Electromagnetics for the

Investigation of Landfills: Three

(Short) Case Studies from the

Valley of Mexico

Matthias Bücker

University of Bonn (Germany) and

TU-Wien (Austria)

2017 DISC lab | Mexico City

Study sites in the Valley of Mexico

1. Tepexpan

- DC resistivity and TDEM

- Conductive waste in resistive volcanic rock

2. New International Airport

- DC resistivity and TDEM

- Conductive waste over saline clay

3. Prados de la Montaña

- Spectral induced polarization

- Conductive, chargeable waste

Background map: INEGI

1. Tepexpan (State of Mexico)

1. Tepexpan

Setup

- Abandoned landfill in pyroclastic rock (tuff,

scoria) and basalts

Properties

- Conductive waste (< 20 Ωm)

- Resistive host rock (> 100 Ωm)

(Actual) Objective

- Assess geometry of scoria and basalt

units for mining purposes

1. Tepexpan (State of Mexico)

TEP19TEP20

Landfill

BasaltTuff/

Scoria

TuffTuff

Tuff (toba)

Scoria (tezontle)

Tuff

TDEM: TEP20

Landfill

Tuff/

Scoria

Tuff

TDEM: TEP19

Tuff

Basalt/

Scoria

WE

DCR: Line TP3

Geological setting

Landfill

Survey

- DCR (10 m spacing, ~ 1 km line length)

- TDEM (50 m x 50 m loop)

Processing

- DCR: 2D inversion (EarthImager)

- TDEM: 1D inversion (WinGLink)

Summary

- Identified abandoned landfill and possible leachate

plume by low resistivity values from DCR and TDEM.

Pit

Leachate

plume?

2. New International Airport (State of Mexico)

2. New International Airport

Setup

- Abandoned landfill on top saline clay (former lake Texcoco)

Properties

- Conductive waste (~ 1 Ωm)

- Even more conductive clay (<< 1 Ωm)

Objective

- Estimate thickness (and volume) of waste deposits

N

0+000

1+4001+400

0+000

0+470

0+000

0+470

0+000

0+470

0+000

0+470

0+000

0+705

0+000

0+000

0+2000+000

0+000

0+000

0+000

0+200

0+200

0+200

0+200

0+000

0+000

0+000

1+000

1+000

1+000

Profile

6

0.20.2 0.2 0.2 0.2 0.2

0.810.94 0.88 0.87 0.95 0.95

1.21.01 1.19

0.94 0.94 0.96

NAICM landfill | Profile 6

TDEM 0+385 m

0.95

Ωm

0.2

Ωm

0.96

Ωm

0+

33

5 m

0+

34

5 m

0+

35

5 m

0+

36

5 m

0+

37

5 m

0+

38

5 m

Debris

Saline clay

NS

Survey

- DCR (Ares, 3 m spacing)

- TDEM (TerraTEM, single loop, 10 m x 10

m loop)

Processing

- DCR: 2D inversion (Res2DInv)

- TDEM: 1D (WinGLink)

Summary

- Identified waste/debris layer by

(relatively high resistivity)

- Excellent agreement of DCR and TDEM

(three-layer inversion) results

N

0+000

1+4001+400

0+000

0+470

0+000

0+470

0+000

0+470

0+000

0+470

0+000

0+705

0+000

0+000

0+2000+000

0+000

0+000

0+000

0+200

0+200

0+200

0+200

0+000

0+000

0+000

1+000

1+000

1+000

NAICM landfill | Profil 13

Línea 13

L13-500

L13-750

0+

62

0 m

0+

67

0 m

0+

71

0 m

WE

0+

63

0 m

0+

64

0 m

0+

65

0 m

0+

66

0 m

0+

68

0 m

0+

69

0 m

0+

70

0 m

0+

72

0 m

0+

730 m

0+

74

0 m

0+

75

0 m

0+

76

0 m

0+

77

0 m

0+

78

0 m

0+

79

0 m

0+

80

0 m

0+

81

0 m

0+

82

0 m

1.9 2.15 1.74 1.95 1.91.09

1.01.22 1.27 1.01 1.1

0.20.230.20.2channel

3. Prados de la Montaña, Mexico City

3. Prados de la Montaña landfill

Setup

- Closed landfill in volcanic rocks (tuff, pyroclastic

sediments)

Properties

- Conductive (<< 10 Ωm) and chargeable (up to 50

mrad) waste

- More resistive (>> 100 Ωm) and non-chargeable

host rock

Objective

- Determine geometry of waste deposits

3. Prados de la Montaña

Electrodes

IP5 outside

of landfill

Lower limit

of the

landfill

Survey

- DCR (Syscal Pro Switch, Dipole-

dipole, 6-7 m spacing, 48 electrodes)

Processing

- DCR: 2D inversion (CRTomo)

Summary DCR

- Waste only conductive, where

saturated with leachate?

- Leachate plume beneath actual

landfill?

3. Prados de la Montaña

1 Hz

2 Hz

4 Hz

8 Hz

0.5 Hz

Survey

- SIP (GDP32ii, Dipole-dipole,

8 m spacing, 30 electrodes)

Processing

- SIP: 2D inversion (CRTomo

by Andreas Kemna, Bonn)

Summary SIP

- Phase correlates better with known geometrical limits of landfill

- Lateral heterogeneities might give a hint to waste composition

- Open question: What information does the spectral variation contain?

(-> composition, saturation, fluid chemistry, particle sizes)?

Thanks to…

~ 1750 Dumpsites located in

Santa María la Ribera

Historic dumpsite (DF)

Historic dumsite (EdoMex)

19th century

20th century (1st half)

1924 Santa Cruz Meyehualco

1938 Dumpsites at the

Monumento a la Raza and in

Tacubaya, Dos Ríos,

Magdalena Mixhuca

Monumento a la Raza

Tacubaya

Dos RiosSanta Cruz Meyehualco

Magdalena Mixhuca

Historic dumpsite (DF)

Historic dumsite (EdoMex)

1958 Santa Fe

1983 Closure of Santa Cruz

Meyehualco causes the

opening of dumpsites San

Lorenzo Tezonco, Tlalpan,

Milpa Alta, Cerro de la Estrella,

Tarango,, Santa Catarina,

Bordo de Xochiaca, Tlahuác,

San Mateo Nopala,

Cuautepec.

1985 Bordo Poniente

1985-87 Santa Catarina,

Prados de la Montaña

Santa Cruz MeyehualcoSanta Fe

Tlalpan

Milpa Alta

San Lorenzo

Tezonco

Cerro de

la Estrella

Santa Catarina

Bordo Poniente

Prados de

la Montaña

Tarango

San Mateo

Nopala

Cuautepec

Tlahuác

20th century (2nd half)

Historic dumpsite (DF)

Historic dumsite (EdoMex)

References

Historic development of dumsites in Mexico City

Deffis Caso, Armando, 1994. La basura es la solución. 1ra Edición,

México D.F., Editorial Árbol

Jiménez, Blanca Elena, 2001. La contaminación ambiental en

México: Causas, efectos y tecnología apropiada. Colegio de

ingenieros ambientales de México, A.C. Instituto de Ingeniería

de la UNAM y FEMISCA, México, Editorial Limusa

Mora Reyes, J. A., 2004. El problema de la basura en la Ciudad de

México. Fundación de estudios urbanos y metropolitanos.