COMUNICAÇÃO TÉCNICA ______________________________________________________________________________________________________________________________________________________________________________________________________

Nº 174753

High resolution techniques for geoenvironmental characterization of a site with methane in the subsoil Leandro Gomes de Freitas Marco Aurélio Zequim Pede Chang Hung Kiang

Trabalho apresentado no INTERNATIONAL CONTAMINATED SITE REMEDIATION CONFERENCE, CLEAN UP, 7th., 2017,

Melbourne. Proceedings...

A série “Comunicação Técnica” compreende trabalhos elaborados por técnicos do IPT, apresentados em eventos, publicados em revistas especializadas ou quando seu conteúdo apresentar relevância pública. ___________________________________________________________________________________________________

Instituto de Pesquisas Tecnológicas do Estado de São Paulo S/A - IPT

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São Paulo | SP | Brasil | CEP 05508-901 Tel 11 3767 4374/4000 | Fax 11 3767-4099

www.ipt.br

HIGH RESOLUTION TECHNIQUES FOR GEOENVIRONMENTAL CHARACTERIZATION OF A SITE

WITH METHANE IN THE SUBSOIL

Leandro Gomes de Freitas1, Marco Aurélio Z. Pede2, Chang Hung Kiang2

1Geoenvironmental Technologies Center - CTGeo, Institute for Technological Research – IPT,São Paulo, BRAZIL

2Laboratory of Watershed Studies - LEBAC, Institute of Geosciences and Exact Sciences, São Paulo State University – UNESP, Rio Claro, BRAZIL

Introduction

Contaminated sites: risks associated with gas and vapour intrusionsin buildings.

Source: adapted from ITRC (2009).

CH4 contaminated sites: social, political and economic concerns

Center Norte Shopping Mall Cingapura Housing USP Leste University

Source: G1.globo.com (10/10/11)Source: G1.globo.com (28/09/11) Source: Folhapress (17/11/11)

How to obtain better site diagnostics?

High Resolution Site Characterization (HRSC)

Source: USEPA (2011)

HRSC: Membrane Interface Probe (MIP)

Source: Geoprobe (2012)

Objective

Evaluate the application of the MIP with otherauxiliary techniques for site characterization withmethane occurrence in the subsoil.

Study Area: USP - Este Campus

Source: http://www.usp.br/imprensa/?p=9604

Study Area: USP - Este Campus

I1

E2

Study area

USP LESTE

SÃO PAULO MUNICIPALITY

Study Area: USP - Este Campus

Methodology

Three stages, including laboratory and fieldprocedures;

• 1st Stage: Bench testsFoto 9: Preparação das misturas gasosa. Foto 10: Injeção das misturas gasosas

na sonda MIP.

Preparation and injection of the gaseous mixtures in the MIP system

1st Stage: Bench tests

FID detector response graphs

2nd Stage: Field tests

2nd Stage: Field tests

Field work with the MIP system

2nd Stage: Field tests

Tests with the Soil

Color Optical

Screening Tool

(SCOST)

Direct push (whole

core) soil sampling

2nd Stage: Field tests

Soil Gas sampling with Post Run Tubing System (PRT)

Foto 6: Ensaio de amostragem direta de gases do solo pelo sistema PRT.

3rd Stage: Laboratory analysis of soil samples

Grain size, organic matter and fraction of organic carbon analysis

Foto 23: Abertura dos liners em bancada de laboratório.

Foto 24: Descrição táctil visual e coleta de amostras de solo para caracterização

geotécnica.

Soil description and sample collection

Results & DiscussionBench Tests – Response Curve

5% = LEL ≈ 300 mV

5%

300

MIP Field results - electric conductivity sensor (EC)

De

pth

(m)

EC/P1(mS/m)

EC/P2(mS/m)

EC/P3(mS/m)

EC/P4(mS/m)

EC/P5(mS/m)

EC/P6(mS/m)

0

1

2

3

4

5

6

7

8

9

10

11

A A’180 m

Geo-electrical cross section of study area (São Paulo Basin)

De

pth

(m)

EC/P1(mS/m)

EC/P2(mS/m)

EC/P3(mS/m)

EC/P4(mS/m)

EC/P5(mS/m)

EC/P6(mS/m)

A A’180 m

“ T E R T I A R Y ” ( S T r )

“ C O A R S E ” ( S Q a – F A r e )

“ T R A N S I T I O N ” ( S Q a - T r a n s )

“ F I N E ” ( S q a – A r g )

“ I N T E R B E D D E D ” ( D T e c )

“ F I N E ” ( D T e c )

“ C O A R S E ” O R “ F I N E ” ( D T e c )

????

?

?

0

1

2

3

4

5

6

7

8

9

10

11

De

pth

(m)

Groundwaterlevel

LithostratigraphicCharacterization

Lithostratigraphy

Technogenic Deposits

QuaternarySediments -

Silty Clay Lithofacies

QuaternarySediments -Transition

QuaternarySediments -

Sandy Lithofacies

Tertiary Sediments

MIP Field results - FID response to CH4

0,3 0,3 0,3 0,3 0,3 0,3

MIP Field results - FID response to CH4

MIP Field results - FID response to CH4

Integration of field and

laboratory results

De

pth

(m)

Conceptual Site Model

(CSM)

Conclusion

• MIP/EC can provide high resolution response for:• Soil electrical conductivity - Lithostratigraphy;• Detection and mapping of METHANE in the subsurface

(FID);

• Auxiliary field and laboratory techniques also providedvaluable information to support the interpretation andvalidation of the results;

• HRSC techniques contributed to achieve a detailed CSMfor the presence of methane in the study area.

Thank you

Leandro Gomes de Freitas

lfreitas@ipt.br

Institute for Technological Research - IPT