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WE MAKE THE LANDFILL TRANSPARENT
Development of a step by step geo-electrical methodology for landfill investigation
Håkan Rosqvist, Rosqvist Resurs
Torleif Dahlin and Virginie Leroux, Lund University,Mats Svensson, Sara Johansson, Carl-Henrik Månsson Magnus Lindsjö, Tyréns, Sweden
Workshop Malmö 16–17 February 2012
MaLaGa
Objective
To summarize the outcome of several years of research and development in geo-electrical measurements, and to develop a methodology for landfill investigations.
Time and cost effective methodology
MaLaGa
The step by step methodology is based on
1. Electromagnetic conductivity meter – CMD (Stångslingram)
2. Resistivity – Large scale 3. Resistivity – small scale
Measurements in 2010 and 2011 at Filborna landfill site, Helsingborg, Sweden.
Background map – Filborna landfill
A - Final soil cover
B – Old road partly filled with inert waste
C – Intermediate soil cover
• 1950 – 2008• Depth – 40-45 m• Area – 35 Ha• 11 Mton of waste
Electromagnetic conductivity meter - CMD 4/6
CMD 4
CMD 6
Large scale resistivity
2D set-up for measurements in 11 lines
The ABEM Lund Imaging System (Dahlin, 1996)
Large scale measurements - Large scale features
Bedrock
Erosion valley (old river)
High resistivity near surface
Parts with low resistivity in the landfill at depths
Fence diagram
3D Resistivity Mapping
3D Resistivity Mapping
3D IP Mapping
• ABEM Terrameter LS• 3 x ABEM Electrode Selector
ES10-64C• Lightning protection• Mobile internet modem / router• PC for fast data transfer / back-up • Mains power supply
• Stainless steel rod or plate electrodes
• Electrode cables w. pig-tail take-outs
• Water-protected connections
Small scale data acquisition system – 3D
Monitoring Layout Filborna 2011
Small scale
Area for measurements – 22 by 40 meter
Homogeneous resistivity distribution
Small variations over time
Resistivity distribution
Small scale – 3D
Background information
Various historical geo-information
Old photos
Organic waste
Wall – waste/clay
Soil cover
Saturated
Unsaturated
Area with old ”biocells” – some features
Aftonbladet 3 juli 2011
Köpenhamn lamslogs av åskovädret
Jättehagel, kaskadregn och tusentals blixtnedslag. Köpenhamn lamslogs när vädrets makter tog över staden.
Sent i natt hade DMI räknat till 5 309 blixtnedslag och 150 millimeter regn i Köpenhamn med omnejd, enligt danska tidningar.
BILDEXTRA Kaos efter åskoväder Strömavbrott och översvämningar
July 2 - Thunderstorm
Water infiltration after heavy rainfall
Decrease in resistivityIsosurface showing a -6% change
6 hours between measurements
Zone with water infiltration correlated to the wall?
Water infiltration after heavy rainfall
Zone with variability in resistivity
Next step
Validation of the results from the geo-electrical measurements by field sampling and other physical investigations.
