How can geophysical methods help to characterize landfills? Focus on Onoz landfill David Caterina , Itzel Isunza Manrique , Frédéric Nguyen 1 RAWFILL
Agenda of the presentation • A short introduction to geophysics • Landfill investigation • Context • Extension • Composition • Landfill monitoring • Take home message • Landfill of Onoz 2 RAWFILL
Agenda of the presentation • A short introduction to geophysics • Landfill investigation • Context • Extension • Composition • Landfill monitoring • Take home message • Landfill of Onoz 3 RAWFILL
A short introduction to geophysics: Objectives Mapping spatial variations in: Monitoring changes in: • Lithology/waste type/density • Waste/contaminant mass • Water content • Tracer concentration • Pore fluid or total dissolved solids • Amendement injection • Mechanical properties • Compaction/density/porosity • Metallic content • Gas production Translate the geophysical variations or changes into property of interestassuming a relationship. 4 RAWFILL
Why geophysics? 5 RAWFILL
Example: contaminant detection 6 6 RAWFILL
Classical approach 7 RAWFILL
Classical approach 8 RAWFILL
Classical approach 9 RAWFILL
Classical approach 10 RAWFILL
Classical approach Accurate but low-density spatial and temporal information 11
With geophysics … ( here ERT) Suspect zone 12 RAWFILL
Focus on the geophysical anomaly 13 RAWFILL
Pro ro and and co cons • Non to minimally invasive • Indirect information • Relatively low cost • Resolution decreases with depth • Large coverage • Prone to modeling errors • See through technology (artefacts) 14
Different methods... Seismics EM ERT/IP Magnetic 15
Different targets… Method Bulk (geo)physical property Relevant information Acquisition/(ex. of main limitations) Seismics (refraction, surface Elastic moduli, density Structures, faults, depth to bedrock, Surface, borehole, cross-hole/(velocity waves, reflection, ambient noise) (seismic velocities) lithology inversion, ambient vibrations) DC electrical resistivity Electrical resistivity Water content, salinity, pore fluid, Borehole, cross-hole, surface/(impermeable temperature, porosity, lithology membrane) A combination of different Induced polarization (IP) Chargeability Disseminated metallic particles (pyrite), Borehole, cross-hole, surface (noise and clay, surface area, lithology inductive coupling) methods is recommended Spontaneous potential (SP) Electrical charges and Flow in porous media, redox potential Borehole, cross-hole, surface/(electrical electrical conductivity noise) to reduce uncertainties Ground Penetrating Radar (GPR) Dielectrical constant and Structures, faults, water content, salinity, Borehole, cross-hole, surface/(conductive electrical conductivity pore fluid, porosity, lithology ground) Electromagnetic (EM) Electrical conductivity and Water content, salinity, pore fluid, Borehole, cross-hole, surface, airborne or magnetic susceptibility porosity, lithology, Ferrous materials ATV mounted/(Metallic external objects) Magnetic Magnetic susceptibility Ferrous materials (buried drums, Surface/(Metallic external objects) containers…), lithology Gravimetry Density Voids, basin-like structures Surface/(corrections, measurement time) Borehole logging (caliper, gamma, Many Many: fracture locations, clay content, Borehole 16 sonic, flowmeter, TV) lithology, transmissivity, …
The main phases of a geophysical investigation and associated costs • Pre-investigation and • Desk study feasibililty • Equipment preparation and • Set-up • Properties depreciation • Surveys • Field study • Measurements on site • Data quality control • Transport to and on site • Possible interferences • Data acquisition • Data processing and • Accomodation interpretation • Desk study • Image appraisal • Complementary data • Report synthesis 17 RAWFILL
A lot of pragmatism too: site access, logistics, near-surface objects (cables etc…) 18 RAWFILL
Agenda of the presentation • A short introduction to geophysics • Landfill investigation • Context • Extension • Composition • Landfill monitoring • Take home message • Landfill of Onoz 19 RAWFILL
Applied geophysics and landfills Book chapter by Soupios and Ntarlagiannis (2017) Dedicated development (e.g. Audebert et al., 2014; Query performed 03/02/2018: (TITLE-ABS-KEY(landfill* AND geophysic*)) Konstantaki et al., 2016; Dumont et al., 2016; van de Scopus # with landfill* AND geophysic* Vijver 2017) 600 Clément et al., 2010 Monitoring 500 Grellier et al., 2007, Focus on DC resistivity 400 De Laco et al., 2003 300 Multi-scale Green et al., 1999 200 Multi-method Whitley and Jewel, 1992 100 Feasibility 0 1960 1970 1980 1990 2000 2010 2020 20
Europe leads the way! Scopus # per geographical area 200 180 160 140 120 100 80 60 40 20 0 21 RAWFILL
Physical properties of wastes: solid part Dumont (2017) 22 RAWFILL
Physical properties of wastes: liquid part 23 RAWFILL
Physical properties of wastes: liquid part 24 RAWFILL
Physical properties of wastes Generally, geophysical properties contrast well with the surrounding environment • Leachate ionic strength and temperature increase > low electrical resistivity (0.5-30 m) • Metal scraps and redox reactions > high chargeability and self- potential (100s mV/V, 100s mV) • Ferromagnetic objects > 2-4 orders of magnitude larger than sedimentary rocks • Low compaction > lower density 1-2 t/m 3 and lower elastic moduli (Vp~180 m/s to 1450m/s) 25 RAWFILL
Agenda of the presentation • A short introduction to geophysics • Landfill investigation • Context • Extension • Composition • Landfill monitoring • Take home message • Landfill of Onoz 26 RAWFILL
Landfill investigation: extension Average driving speed 7.3 km/h loamy sandy soil Van de Vijver PhD, 2017 background 27 RAWFILL
Agenda of the presentation • A short introduction to geophysics • Landfill investigation • Context • Extension • Composition • Landfill monitoring • Take home message • Landfill of Onoz 28 RAWFILL
Landfill investigation: Composition Towards quantitatvie spatial distribution of leachate property : petrophysics ρ b = 1.53 ∗ 0,40 ∗ θ 𝑤 −2.101 σ 𝑈 = 0.19 T − 25 + 1 σ 25 (Dumont et al., 2016) 29 RAWFILL
Landfill investigation: Composition • Towards quantitative spatial distribution of leachate property ρ b = 1.53 ∗ 0,40 ∗ θ 𝑤 −2.101 σ 𝑈 = 0.19 T − 25 + 1 σ 25 (Dumont et al., 2016) 30 RAWFILL
Agenda of the presentation • A short introduction to geophysics • Landfill investigation • Context • Extension • Composition • Landfill monitoring • Take home message • Landfill of Onoz 31 RAWFILL
Landfill monitoring Les Champs-Jouault experimental site Injection trench Household waste, non-hazardous • industrial waste (Audebert et al., 2014) 32 RAWFILL
Landfill monitoring (Audebert et al., 2014; 2016) 33 RAWFILL
Agenda of the presentation • A short introduction to geophysics • Landfill investigation • Context • Extension • Composition • Landfill monitoring • Take home message • Landfill of Onoz 34 RAWFILL
Take home message • Not a silver bullet (no universal response), it needs to be assisted by complementary data • Go/No go pre-feasibility using pre-modeling should be standard procedure On landfills : • Landfills Hor./Vert. delimitation is demonstrated > multi-methods very efficient • For composition quantification: requires careful and dedicated processing and laboratory petrophysics • Geophysical monitoring can follow leachate injection, membrane leaking • To follow biodegradation is more challenging in the long term 35 RAWFILL
Agenda of the presentation • A short introduction to geophysics • Landfill investigation • Context • Extension • Composition • Landfill monitoring • Take home message • Landfill of Onoz 36 RAWFILL
Site overview History: 1902-1967: Quarry, limestone • extraction • 1967-1976: Deposit ashes & 1971 1976 lime 1982-1987: waste from • construction sector, tyres, rubber... 2004: 750t of tires removed by • SPAQuE 2000 2009 RAWFILL 37
Today … RAWFILL 38
Site description Site elevation - 20 m of ashes in the upper part - 4-? m of waste + lime in the bottom part RAWFILL 39
Goal of the first survey: 1. Estimate extension and boundaries of the waste 2. Identify ashes and lime 3. Leachate? RAWFILL 40
Methods – Survey design Mapping methods: Electromagnetic survey (EM) • Profiling methods ERT/ IP • RAWFILL 41
Fieldwork done - covering EM survey ERT/ IP RAWFILL 42
Results EM Conductivity RAWFILL
Results ERT/IP P1 S N P2 P1 RAWFILL 44
Results ERT/IP P2 S N P2 P1 RAWFILL
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