Limerick Gasworks Remediation 14th September 2017

Con

tent

s

Aerial photograph illust rat ing locat ion of form er gasw orks in relat ion to the River Shannon

In t roduct ion Sit e Hist ory Project Li fe-Cycle Phase 1 Pum p & Treat W orks

Phot ographs

Conclusions

Fut ure Phase 2 St ab i l isat ion / Sol id i f icat ion

W orks

Aeria

l Pho

togr

aph

Aerial photograph illust rat ing locat ion of form er gasw orks in relat ion to the River Shannon

Aeria

l Pho

togr

aph

Site

His

tory

Lim erick Corporat ion set up a gas com pany at Watergate in 1837. The Corporat ion

took over the United Gas Com pany in 1878 and m oved their p roduct ion to Dock Road.

Site com prised an old quarry and agricultural land unt il gas p roduct ion com m enced in 1830 ’s and cont inued to be p roduced from coal at th is site unt il the late 1960 ’s.

In the late 1960 ’s the p roduct ion of gas from coal ceased and p roduct ion from Naptha, an oil p roduct , com m enced. All p roduct ion at the site ceased in 1989 w ith the arrival of natural gas in Lim erick.

Bord Gais inherited the 1.4ha site in 1986.

‘C oal or Tow n G as’ w as p rod uc ed b y h eating c oal in a vessel or struc ture c alled a retort. Th e G as p rod uc ed w ent th rough a num b er of p roc esses to c lean it p rior to leaving th e G asw ork s.

C ok e, ‘C oal Tar’ and ‘S p ent O xid e’ w ere p rod uc ed as b y-p rod uc ts. R em nant c ontam ination w as c aused b y h istoric al sp illages, leak s and d isp osal of b y-p rod uc ts etc .

N um erous und erground struc tures generally p resent d ue to several generations of gasw ork s. Th e m ain c ontam inants generally c om p rise ‘C oal tar’, ‘S p ent O xid e’ and related p rod uc ts.

C ontam inants generally p resent b oth in soils and in und erground tank s. Th ey tend to b e found in m ixtures rath er th an ind ivid ually.

1870

His

toric

al M

ap

1907

His

toric

al M

ap

c197

0 H

isto

rical

Map

c197

0 Ae

rial P

hoto

grap

h

His

toric

al p

hoto

grap

hs

His

toric

al p

ress

cov

erag

e

Proj

ect L

ife C

ycle

Site Investigation and

Risk Assessment

Regulatory approval

and tendering

Desk Top Study review of existing

data

Remediation

Opt ions Appraisal and Design

Opt ions Appraisal and Design

Proj

ect L

ife-C

ycle

Desk Top St udy o Review of all site inform at ion includ ing h istorical m aps,

site m aps, interview of form er Site Manager etc.

Sit e Invest igat ion o Four p revious SI’s undertaken betw een 1995 and 20 0 3

com prising 90 exp loratory holes m ainly target ing form er underground features.

o Com prehensive characterisat ion invest igat ion

undertaken in 20 0 9 com prising 132 sonic d rilled boreholes on a 10 x10 m grid , 1 - 2m into rockhead across the w hole site w ith chem ical analysis carried out every m et re dep th.

Prev

ious

GIs

(pr

e-20

09)

Cha

ract

eris

atio

n G

I (20

09)

Proj

ect L

ife-C

ycle

Det ai led Quant i t at ive Risk Assessm ent (DQRA)

o for b oth h um an h ealth and c ontrolled w aters. o D erives R em ed iation Target V alues (R TV ’s) using

internationally rec ognised m eth od ology, agreed w ith th e E P A .

o M ateria l exc eed ing R TV ’s m ust b e treated or rem oved from

site.

Opt ions Appraisal of rem ed iation tec h nologies o D etailed review of availab le rem ed iation tec h nologies. o S elec tion of p referred op tions – P um p & treat, S tab ilisation/

S olid ific ation , Th erm al d esorp tion or inc ineration .

Reg

ulat

ory

Appr

oval

s Drainage Consent

o Required for d isposal to foul sew er of any ‘c leaned ’ w ater after ap p rop riate treatm ent in an on-site w ater treatm ent fac ility.

o D isc h arge c riteria agreed w ith LC C S anitary D ivision .

Indust r ial Em issions Licence

o Granted b y th e E P A ; w ork s w ould need to b e und ertak en und er a stric t c riteria to p rotec t ad jac ent users and th e environm ent.

o A p p lic ation for surrend er of th e Lic enc e w ould b e

sub m itted to E P A p ost rem ed iation .

Indu

stria

l Em

issi

ons

Lice

nce

Appl

icat

ion

4

Lice

nsee

Ret

urns

- IEL

Num erous Licensee Ret urns are required t o com p ly w it h t he Cond it ions of t he IEL includ ing:- Financ ial P rovisions C R A M P - C losure, R estoration and A fterc are M anagem ent P lan E LR A -E nvironm ental Liab ility R isk A ssessm ent D ata M anagem ent P lan & R ec ord s Fire W ater R isk A ssessm ent B und Integrity A ssessm ents E R P -E m ergenc y R esp onse P roc ed ures A P P -A c c id ent P revention P roc ed ure E M S - E nvironm ental M anagem ent S ystem A E R - A nnual E nvironm ental R ep ort

Proj

ect L

ife-C

ycle

Appropriat e Assessm ent

o AA screening report w as required to assess ecological im p licat ions as part of Hab itats Direct ive and to support a p lanning app licat ion to Lim erick City Council for the p roposed rem ed iat ion w orks.

o Low er River Shannon Special Area of Conservat ion is a Natura 20 0 0 site.

o The screening report considered w hether the p roject w ill have potent ial im pacts upon any Natura 20 0 0 sites.

o All potent ial im pacts of the p roposed rem ed iat ion w ere considered , such as d rainage, t raffic, air quality etc.

o Im pact on clim ate change is not considered to be significant , how ever sustainab le approaches w as m arked favourab ly during assessm ent of cont ractors tenders.

o The AA Screening Report ident ified that p roject w ill not give rise to any significant effects on the Natura 20 0 0 site and hence does not require full Appropriate Assessm ent .

Proj

ect L

ife-C

ycle

Rem ed iat ion

o Tw o phase on-site rem ed iat ion p roject p roposed . Phase 1 com prising Pum p & Treat technique to rem ove DNAPL from underground st ructures/ features (to m inim ise future odour issues).

o Phase 2 com prising stab ilisat ion/ solid ificat ion of upperm ost 3m of m aterial.

Select ion of Rem ed iat ion Cont ract or

o Not ice p laced in the European Journal (OJEU) request ing expressions of interest from cont ractors experienced in sim ilar w orks.

o Selected cont ractors invited to tender for the w orks. Tender docum ents included a detailed Scope, Pricing Docum ent , etc together w ith Planning and Indust rial Em issions Licence (IEL) cond it ions.

Verif icat ion Report

o Details w ork undertaken and the post rem ed iated cond it ion of the site together w ith evidence of com pliance w ith Planning and IEL cond it ions. Form s part of the app licat ion to the EPA for surrender of the IEL.

Phas

e 1

- Con

stra

ints

Pla

n

Phas

e 1

– Pi

lot P

roje

ct Pilot Project

o Undertaken by HBR Lim ited in Sep tem ber 20 13 to estab lish

the m ost effect ive ‘P um p & Treat’ tec h niq ues for extrac ting D N A P L/ c oal tar from und erground features.

o E igh t w ells w ere c onstruc ted to th e b ase of T11 to a llow extrac tion of tar and sub seq uent b enc h tria ls.

o K ey c onc lusions w ere:- O p tim um size of slots in p erforated sec tions of w ells w as

2.5m m , S urfac tants w ould b e effec tive at extrac ting D N A P L

(K em surf S B E 30 w as th e m ost effec tive), and Tem p erature sh ould b e m aintained ab ove 15 oC to ensure

free flow ing D N A P L allow ing op tim um extrac tion rate. M axim um d istanc e b etw een w ells sh ould b e 10 m (ie. 5m

rad ius of in fluenc e). In itia l rec overy rate b etw een 1.44m 3/d ay and 2.59 m 3/d ay

c ould b e ac h ievab le.

Phas

e 1

– Pi

lot P

roje

ct

Determ inat ion of op t im um tem perature for pum ping from

w ells

Determ inat ion of op t im um size of slot for w ells (1m m ,

2m m and 3m m )

Phas

e 1

– Pi

lot P

roje

ct

Determ inat ion of op t im um concent rat ion of

surfactant (0 %, 5%, 10 % and 20 %)

Phas

e 1

– M

ain

Wor

ks

Main Pum p & Treat W orks o Com prised the const ruct ion of Fifty-three 150 m m d iam eter

w ells excavated to the base of: Underground gasholder w ells/ tanks (T11, T28, T13 and T14), Beneath T12 (deep lim estone feature), and The form er quarry (to a dep th of 10 m )

Pum ping f rom w el ls using a var iet y of t echn iques:-

o Pum ping using 75m m d iam eter dow n w ell pneum at ic pum ps, o Flow Path Managem ent (FLM) betw een w ells, o Add it ion of surfactant at a rate of 20 0 lit res per 3m 3 of w ater (approx. 7%), and o In ject ion of heated w ater (boiler capacity of 5m 3 per hour up to 80 OC).

Phas

e 1

– W

ell L

ocat

ion

Plan

Det

ails

of S

igni

fican

t U

nder

grou

nd T

anks

Tank Number & Age

Approximate Diameter

Approximate Maximum Depth of tank (source of data)

Approximate Volume of tank

Backfill?

T7 (pre-1919) 6m 1m (Arup 1996 TP14) 30m3 yes

T11 (Pre-1902)

25m

9.0m

(Mouchel 2009 J06, K04, K05, K06, L04, L05, L06, M05, M06)

2,945m3 yes

T13 (Pre -1840) 10m 4.5m

(Mouchel 2009 E06) 250m3 yes

T14 (Pre-1840) 3m 3m

(professional judgment) 14m3 unknown

T15 (Pre – 1840) 10m 6m

(Mouchel 2009 E07) 375m3 yes

T23 (Pre -1872) 19m 6m

(Mouchel 2009 E08, E09) 1,420m3 yes

T28 (Pre-1872) 16m 4m

(Mouchel 2009 H09, I08, I09) 800m3 yes

T34 (Pre-1919) 4m x 13m

(rectangular tank)

>2.3m (O’Connor 1995)

3m (professional judgment) 156m3 partial

5,990m3 Total

Sche

mat

ic o

f Pum

p &

Trea

t Pro

cess

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

Cl ien t , Cont ract or and

Consul t an t Signage

Aerial phot o of si t e f rom Clayt on Hot el

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

Rot ary d r i l l ing of W el ls using air percussive t echn iques

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

Rot ary Dri l l ing of w el ls using Son ic d r i l l ing Rig

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

Treat m ent Plant cont ained w it h in bund includ ing Set t l ing Tanks

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

DNAPL (Coal Tar) is pumped from the base of wells using pneumatic pumps (by compressed air via

airline manifolds) to separation tanks.

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

DNAPL (Coal Tar) settles to base of large separation tanks.

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

DNAPL (Coal tar) settles to bottom of tank where it is drained off and transferred to Intermediate Bulk Containers (IBC’s)

Granulated Active Carbon (GAC) Filters for treatment of groundwater prior to re-injection

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

DNAPL (Coal Tar) from IBC

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

DNAPL (Coal Tar) ex t ract ed and pum ped in t o IBC

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

A sh ipm ent of IBCs being p repared for t ransport t o Hol land for incinerat ion

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

Fron t loader t ransferr ing IBCs t o con t a iners for sh ipm ent t o Hol land

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

ADR/IDMG – Label l ing/Not i f icat ion

Phas

e 1

– Pu

mp

& Tr

eat P

roje

ct

TranFront ier Sh ipm ent (TFS) Not i f icat ion

Phas

e 1

Inje

cted

/ Ext

ract

ed

Volu

mes

Area

[CATEGORY NAME]

[VALUE]L Area

[CATEGORY NAME]

[VALUE]L

Area [CATEGORY NAME] (exc

Tank 7) [VALUE]L

Tank 7 [VALUE]L

Abstracted DNAPL (L) by location

[CATEGORY NAME]Area A

[VALUE]L

[CATEGORY NAME]Area B

[VALUE]L

[CATEGORY NAME]Tank 7

[VALUE]L [CATEGORY

NAME]Area C (exc Tank 7)

[VALUE]L

Injected Surfactant (L) by location

Cum

ulat

ive

DN

APL

Extra

cted

Fr

om S

ite

0

10000

20000

30000

40000

50000

60000

70000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

DNAP

L Vo

lum

e (L

)

Week No.

Cumulative DNAPL abstraction by Area

Tank 7

Area C (exc T7)

Area B

Area A

Area

A –

DN

APL

Extra

cted

by

Tech

niqu

e

37

56

33

28

50 55

0 0 22

26

23 0

0

214

142

57 0 21 4

263

918

196

877

173

600

99

852

756

252

384

232

142

79 19 0 0 0

0

323

175

64 0

0 0

100

200

300

400

500

600

700

800

900

1000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

DNAP

L Vo

lum

e (L

)

Week No.

Area A DNAPL Abstraction by Method

Pumping

Surfactant

Area

B –

DN

APL

Extra

cted

by

Tech

niqu

e

12 15 28 25 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

972

146

807

111

667

84

370

62

242

18

56

0 0 0 0 0 0 0

1016

960

0

200

400

600

800

1000

1200

0 10 20 30 40 50

DNAP

L vo

lum

e (L

)

Axis Title

Area B DNAPL Abstraction by Method

Pumping

Surfactant

Heating

Area

C (e

x Ta

nk 7

) – D

NAP

L Ex

tract

ed b

y Te

chni

que

1756

1850 1956

1892

1950

1540

0 0

1604 1582 1622

0

1996 1931

1819

1913

1919

2221

2137

1505

1398

1321

1115

1169

1010

880

875

812 784

730

761

599 475

217

159 57 0 0 0

1190

982

731

477

0

500

1000

1500

2000

2500

0 10 20 30 40 50

DNAP

L vo

lum

e (L

)

Wekk No.

Area C (exc Tank 7) DNAPL Abstraction by Method

Pumping

Surfactant

Area

C (T

ank

7) –

DN

APL

Extra

cted

by

Tech

niqu

e

52 48 33 33 23 26 0 0

20 16 6 0 0 0 0 0 0 0 0 0 0 0

895

440

647

164

1012

833

341

628

384 424

154

200

71

0

110

300

517 539 529

481 433

0

200

400

600

800

1000

1200

0 10 20 30 40 50

DNAP

L Vo

lum

e (L

)

Week No.

Tank 7 DNAPL Abstraction by Method

Pumping

Surfactant

Heating

Area

A –

DN

APL

Extra

cted

by

Wel

l 0

100

200

300

400

500

600

700

800

900

1000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

Volu

me

of D

NAP

L rec

over

ed (l

itres

)

No of weeks

Bar chart showing DNAPL recovery in Area A. The first 9 weeks show the set up period with week s 10-28 of the chart showing normal pumping. Weeks 29-36 of the chart shows recovery through flow path

management and surfactant injection.

RWA17

RWA16

RWA15

RWA14

RWA13

RWA12

RWA11

RWA10

RWA09

RWA08

RWA07

RWA06

RWA05

RWA04

RWA03

RWA02

RWA01

Area

B –

DN

APL

Extra

cted

by

Wel

l

0

200

400

600

800

1000

1200

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

Volu

me

of D

NAP

L rec

over

ed (l

itres

)

No of weeks

Bar chart showing DNAPL recovery in Area B (Quarry area). The first 9 weeks show the set up period with week s 10-28 of the chart showing normal pumping. Weeks 29-36 of the chart shows recovery through flow

path management and surfactant injection. RWB18

RWB17

RWB16

RWB15

RWB14

RWB13

RWB12

RWB11

RWB10

RWB09

RWB08

RWB07

RWB06

RWB05

RWB04

RWB03

RWB01

Area

C (e

x Ta

nk 7

) – D

NAP

L Ex

tract

ed b

y W

ell

0

500

1000

1500

2000

2500

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

Volu

me

of D

NAP

L re

cove

red

(litr

es

No. of weeks

HBR005

HBR004

HBR003

HBR002

HBR001

RWC11

RWC10

RWC09

RWC08

RWC07

RWC06

RWC05

RWC04

RWC03

RWC02

RWC01

Area

C (T

ank

7) –

DN

APL

Extra

cted

by

Wel

l

0

100

200

300

400

500

600

700

800

900

1000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

Volu

me

of D

NAP

L rec

over

ed (l

itres

)

No of weeks

Bar chart showing DNAPL recovery in tank 7. The first 9 weeks show the set up period with week s 10-28 of the chart showing normal pumping. Weeks 29-36 of the chart shows recovery through flow path

management and surfactant injection.

RWC19

RWC15

RWC14

RWC13

RWC12

Phas

e 1

Con

clus

ions

Key Conclusions w ere:

o In excess of 70 ,0 0 0 lit res of DNAPL/ coal tar ext racted from underground features, p redom inant ly from T11,

o Significant increases in ext ract ion rates w ere achieved w ith the add it ion of surfactant to in jected w ater,

o Difficulty m easuring DNAPL ext ract ion from all w ells due to ‘c logging’ of flow m eters,

o C h em ic al analysis of ground w ater p re and p ost-GA C treatm ent a llow ed an estim ate of w h en GA C rep lac em ent w as req uired ,

o M ost D N A P L w as extrac ted from a lim ited num b er of w ells loc ated at th e d eep est p oints in th e und erground features (as w ould b e exp ec ted ), and

o V erific ation h oles c om p rising 4 tria l p its and 8 b oreh oles exc avated w ith in und erground tank s T11 and T28 , th e d eep lim estone feature and th e form er q uarry area to d em onstrate th at a ll ‘free p h ase’ D N A P L h as b een extrac ted .

Phas

e 2

Rem

edia

tion

Wor

ks

Phase 2 Cont ract is d ivided in t o 2 d ist inct Sect ional

Aw ards:-

o Sect ion 1 - Enab ling Works inclusive of Pilot Study

2nd sect ion dependent on successful Pilot Study

o Sect ion 2 - Main (Stab ilisat ion and Solid ificat ion) Works

PQQ and Tender stages are com plete and Preferred

Cont ractor w ill be announced once internal Ervia

approval p rocesses are com pleted .

Sect

ion

1 –

Enab

ling

Wor

ks

Scope of Sect ion 1 Enab l ing w orks includes:- 1) Pilot Study (Soil Stab ilisat ion/Solid ificat ion)

2) O’Curry St reet / Dock Road Wall rem oval/ Rep lacem ent w ith

tem porary hoard ing

3) ESB substat ion/ Gas Installat ion (DRI) const ruct ion

4) Soil Rem ed iat ion under Installat ions

5) Slit Trenches ad jacent to Protected St ructures

6) St ructural Integrit y Assessm ent (Dock Road Wall)

7) Stone Arch Rem oval

8) Ivy rem oval

Phas

e 2

- Sto

ne A

rch

Rem

oval

St one arch t o be d ism ant led and p rovided t o Lim erick Civic Trust

Sect

ion

2 –

Stab

ilisat

ion/

So

lidifi

catio

n W

orks

Scope of Sect ion 2 St ab i l isat ion / sol id i f icat ion w orks includes:- o S oil S /S w ork s to c ontam inated soils over up p erm ost 3m

(a long w ith exc avation to b ase of und erground struc tures w h ere >3m ) over a 1.4 h a site (ap p rox. 20 ,0 0 0 m 3).

o S c reen and sort m ateria l into stoc k p iles of h ard , suitab le, rec yc lab le and unsuitab le m ateria l.

o R em oval of rec yc lab le and unsuitab le m ateria ls to ap p rop riate fac ilities.

o B ac k fill site using treated suitab le m ateria l from site, p lus im p orted fill, if req uired .

o C rush ing of h ard m ateria ls and rep lac em ent as h ard stand ing.

o D em olition of existing internal w alls. o C onstruc tion of new m asonry w all a long O ’C urry S treet and

p art of D oc k R oad . o B IM m od el req uirem ent

Indi

cativ

e Fl

owch

art i

llust

ratin

g se

quen

ce o

f ope

ratio

ns

Ackn

owle

dgem

ents

Client – Gas Networks Ireland (Project Management by Ervia, formerly Bord Gais) Consulting Engineers – WSP Ireland Consulting Limited

(formerly Mouchel Ireland Limited) o Tony Brown (tony.brown@wsp.com)

Phase 1 Remediation Contractor – HBR Limited

Phase 2 Remediation Contractor – To be appointed

Limerick Gasworks Remediation August 2017