remediation of gas stations: sustainability assessment …sustrem2014.com/theme 2/3...

The 3rd International conference on Sustainable Remediation

Lanari C., Ambrosini P., Patata L., Crimi G., Ragni P., Schillaci P.

Saipem spa, via Toniolo, 1 – Fano (PU)

The 3rd Sustainable Remediation Conference – Ferrara (Italy), September 17-19, 2014

Remediation of gas stations: sustainability assessment of Excavation and removal of

contaminated soil (Tools, Metrics and Indicators)

Agenda

Ø  Vadose zone remediation technologies Ø  Applicability of excavation and

removal of contaminated soil Ø  Case-study Ø  LCA evaluation (methodology and

results) Ø  Conclusions


Vadose zone remediation technologies


How to select Technologies for soil remediation in vadose zone? Current regolations reference: D.Lgs. 152/06 Potentially applicable Technologies for remediation must refer to the following criteria:

•  protection of both environment and human health

•  achievement of remedial objectives •  long and short-term effectiveness

•  ease of implementation and management

•  minimal environmental impact

•  economic aspects

•  degree and extent of contamination •  recommendation of public autorities



Gas stations characterized by: •  limited operational area •  limited time of operation •  limited invasiveness required •  contamination from refinery products

such gasoline and diesel •  site rebuilding, in this case remediation by excavation could take

place simultaneously with rebuilding activities

Preference is given to technologies of proven effectiveness, applied extensively in numerous situations

Which Technologies are used frequently for soil remediation in vadose zone?



Soil Vapor Extraction (SVE) / Bioventing (BV)

Rif: US-EPA, 1995

Multi Phase Extraction (MPE)

Rif: Schema del sistema di TPE (Da: US-EPA, 1997)

Excavation and transport to disposal or reuse after treatment

Bioremediation (BIOPILE)

Applicability of excavation and removal of contaminated soil


Gas service station: CLOSED SITE 0 Excavation is not allowed 1 Limited extension of the remediation area 2 Need to restitute the area within a short period of time 3 High concentrations in the soil compared to remediation goals 4 Soil with low permeability or high degree of heterogeneity 5 Low depth of contamination

When this approach is preferred compared to other remedial Technologies?

Applicability of excavation and removal of contaminated soil


Gas service station: OPERATING SITE (...) (…)

Presence of structures and/or substructures hindering the excavation

Site rebuilding (in this case remediation by excavation could take place simultaneously with the rebuilding activities)

Impossibility of interrupting commercial activity for the time required to remove contaminated soil

Case-study 1


CLOSED SITE (small-sized intervention), some information •  Remove of all structures above- and below -ground •  Groundwater table between 9 and 14 m below g.l. •  Hydrocarbon contamination at 4 m below g.l. = 11083 mg/kg •  CSR (Remedial objectives) for Hydrocarbon = 3808 mg/kg •  Contamination area = 30 m2

Selected applicable technologies •  Excavation with sheet piles and transport to disposal

•  Excavation without sheet piles and transport to disposal

•  Soil Vapor Extraction (SVE) / Bioventing (BV)

Case-study 1


Excavation with/without sheet piles and transport to disposal ACTIVITIES VEHICLES, MATERIAL AND ENERGY

Installation of temporary retaining walls in the excavation

Sheet piles, pile-driver, truck

Soil excavation Excavator, Loader, Truck Soil storage in the site (include preparation of the area)

Geotextile, Backfill, HDPE, LDPE Excavator, Truck

Soil disposal Truck, landfill Monitoring, refilling and area restoration Quarry material, Truck, Excavator, automobile

Case-study 1


Excavation with sheet piles and transport to disposal

MAX EXCAVATION

DEPTH (m below g.l.)

VOLUME OF SOIL TO BE EXCAVATED

(m3)

VOLUME OF CONTAMINATED

SOIL TO DISPOSAL (m3)

VOLUME OF NON CONTAMINATED SOIL FOR REUSE

DIRECTLY ON SITE (m3)

5 160 35 125

1÷2 weeks

Case-study 1


Excavation without sheet piles and transport to disposal

MAX EXCAVATION DEPTH

(m below g.l.)


(m3)

VOLUME OF SOIL TO DISPOSAL

(m3)

VOLUME OF SOIL FOR REUSE


5 760 410 350

3÷4 weeks

Case-study 1


Soil Vapor Extraction (SVE) / Bioventing (BV)

ACTIVITIES VEHICLES, MATERIAL AND ENERGY

Piezometers PVC, Filter pack, Cement, Bentonite Truck, Drilling machine, Landfill

Suction Blower, Truck Interconnecting Mini-excavator, Loader, HDPE, Steel, Truck,

Landfill

Gas treatment Condensate separator, Transfer pump, Tank, GAC Filters, Truck, Landfill

Monitoring and inspection soil after treatment

Cement, Bentonite, Truck, Drilling machine, automobile

18 monthsSVE +

6 months BV

Case-study 2


CLOSED SITE (avereged-sized intervention), some information •  Removal of all structures above- and below -ground •  Water table between 4 and 6 m below g.l. •  Hydrocarbon and BTEX soil contamination at buried tanks level •  Hydrocarbon, BTEX and MTBE contamination in groundwater •  Contamination area = 1260 m2

Selected applicable Technologies •  Excavation and transport to disposal

•  Excavation and reuse after treatment (BIOPILE)

•  Multi Phase Extraction (MPE)

Case-study 2


Excavation and transport to disposal ACTIVITIES VEHICLES, MATERIAL AND ENERGY

Soil excavation Excavator, Loader, Truck Suction Pump, Storage tank

Soil storage in the site (include preparation of the area)

Backfill, HDPE, New jersey, LDPE, Excavator, Truck

Soil disposal Truck, Landfill Monitoring, refilling and area restoration Quarry material, Truck, Excavator, Automobile

Case-study 2


Excavation and transport to disposal

MAX EXCAVATION

DEPTH (m below g.l.)


(m3)

VOLUME OF CONTAMINATED

SOIL TO DISPOSAL (m3)

VOLUME OF NON CONTAMINATED SOIL FOR REUSE


5 4880 3800 1080

1÷2 months

Case-study 2


Excavation and reuse after treatment (BIOPILE) BIOPILE ACTIVITIES VEHICLES, MATERIAL AND ENERGY

Soil transport and unloading Truck Soil movement Backhoe Soil sieving Sieving system Pile construction PE pipes coated with coconut fiber,

Loader Pile humidification Water solution Pile oxygenation Blower Pile dismantling Backhoe Soil transport to reuse Truck

2÷3 months

Case-study 2


Multi Phase Extraction (MPE) ACTIVITIES VEHICLES, MATERIAL AND ENERGY

Piezometers PVC, Filter pack, Cement, Bentonite Truck, Drilling machine, Landfil

Suction High-vacuum pump, Phase separator, Transfer pump, Tank, Truck

Interconnecting Mini-excavator, Loader, HDPE, Truck, Landfill Gas treatment GAC Filters, Truck, Landfill Water treatment GAC Filters, Truck, Landfill Monitoring and site close after treatment

Cement, Bentonite, Truck, Drilling machine, Landfill, automobile

36 months

LCA (methodology and results)


What is LCA Life Cycle Assessment is a quantitative technique for assessing the environmental aspects associated with a product or system or process over its life cycle, standardized by ISO of 14040 series.

§  identifying opportunities to improve the

environmental performance of products at various points in their life cycle.

§  support decision-makers in industry,

government and other bodies (e.g. for the purpose of strategic planning, priority setting, product or process design)

§  marketing and procurement (e.g. green procurement, implementing an ecolabelling scheme, making an environmental claim, or product declaration



How LCA works Goal and scope definition

Intended application, audience, product system, functional unit, data required, system boundary, limitations ….

Inventory analysis Energy and material inputs. Products, co-products and waste. Emissions to air water and soil

Impact assessment Impact categories, indicators and characterization models, Results

Interpretation Findings are considered together and consistent with scope and goal



•  Preliminary comparison of remediation technologies in two case studies

•  The functional unit is 1m3 of contaminated soil •  Data quality: project data

Goal and Scope

Inventory •  Simapro V7.3.3 •  Ecoinvent V2.2

Impact Assessment •  IPCC 2007 GWP 100 •  ReCiPe endpoint (H)



LCA Case study-1 IPCC 2007 GWP:characterization The least impacting technology is excavation and disposal with sheet piles because, compared to the solution without sheet piles, the volume of soil to be excavated and transported to the disposal site is substantially reduced.

The GWP is equal to 974 kg CO2eq, about one third of the highest impacting solution The SVE technology generates a high global warming potential, similar to that determined by excavation and disposal without sheet piles.



LCA Case study-1 IPCC 2007 GWP:contribution analysis

Contribution analysis shows the environmental impact of single processes

For all technologies the processes with the highest impact are those tied to the consumption of fuel for motors or for energy production



LCA Case study-2 IPCC 2007 GWP:characterization The least impacting technology is MPE: 124 kg CO2eq/m3. The difference among technologies for this application is limited. In terms of GWP the benefit of reusing decontaminated soil is low.

The amount of CO2eq emitted is much lower than in case study C1, both for a s c a l e f a c t o r a n d b e c a u s e t h e contaminated soil is more confined. Consequently the relationship between moved and decontaminated soil is minor.



LCA Case study-2 IPCC 2007 GWP:contribution analysis

Contribution analysis shows the environmental impact of single processes

Transport is the process with the highest impact in the excavation and disposal technology. For MPE the greatest emissions are determined by

the consumption of electric energy



LCA Case study-1 ReCiPe 2008 (H) H/H damage assessment and

normalization

Damage assessment

Normalization

Even with ReCiPe, excavation and disposal with sheet piles is the least impacting technology (same result obtained with IPCC method). The highest impacting

technology is excavation and disposal without sheet piles. The SVE technology presents intermediate impact.



LCA Case study-2 ReCiPe 2008 (H) H/H damage assessment and

normalization

Damage assessment

Normalization

The results obtained using the ReCiPe model are similar to those of the IPCC model. The least impacting technology is MPE, but the difference among the three

technologies is neglectable.

Conclusions In some cases, excavation and removal of contaminated soil is necessary (the best technology): • need to restitute the area in a short period of time; • high concentrations in the soil compared to remediation goals; • site rebuilding (remediation by excavating contaminated soil could take place simultaneously with the rebuilding activities).

Based on the results of LCA Case-study 1 (IPCC 2007 and ReCiPe 2008), the excavation and removal technology is less impacting than SVE.


Conclusions The results obtained with LCA Case-study 2 (IPCC 2007 and ReCiPe 2008) showed that the technology with the lowest impact is MPE, although the difference with excavation and removal is minor. Reuse of decontaminated soil (with BIOPILE treatment ex situ) produces a lower benefit compared to disposal in a landfill. With reference to MPE and SVE technologies , based on the contribution analysis we can conclude that the highest impact is caused by the electric power needed to charge the systems. Therefore, it could be both interesting and convenient to use machinery with highly efficient electric motors and limited consumption, or renewable energy.


thanks / authors details

Paolo Ambrosini [email protected]

www.surfitaly.it

www.sustrem2014.com

We wish to thank Paolo Ricci and Euro Buongarzone for their collaboration

(FAPLEN Department, Saipem spa)

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