Location of Hydrocarbon Leakage by Combining SPME in Optical Fibers and OTDR Techniques

Abstract

Leaks in the bottom composite liner of landfill or chemical waste disposal containments may lead to the penetration of contaminated leachate through the barrier and transport of toxic substances into the surrounding soil and groundwater. Therefore continuous surveillance of landfill liners and the identification of leaks are essential parts of waste management. For other large technical installations, e.g., chemical production plants, tank farms, or pipelines extensive leakage monitoring is even more imperative, because fast detection and localization of a leak is required to prevent the release of huge amounts of hazardous chemicals and new contamination of the environment. However, fast identification of a leak position in a chemical waste disposal site may be difficult, e.g., if the site is lined with an underground geomembrane most leaks are point sources, not widespread. Owing to the large spatial extension of such technical facilities, comprehensive and distributed monitoring techniques are necessary. In this context fiber-optic chemical sensor systems with distributed sensing cables buried under the liner, e.g., in a grid–type of scheme, could be a valuable tool.