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TECHNICAL NOTE

A Field Demonstration: Monitoring GSE Leak Location Liner for Leakage

The Wengfu Company is a state owned enterprise , with a large

manufacturing facility in Guizhou Province, Peoples Republic

of China. Several industrial chemicals are produced there and

the facility includes a large fertilizer (phosgypsum) processing

operation with a gypsum stack of approximately 20 hectares

and an average depth of 120 meters, a water storage pond lined

with a 1.0 mm HDPE black geomembrane that is approximately

3 hectares in size and process water ponds lined with a 1.5 mm

HDPE black geomembrane that is approximately 4 hectares

in size. Over the past decades, the area has experienced

significant groundwater and surface water contamination.

This occurred primarily during the initial operation years and

geosynthetic barriers were not utilized. Subsequently, the use

of geomembranes for containment and groundwater protection

became a standard practice and the areas environmental quality

increased significantly. Due to continued manufacturing and

existing storage capacity constraints the current gypsum stack

is expected to reach its capacity in the next few years. Plans

are underway to construct and expansion that will combine two

existing storage areas, cap a significant portion of the exposed

stack and provide a base liner layer for a significant “piggy back”

expansion. Due to the critical nature of this expansion the owner

and the provincial Department of the Environment determined

to construct a test pad designed to demonstrate the current best

available technology and to provide engineering data and training

for the inclusion of these techniques in the site expansion(s).

Testing and Results The installation of the geomembrane was fairly straightforward. Standard quality

assurance parameters were followed including preparation of test welds, air channel

pressure testing for the dual track wedge welded seams and vacuum box testing for

extrusion welded seams. Care was taken to provide electronic isolation by leaving the

anchor trenches open and leaving the exposed perimeter edge of the geomembrane

exposed to the air. Also panel to panel connections were made with approximately

1 meter by 2 meter sections of White Leak Location Liner being placed underneath

the primary geomembrane and the two conductive surfaces connected via gravity

connections with a small hot air tack weld to assure stability of the placement. The GSE

ISO (isolation) wedge was used for all dual track wedge welds to assure proper isolation

of the conductive edges and prevent “false positive” leakage results.

Authors B. J. Ramsey

GSE Environmental

Suzhou, PRC

N. Liu

Shanghai Jiao Tong

University

Shanghai, PRC

E. Geutebrück

Texplor GmbH

Potsdam, Germany

GSE Leak Location Liner

This Information is provided for reference purposes only and is not intended as a warranty or guarantee. GSE assumes no liability in connection with the use of this Information. Specifications subject to change without notice. GSE and other trademarks in this document are registered trademarks of GSE Environmental, LLC in the United States and certain foreign countries.

Field Demonstration: Monitoring GSE Leak Location Liner

Photo 1. Demonstration pad site prior to geomembrane installation.

Photo 2. Pad after geomembrane installation.

Figure 1. GSE Leak Location Liner welding schematic with false positive result potential.

Figure 2. GSE Leak Location Liner welding schematic with ISOWedge weld attachment.

Figure 3. Spark testing.



After completion of the installation and standard quality assurance

testing, a liner integrity survey was conducted in accordance with

ASTM 7240. The seams were particularly evaluated and several minor

installation errors were detected and repaired with extrusion beads.

At that point three monitoring modules manufactured by Texplor

were installed in a triangular geometry as pictured and illustrated on

the result schematic below. The modules are enclosed in an HDPE

(High Density Polyethylene) case and the modules were provided

with a weldable HDPE skirt/flange. The flange was traced into the

geomembrane with a slight reduction in size, the geomembrane

plaques cut out and removed and the modules placed under the

geomembrane (flange only) and extrusion welded into place. Care

was taken to avoid damage to the cables leading from the modules

to the receptor plugs. Subsequently theses welds were tested with a

vacuum box.

After installation of the modules, the wiring was connected to a

master control panel and the system was powered and calibrated.

A background state was established. After assuring the system was

fully operational, a trial hole of approximately 1.5 centimeters in

diameter was punched through the liner in a location approximately 3

meters form one of the sensors and within the triangle formed by the

three sensors. The signal of leakage/electrical disruption was evident

in less than 30 seconds. This hole was then repaired with a patch and

extrusion weld.

The site was then flooded with water to a depth of between 10-25

centimeters (depending on the location as the site sloped slightly

downhill, west to east.)

At that point the personnel of the module manufacturer and

geomembrane manufacturer left the premises and a “blind” hole

(again approximately 1.5 centimeters in diameter was placed

in the geomembrane by the province officials present for the

demonstration. The staff returned and the lack of liner integrity was

immediately identified and data was collected to assist in calculating

the location of the “blind” hole.

Photos 3 and 4. Module Installation.

Photo 5. Flooded pad with modules.



Subsequent data analysis (taking approximately two hours)

indicated the location of the leak/hole with an estimated accuracy

within a 1 meter circle. This calculated location was compared with

the measured /actual location and varied by 68 centimeters.

At that point, phos-gypsum waste was placed on the pad to a

depth of 40 centimeters. During the waste placement, the majority

of the water was drained from the pond; however, some standing

water remained. After the waste was placed, the three sensors

were excavated and removed by being cut out of the liner system.

The cutouts were not repaired or covered with any additional

liner material. The edges of the cutout areas were lifted to assure

electrical isolation.

After that point a dipole (quadrapole) survey was done in

accordance with ASTM 7007. The dipole survey took approximately

one and one half hours to conduct and identified three potential

leaks as the outcome of a 15 minute review. These leaks were

pinpointed using the dipole apparatus and successful identified two

“blind” leaks that had been placed in the system.

Photo 6. Officials visit the site.

Figure 3. Leak location results.

Photos 7 and 8. Cover soil placement and site after completion.

Photo 9. Diopole (quadrapole) testing.



Figure 4. Diopole survey results.

One of the holes, nearer to the center of the site, was very accurately located to a distance of just a few centimeters.

The other leak was closer to the edge of the liner, and because of some edge distortion effects, the accuracy was not

quite as good; however, it was still within a 20 to 30 centimeter radius. The third signal could not be clearly identified as

a hole and as no excavation was done, this issue was left open.

Conclusion

The testing and data demonstrated all of the current “best practices” and “best available technologies” for barrier

systems. One of the most effective methods of assuring barrier performance has been demonstrated to be an electrical

leak location survey that is conducted after initial cover soil placement above (on) the geomembrane (Beck, 2012). The

placement of cover soil on the geomembrane has been reported to be the most dangerous time and the most likely to

result in a loss of barrier capability (Nosko). Furthermore, electrically conductive geomembranes have a very strong

history of supporting and improving the performance of liner integrity surveys (Beck, 2015). The monitoring technology

demonstrated here can provide continuous monitoring further improving environmental protection.



REFERENCES

ASTM D5820 - 95(2011) Standard Practice for Pressurized Air Channel Evaluation of Dual Seamed Geomembrane,

American Society for Testing and Materials, West Conshohocken, Pennsylvania, USA

ASTM D7002. Standard Practice for Leak Location on Exposed Geomembranes Using the Water Puddle System,

American Society for Testing and Materials, West Conshohocken, Pennsylvania, USA.

ASTM D 7007 – 09 (2009), “Standard Practices for Electrical Methods for Locating Leaks in Geomembranes Covered

with Water or Earth Materials”, American Society for Testing and Materials, West Conshohocken, Pennsylvania, USA.

ASTM D7240. Standard Practice for Leak Location using Geomembranes with an Insulating Layer in Intimate Contact

with a Conductive Layer via Electrical Capacitance Technique (Conductive Geomembrane Spark Test), American

Society for Testing and Materials, West Conshohocken, Pennsylvania, USA.

ASTM D7703. Standard Practice for Electrical Leak Location on Exposed Geomembranes Using the Water Lance

System, American Society for Testing and Materials, West Conshohocken, Pennsylvania, USA.

Beck, A. (2012) “A statistical approach to minimizing landfill leakage” SWANA, Washington D.C. Conference

Proceedings.

Beck, A., (2012) . “How Much Does my Landfill Leak?” Waste Advantage Magazine,

Beck, A. (2015). “Available Technologies to Approach Zero Leaks”. Proceedings Geosynthetics 2015, Portland, Oregon,

USA

Brouwer, R. and Veldhuizen, F. (2011): Texplor Lekdetectie beij bouwputten. 61, GEOTECHNIEK.

Bruchem, H. van and Kraneburg, J.K. (2015). Winst op alle fronten – ruim baan voor innovatie (Texplor technologies).

SIKB Bodembeheer, protocol 6702 for geo-electrische meting. 20, SIKB, Netherlands

Forget, B., Rollin, A.L. and Jacquelin, T. (2005) “Lessons learned from 10 years of leak detection surveys on

geomembranes” Proc. Sardinia 2005, Sardinia, Italy.

Geutebrueck, E. (2014). Nouvelles technologies pour le contrôle qualité des geomembranes. Ales, Tunesia.

Geutebrueck, E. (2011). Leak detection in complex underground structures – Metro Station, Gondar, Rome, Italy, OIAV,

155, 7-9/2010, 281 – 285, Österreichischer Ingenieur und Architekten Verein, Austria.

Kemnitz, M. and Oritz, J.,”. Improving Geomembrane Installations and CQA Through Leak Location Surveys”,

Proceedings Geosynthetics 2015, Portland, Oregon, USA

Koerner, R. M. (2012). Designing With Geosynthetics, 6th ed., Xlibris Publ. Co., USA

Nosko, V., and Touze-Foltz, N., (2000) “Geomembrane Liner Failure: Modelling of Its Influence on Contaminate

Transfer”, Proceedings of the Second European Geosynthetic Conference, Patron Editore, Bologna, Italy, pp-557-560.

Ramsey, B., Peggs, I. et.al (2012) “New Electrically Conductive Geomembrane For Post Installation Liner Integrity

Surveys”, Proceedings of the Fifth European Geosynthetic Conference, Valencia , Spain, Volume 2, pp-251-256.

Rotmans, M. and Ramakers, P. (2014). Neem vaker een kijkje in de bodem (electric technologies Texplor). Bodem,

numer 5, Netherlands

Rotmans, M. (2014): Permanent Lekdetectie Systeem (Texplor). 21, Pompshop, Netherlands

Rowe, R.K. and Hosney, M.S., (2010) “A Systems Engineer-ing Approach to Minimizing Leachate Leakage from

Landfills”, 9th International Conference on Geosynthetics, Brazil 2010, pp. 501-510.

This Information is provided for reference purposes only and is not intended as a warranty or guarantee. GSE assumes no liability in connection with the use of this Information. Specifications subject to change without notice. GSE and other trademarks in this document are registered trademarks of GSE Environmental, LLC in the United States and certain foreign countries. 30MAR2016

GSE is a leading manufacturer and marketer of geosynthetic lining products and services. We’ve built a reputation of reliability through our dedication to providing consistency of product, price and protection to our global customers.

Our commitment to innovation, our focus on quality and our industry expertise allow us the flexibility to collaborate with our clients to develop a custom, purpose-fit solution.

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REFERENCES

Stoel, A.E.C. van der, (2013): Waterremmende bodeminjectie (with Texplor Leak detection technologies), 19,

GEOTECHNIEK.

Tissing, A. (2010): AMSTERDAM – lekdetectiemeetingen Texplor. Cobouw 7-12-2010, Netherlands

Youngblood, J.R. US Patent 9033620 B2, Leak detectable geomembrane liners for containment system and method of

testing for leaks. Issued May 19, 2015

Weiss, B., and Geutebrueck, E. (2014). ): Next generation Leak Location in HDPE liners in landfills and other facilities

of environmental risk (Texplor MSS Monitoring System). 10. IGS Conference, Berlin, Germany.

Weiss, B., and Geutebrueck, E. (2013): Next generation Leak Location in HDPE liners in landfills and other

environmentally sensitive infrastructures (Texplor MSS Monitoring System). 14. International Waste Management and

Landfill Symposium

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