Guy Lavoie, C.E.T. Project Director

Transcription

1 Guy Lavoie, C.E.T. Project Director Optimization of Soil and Groundwater Remediation at Former Gas Station and Adjacent Properties, Using a Combination of In Situ and Ex Situ Technologies

2 Presentation Overview Site Description Applicable Legislation Site Environmental Background Challenges Remediation Technologies Results Conclusions Questions

3 Site Description Applicable Legislation Site Environmental Background Challenges Remediation Technologies Results Conclusions Questions

4 Site Location Val d Or

5 Site History Restaurant Former gas station Restaurant House 1 Street 1 House 2 House 3 House 4 Bank House 5 House 6 Street 2

6 Site History Contamination sources Five underground fuel tanks Restaurant Aboveground heating oil tank Automatic car wash Avenue Office Garage including oil furnace and compressor Gasoline pump island Street 1

7 Site Description Restaurant Former gas station Commercial House 1 Street 1 Avenue Restaurant House 2 House 3 House 4 Residential Bank House 5 House 6 Street 2

8 Site description Initial contaminated zone??? Restaurant Depth: 0 to 7 m Former gas station Depth: 4 to 7 m House 1 Initial area with contaminated soils??? Restaurant Street 1 House 2 House 3 House 4 Non impacted Borehole Bank House 5 House 6 Street 2

9 Site description Initial contaminated Restaurant zone??? Initial area with contaminated soils Former gas station??? Restaurant House 1 Street 1 Initial area with free product House 2 House 3 House 4 Bank House 5 House 6 Street 2

10 Site Description Applicable Legislation Site Environmental Background Challenges Remediation Technologies Results Conclusions Questions

11 Applicable Legislation MDDEP s Soil Protection and Contaminated Sites Rehabilitation Policy Soils: Commercial properties: level C of the generic criteria Residential properties: level B of the generic criteria Groundwater: Criteria of the seepage into the surface water or infiltration into sewers

12 Regulations - Quebec vs Alberta

13 Site Description Applicable Legislation Site Environmental Background Challenges Remediation Technologies Results Conclusions Questions

14 Site Environmental Background Six characterization studies 60 monitoring wells 10 contaminated sites

15 Site Environmental Background Geology / hydrogeology: Groundwater flow direction Restaurant Former gas station Restaurant Hydrogeological characteristics House 1 Rue 1 Geological characteristics Different horizons Fine sand with clay layers Silt Fine sand to medium sand House 2 House 3 House 4 Velocity= 6m/year K = 10-3 cm/s Depth = 5,5 to 6,5 m Bank Rue 2 House 5 House 6

16 Site Environmental Background Restaurant Former gas PHC 10 C 50,, BTEX, PAHstation Presumed extent of contaminated soils Residential criteria House 1 Street 1 Presumed extent of contaminated soil Commercial criteria BTEX Restaurant House 2 House 3 BTEX House 4 Soil concentrations below applicable criteria Soil concentrations exceeding residential criteria Soil concentrations exceeding commercial criteria Bank House 5 House 6 Street 2

17 Site Environmental Background Restaurant Former gas station House 1 Street 1 Presumed extent of contaminated groundwater Presumed extent of free phase product Restaurant House 2 House 3 House 4 Groundwater concentrations below applicable criteria Groundwater concentrations exceeding applicable criteria Bank House 5 House 6 Street 2

18 Site Environmental Background Former gas station and restaurant House 1 Restaurant Street 1 House 2 House 3 House 4 Bank House 5 House 6 Street 2

19 Site Environmental Background Commercial sites Former gas station and Restaurant Old gas station 4,0 m Contaminated soils Sols contaminés Produit Product en phase libre 7,0 m Sols Contaminated contaminés soils Groundwater Contaminated groundwater

20 Site Environmental Background Restaurant Former gas station Restaurant and street House 1 Street 1 House 2 House 3 House 4 Bank House 5 House 6 Street 2

21 Site Environmental Background Commercial sites Restaurant and street 5,5 m 6 m Contaminated soils Product 7,0 m Contaminated soils Contaminated groundwater

22 Site Environmental Background Restaurant Former gas station Restaurant House 1 Rue 1 House 2 House 3 House 4 Houses Bank House 5 House 6 Rue 2

23 Site Environmental Background Residential properties 5,50-7,5 m Characteristics: Low BTEX concentrations in soils High BTEX concentrations in groundwater 6 m Contaminated soils and groundwater 10 m

24 Site Description Applicable Legislation Site Environmental Background Challenges Remediation Technologies Results Conclusions Questions

25 Challenges 10 contaminated sites Presence of commercial activities Buildings, private houses, landscaping Many stakeholders including: residents, business owners, municipality Sites located on busy streets Environmental problematic differed from one site to another

26 Challenges

27 Site Description Applicable Legislation Site Environmental Background Challenges Remediation Technologies Results Conclusions Questions

28 Remediation Technologies Restaurant Pumping test Former gas station Pumping Restaurant test House 1 Street 1 House 2 House 3 House 4 Bank Chemical Oxidation test House 5 House 6 Street 2

29 Remediation Technologies Pumping test: Realized on two sites at different season Pumping of groundwater and air from the geological formation from a given observation well and monitoring the influence to determine: Radius of influence Viability of the technology under field conditions Type and size of equipments Quantity of the extraction and the injection wells Quantity of the pumping wells if necessary

30 Remediation Technologies Pumping test (Suite): Results: Large influence of radius Easy to lower the groundwater Coherent test results (both tests) Excellent field conditions for applying technologies: Multi-Phase Extraction Pump and treat Sparging

31 Remediation Technologies Chemical Oxidation test: Proposed technology to be used for residential sites: Contaminated soils located in the saturated zone Possibility to remediate the soils and the water in the same time Good field conditions for technology Injection of an oxidant (sodium persulfate) and a catalyst (chelated iron or caustic soda ) in the soil to determine: Natural oxydant demand (NOD) Radius of influence Viability of technology under field conditions Quantity of the injection points

32 Remediation Technologies Chemical Oxidation test (Suite): Results: Good influence of radius Good product repartition Easy to inject the product (low pressure injection) Technology not selected for reasons of cost

33 Remediation Technologies Restaurant Former gas station Multi-Phase Extraction Soils between 4 and 7 mbgs contaminated by BTEX House 1 Excavation and on site biopile Soils between 0 to 4 mbgs contaminated by PHC 10 C 50 and PAHs Restaurant Rue 1 House 2 House 3 House 4 Bank Pump and treat, sparging and biological treatment Soils between 6 to 10 mbgs contaminated by BTEX Rue 2 House 5 House 6

34 Remediation Technologies On site Biopile Restaurant On site biopile Former gas station House 1 Excavation and on site biopile Soils between 0 to 4 mbgs contaminated by PHC 10 C 50 and PAHs Restaurant Rue 1 House 2 House 3 House 4 Bank House 5 House 6 Rue 2

35 Remediation Technologies On site Biopile Located to the south and southwest of the former gas station Soil between 0 and 4 mbgs Advantages: Presence of PAH contamination biologically treatable Underground Biopile: reduce odours and visual impact for neighbours Treatment parameters easy to control Less expensive than dig and dump, even more in remote sites Disadvantages: Dust emission during implementation Presence of machineries in a residential area Requires demolition of existing structures

36 Remediation Technologies On site Biopile Air COV toward treatment unit Extraction pipe Geomembrane Natural soils Contaminated soils Natural soils Geomembrane and geotextile Contaminated soils Extraction pipe Natural soils Geomembrane and geotextile

37 Remediation Technologies On site Biopile

38 Remediation Technologies Multi-Phase Extraction Restaurant Former gas station Multi-Phase Extraction Soils between 4 and 7 mbgs contaminated by BTEX House 1 Restaurant Rue 1 House 2 House 3 House 4 Bank House 5 House 6 Rue 2

39 Remediation Technologies Multi-Phase Extraction Commercial Area Advantages: Allow treatment of impacted soils at depth Provide possibility of lowering the water table Less impact on neighbours No structure support required Technology easily applicable to light hydrocarbon Disadvantages: Treatment parameters harder to control

40 Remediation Technologies Multi-Phase Extraction Commercial sites Fuel Treated air Unit Clean air Contaminated water and air Product Treated water Municipal sewer Product recovery Product Contaminated soil Groundwater

41 Remediation Technologies Multi-Phase Extraction Commercial sites Fuel Treated air Unit Clean air Contaminated air Treated water Municipal sewer Remediation of contaminated soil Contaminated soils Groundwater

42 Remediation Technologies Multi-Phase Extraction Two treatment units installed to remediate three commercial properties and one street Treatment units connected to 68 extraction and 78 injection wells Four pumping wells installed for lower the groundwater level

43 Remediation Technologies Multi-Phase Extraction

44 Remediation Technologies Pump and Treat / Sparging Residential properties Three combined technologies: Pump and treat Sparging Biologic treatment Versatile technology allows : To remediate in depth contaminated soils To remediate contaminated soils in both vadose and saturated layers To adjust the operation conditions of the system to the groundwater level

45 Remediation Technologies Pump and Treat / Sparging Residential properties Treated air Unit Treated water Municipal sewer Contaminated water Clean air Contaminated water Contaminated soils and groundwater Extraction well Injection well

46 Remediation Technologies Pump and Treat / Sparging Residential properties Treated air Unit Treated water Municipal sewer Contaminated air and water Clean air Contaminated air and water Contaminated soils and groundwater Water Extraction well Air injection well

47 Remediation technologies Pump and Treat / Sparging One treatment unit connected to 16 extraction and 7 injection wells Underground piping installed with a torpedo to minimize the impacts on the properties Two pumping stations

48 Remediation Technologies Pump and Treat / Sparging Torpedo Torpedo tip

49 Site Description Applicable Legislation Site Environmental Background Challenges Remediation Technologies Results Conclusions Questions

50 Results Restaurant Former gas station Commercial sites More that 95 % of the soils comply with the applicable criteria Free phase product is recovered BTEX are not detected in groundwater So far: 35 tons of gas recovered m 3 of water 18 millions m 3 of air 3 years of treatment Restaurant House 1 Bank Rue 1 Residential properties System installed Treatment will begin in 2012 House 2 House 3 Rue 2 House 4 House 5 House 6

51 Site Description Applicable Legislation Site Environmental Background Challenges Remediation Technologies Results Conclusions Questions

52 Conclusions Monitoring wells installation Communications with landowners

53 Questions???

54 Thank you for your attention