Reclamation of Contaminated Soil After Solidification/Stabilization Treatment

Transcription

1 Reclamation of Contaminated Soil After Solidification/Stabilization Treatment Example of port pavement optimization in the Viau Sector of the Port of Montreal JEAN-PHILIPPE BOUDREAULT, ENG. JEAN-SÉBASTIEN DUBÉ, ENG., PH.D. HUGO BRASSARD, ENG. ÉCOLE DE TECHNOLOGIE SUPÉRIEURE ÉCOLE DE TECHNOLOGIE SUPÉRIEURE MONTREAL PORT AUTHORITY

2 PRESENTATION OUTLINE PART I: Introduction to solidification/stabilization (S/S) treatment PART II: Project carried out in the Viau Sector of the Port of Montreal PART III: Optimization of pavement design by value-added integration of S/S treatment CONCLUSIONS

3 PART I: INTRODUCTION TO SOLIDIFICATION/STABILIZATION TREATMENT

4 INTRODUCTION TO S/S TREATMENT S/S TREATMENT Consists of incorporating a binding reagent (e.g. cement), water and additives into the contaminated material to render it environmentally safe (immobilization of contaminants) DOUBLE ENVIRONMENTAL PROTECTION Stabilization: chemical changes that reduce the solubility of contaminants Solidification: physical changes leading to encapsulation of the soil in a cement matrix, reduction of its hydraulic conductivity and an increase in its strength 4

5 INTRODUCTION TO S/S TREATMENT S/S TREATMENT HAS BEEN USED FOR OVER 50 YEARS 1950s for treatment of radioactive waste; 1970s for treatment of hazardous waste. S/S TREATMENT IS PROVEN FOR SEVERAL TYPES OF MATRICES Soils, sediments, sludge, residual materials. S/S IS APPLIED IN MANY COUNTRIES Canada, United States, Europe (France, United Kingdom, Netherlands, etc.) S/S TREATMENT IS DEMONSTRATED FOR SEVERAL TYPES OF CONTAMINANTS Metal contamination (main use); Polycyclic aromatic hydrocarbons (PAHs); Persistent organics: polychlorinated biphenyls (PCBs), dioxins and furans; Tar, refinery residues, etc. 5

6 INTRODUCTION TO S/S TREATMENT SUPERFUND U.S. From 1982 to 2008: 22% of the treatment projects completed resorted to solidification/stabilization Source: USEPA, 2010 Rated by the U.S. Environmental Protection Agency (USEPA) as Best Demonstrated Available Technology for inorganic contamination 6

7 S/S TREATMENT: IN SITU PROCESS 7

8 S/S TREATMENT: EX SITU PROCESS 8

9 INTRODUCTION TO S/S TREATMENT Phased treatment process Site characterization Treatability study Laboratory In situ pilot test Full-scale treatment 9

10 INTRODUCTION TO S/S TREATMENT Quality control program Physical tests Chemical tests Compression strength Total extractable concentrations Tensile strength Static leaching (TCLP, SPLP, water) Durability (freeze/thaw or wetting/ drying cycle) Hydraulic conductivity Relative compaction Density and water content Dynamic leaching (diffusivity) Solubility of contaminants Acidity neutralization capacity Mineralogical analyses Absorption and particle density Granulometric analysis 10

11 PART II: PROJECT CARRIED OUT IN THE VIAU SECTOR OF THE PORT OF MONTREAL 11

12 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL Project context Need: - Increase container storage capacity in the Port of Montreal to support the growing demand Objective: - Requalify the Viau Sector as a container storage sector with a capacity of 150,000 TEU (twenty-foot equivalent units) Work: - Overall project of $30.6 million - Area of around 90,000 m 2 - Project divided into three phases 12

13 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL Summary of the work PHASE 1: Soil consolidation Demolitions of existing buildings and infrastructure Reconstruction of main infrastructure (power grid and mains) Surface compaction for the zone above the caissons Dynamic compaction 13

14 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL Summary of the work PHASE 2: Relocation of the railway tracks Construction of new marshalling yard for the grain terminal Construction of a new link with the existing railway system 14

15 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL Summary of the work PHASE 3: Site development Construction of underground infrastructure: storm sewer, aqueduct, power grid Construction of the new pavement structure Construction of driving surfaces and manoeuvring areas Development of new LED lighting towers 15

16 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL Problem PAVEMENT THICKNESS Very high costs for construction of the new port pavement - Costs related to soil excavation - Costs related to burial of contaminated soil - Costs related to importing of a considerable quantity of granular materials PROPOSED SOLUTION: Reuse of contaminated soil as a subbase material following solidification/ stabilization (S/S) treatment 16

17 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL S/S treatment of contaminated soil Stage 1: Construction of a reserve pile of contaminated soil 17

18 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL S/S treatment of contaminated soil Stage 2: Mixing in a mobile pugmill 18

19 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL S/S treatment of contaminated soil Stage 3: Transport and placement of treated soil 19

20 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL S/S treatment of contaminated soil Stage 4: Compaction and wet curing of treated soil 20

21 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL S/S treatment of contaminated soil Stage 5: Quality control (core sampling and production of specimens) 21

22 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL S/S treatment of contaminated soil General views of the site (S/S work in progress) S/S monolith recovered during curing S/S monolith exposed after curing 22

23 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL S/S treatment of contaminated soil Large-scale S/S treatment DURATION OF S/S TREATMENT: 3 weeks (day and night) TOTAL VOLUME OF S/S MONOLITHIC MASS: 19,000 m 3 (area of about 65,000 m 2 ) PERFORMANCE TESTS: 44 test series (~1 series/500 m 3 ) and additional core sampling on site QUANTITY OF TREATED SOIL 35,000 m.t. of contaminated soil subjected to S/S treatment 23

24 REDEVELOPMENT OF THE VIAU SECTOR, PORT OF MONTREAL S/S treatment of contaminated soil Performance criteria specific to the project TEST PROJECT CRITERION MDDEFP CRITERION PHYSICAL TESTS Tensile strength (at 28 days) > 1.8 MPa - Compression strength (at 28 days) > 3.5 MPa > 3.5 MPa Hydraulic conductivity < 10-7 cm/s < 10-7 cm/s Physical alteration CHEMICAL TESTS < 10% loss of material at 21 cycles (freeze/thaw) < 10% loss of material at 12 cycles (optional) SPLP leaching < potability criteria < potability criteria Water leaching < potability criteria < potability criteria Diffusivity (leachability index) > 9 > 9 24

25 PART III: OPTIMIZATION OF PAVEMENT DESIGN BY VALUE-ADDED INTEGRATION OF S/S TREATMENT Taken from the presentation made at the 49 th Annual Congress of the Association québécoise des transports (Boudreault et al, 2014) 25

26 EXAMPLE OF PAVEMENT OPTIMIZATION Redevelopment of the Viau Sector of the Port of Montreal Traffic loads Number of trips projected for the new port pavement - Rubber-tired gantry crane: 200,000 trips over 20 years - Front-end loader: 80,000 trips over 20 years - Tractor-trailer: 3,000,000 trips over 20 years RUBBER-TIRED GANTRY CRANE FRONT-END LOADER TRACTOR-TRAILER 26

27 EXAMPLE OF PAVEMENT OPTIMIZATION Redevelopment of the Viau Sector of the Port of Montreal Overall structure (container storage and handling) Preliminary design (975 mm thickness) Optimized design (810 mm thickness) 225 mm Asphalt pavement 210 mm Asphalt pavement 300 mm 450 mm Granular material MG20 Granular material MG mm 300 mm 300 mm Granular material MG20 S/S Monolith 810 mm Subgrade Water table 27

28 EXAMPLE OF PAVEMENT OPTIMIZATION Redevelopment of the Viau Sector of the Port of Montreal Structural analysis of the pavement Comparison of the overall pavement structures Preliminary design (975 mm) Optimized design with S/S (810 mm) Optimized design with S/S (810 mm) and degradation LOAD Number of admissible trips Number of admissible trips Number of admissible trips Rubber-tired gantry crane Front-end loader Tractor-trailer x 161 % x 168 % x 104 % Number of admissible trips = Pavement durability 28 Boudreault et al. Atelier national sur les infrastructures maritimes, 3 février 2016

29 EXAMPLE OF PAVEMENT OPTIMIZATION Redevelopment of the Viau Sector of the Port of Montreal Modelling of stresses transmitted to the S/S monolith Optimized design with S/S (810 mm) LOAD Stress at the base of the S/S monolith Rubber-tired gantry crane Front-end loader Tractor-trailer 0,7 MPa 0,9 MPa 0,2 MPa Serves to establish a physical perfomance criterion 29 Boudreault et al. Atelier national sur les infrastructures maritimes, 3 février 2016

30 EXAMPLE OF PAVEMENT OPTIMIZATION Redevelopment of the Viau Sector of the Port of Montreal Drainage system of the pavement Asphalt pavement Opening in the S/S monolith at the lowest points Granular material MG20 S/S Monolith Water flow Perforated drain connected to the manhole 30 Boudreault et al. Atelier national sur les infrastructures maritimes, 3 février 2016

31 S/S TREATMENT MAKES IT POSSIBLE TO REALIZE: - CONSIDERABLE SAVINGS ON AN ENTIRE PROJECT - Estimated at approximately $2.1 million by the Port of Montreal (over a project phase of approximately $5 million) for redevelopment of the Viau Sector - CONSTRUCTION OF A DURABLE PAVEMENT - Increase in the structural strength of the foundation of the port pavement compared to a conventional pavement - Increase in the pavement s lifespan (increased number of admissible trips) - SUSTAINABLE MANAGEMENT OF CONTAMINATED SOIL - Safe on site reclamation of contaminated soil - Long-term control of the risks of migration of contamination - Reduction of transport and off site burial of contaminated soil - Minimization of importing of clean (and/or granular) materials for backfilling - Reduction of transport-related greenhouse gas (GHG) emissions 31

32 THANK YOU! JEAN-PHILIPPE BOUDREAULT, ENG.