3 September 2015 Tighes Hill Remediation Project...
Transcript of 3 September 2015 Tighes Hill Remediation Project...
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Tighes Hill Remediation Project Update
3 September 2015
• Introduction
• Site History
• Investigation Works and Remediation Planning
• Remediation Project Status
• Community Communications
• Questions?
Agenda
Site History
• 1936 - Atlantic Union Oil Co
petroleum bulk handling Terminal,
Depot vacant
• 1962 – Atlantic changed name to
Esso Standard Oil (Australia) Pty
Ltd, wharf pipeline constructed
• 1980s – Depot started as Esso
trucking terminal
• 1991 – Site purchased by Mobil -
Terminal operations ceased.
Depot continued as Mobil
distributor trucking terminal
• 1994-96 – Depot operations
ceased
• 1997-99 – Demolition – all tanks
removed
• 2008 – Demolition final – removal
of office and gatehouse
7
Investigation Works
Test Pits
Desktop Phase 1 ESA Boreholes/Wells Off-site ESA incl vapour
sampling In Kings Rd
Groundwater Monitoring
To assess:
• background
• history
To investigate:
• geology
• hydrogeology
• site impacts
To understand
• seasonal changes
• trends
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Investigation Works (cont’d)
• LIF=capability to ‘see’ LNAPL with depth
• 41 locations across Terminal
• Used to verify/delineate extent of LNAPL
• Helps better target remediation efforts
Laser Induced Fluorescence (LIF
Some
molecules
emit light
9
Investigation Works (cont’d)
LIF Results
• LNAPL extends through eastern
central part of the Terminal, to max
depth of 2.6m (central part)
• LNAPL occurrence from both LIF
and soil bores has good correlation
• LNAPL largely residualised, not
mobile Detailed investigation =
better understanding
10
Conceptual Site Model (CSM)
Geology and Hydrogeology
• Fill (up to 1.5 m thick) underlain by natural sand/clay
• Shallow groundwater within fill and natural material
Impacts
• LNAPL – isolated well locations at depot (north
west) and terminal (central east)
• Adsorbed and dissolved HC impacts ‘mirror’ the
LNAPL.
• Impacts confined to site and considered stable
Receptors incl qualitative risk assessment
• On-site commercial site users and maintenance
workers
• Off-site commercial users and maintenance workrs
• Off-site residents
• Environment of Throsby Creek
CSM =
picture of
environmental
data gathered
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• Site-specific, assessment of potential risk from site impacts
• Identify hazard (site contamination), identify potential
receptors (humans, environment), assess ways for
exposure to hazard, evaluate risk from exposure
• 4 step process
- CSM review/update
- exposure assessment
- toxicity assessment
- risk characterization and risk based trigger
levels (RBTL)
• Potential for unacceptable risk to commercial site users from LNAPL
impact
• RBTL developed for soil and groundwater to inform future remedial works
• Fate and transport (F&T) modelling showed unlikely negative impact to
Throsby Creek from site impact migration
• QRA incl F&T to be updated post remedial monitoring (if required)
Quantitative Risk Assessment (QRA) &
Ecological Risk Assessment (ERA)
13
• LNAPL impact identified at depot and
terminal
• Potential for unacceptable risk exists to
commercial site users and intrusive
workers on site from LNAPL
• Remediation required to remove this
unacceptable risk
• Remedial trials identified excavation, ex-
situ bioremediation and re-use as
preferred remedial option
• 12 areas (across depot and terminal)
identified for remediation
• Remediation scope and timing in
accordance with VMP
Remediation Action Plan (RAP)
Ready to
commence Site
Remediation
14
Remediation Works Status
Stage 2 -
Principal Works
• 6,000m3
impacted soil
excavated &
treated
• 10,000m3 treated
soil backfilled in
excavations
• Enhanced
environmental
controls:
• Odour
• Vapour
Stage 1 -
Principal Works
• 7,000m3
impacted soil
excavated &
treated
• 3,000m3 treated
soil backfilled in
excavations
• Environmental
controls:
• Groundwater
• Sediment
• Dust
• Odour
• Vapour
• Air Monitoring
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Potential for Asbestos in Soils
• WorkCover NSW
notified & removal
permit obtained
• Licensed asbestos
removal contractor
engaged
• Asbestos Removal
Control Plan (ARCP)
prepared to
document safe work
practices for
handling asbestos
during remediation
and disposal
• Historical filling =
potential for
buried asbestos
• Found at low
concentrations in
depot
(uncontrolled fill)
• Found at very low
concentrations
and limited extent
in terminal
Higher standard of care
adopted = all soils managed as potential
asbestos
ARCP protects health of
workers and members of the public
16
Enabling Works – Making a Start
Concrete breaking &
crushing for
backfilling or disposal
Removal & disposal
of redundant
infrastructure
Environmental controls =
negligible dust or pipe spills
17
Excavation & Treatment of Impacted Soil
• Excavation of
impacted soils
• Transfer to stockpile
for treatment
• Soil mixing with
nutrients
• Completed
excavation & soil
validation sampling
Environmental controls = negligible dust
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Backfilling & Reinstatement
Finished surface
Controlled compaction
Backfilling with
treated soils
Environmental Controls
=
Negligible Dust
19
Environmental Controls: Water Management
(Groundwater Protection)
Product separation
& recovery by
absorbent booms
Product capture &
recovery
absorbent peat
Protection of Throsby Creek &
local users
20
Environmental Controls: Sediment Management
Boundary protection of
storm drains - hay bales and
silt fencing
Protection of internal
storm drains
Protection of Throsby Creek &
Recreational Users
21
Environmental Controls: Dust and Odour
Management
Dust suppression by water
spraying of truck loads
Odour suppressant application to
stockpiles (controls airborne dust too!)
Protection of site workers & local
community
22
Environmental Controls: Dust and Odour
Management
Stockpile covering to
prevent or minimise
dust & odour generation
Protection of site workers & local
community
23
Dedicated Fogger Units
• Odour suppressant spray
mist
• Excavation areas and
boundary locations
Prevent / minimise odour emissions
Environmental Controls: Dust and Odour
Management
24
Environmental Controls - Air Quality Monitoring
• Volatile Organic Compounds (VOC’s)
and odours constantly monitored
• Subjective odour surveys beyond site
boundary in local community
• Asbestos and
VOCs at site
boundary are
monitored
throughout the
working day
25
Stage 2 Remediation Works – What Can
We Do Better to Prevent Odour?
• Odour control ring main along sensitive
boundaries + Met Station
• Enhanced misting effect to prevent
offensive odour
• Apply direct to excavations on digging
• Use in-situ encapsulating agents to
capture vapour
• Apply direct to excavations on digging
• Apply to stockpiles during treatment
Prove to EPA & local
community it works!
Performance Test
26
Community Communications
• Community meetings – share information on remediation activities and
remediation progress, discuss concerns
• Neighbourhood letters – distribute project-related information to a wider
community
• Fact sheet – information on specific issues of interest
• Tighes Hill webpage (in Sep) - keep community abreast of remediation
progress and provide avenue for questions or enquiries
• www.exxonmobil.com.au/tigheshill
• www.mobil.com.au/tigheshill