity, Heavy Rainfall
Case Study: Sludge Lagoon Reconstruction - Australia
Case Study: Installation, lapping, Rawgrid
Case Study: Covering, Consolidation, Examination
Case Study: Membrane unaffected, Installation continues,
Case Study: Installation Continues..
Case Study: Sludge Lagoons Reinstated & Operational
US State of Florida
Dept of Environmental Protection
Unconditional Approvalpp
Rawmat® HDB - Prehydrated Bentonite
Bund Floor & Berm Lining
Under Tank Lining
Use in Saline Environments
No Need to Test Ground Conditions
No Need to Flood Bund
Tank Storage AssociationTank Storage Associationgg
Conference & Exhibition 22nd September 2011
Thank you for your attentionThank you for your attention
Questions?Questions?
To find out more, please visit our stand
Steve FlynnyRawell Environmental Ltd
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