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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

Tighes Hill former Terminal & Depot

• 3.7 ha site located

at 110 Elizabeth

Street, Tighes Hill

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

Terminal & Depot (looking SE)

Entrance to Terminal - 2008

• Office and Gatehouse prior to demolition

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

8

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

11

Remedial Pilot Trials

Pump & treat MPVE

Ex-situ Bioremediation

Try before you

buy

12

• 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

15

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

18

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

Questions?