By Gary Eade, C.E.T., Manager, Environmental Operations, HETEK Solutions Inc.
Methane and carbon dioxide are two of the primary gases and are the main focus for worldwide emission reduction and control of greenhouse gases. Methane is the chief component of "natural gas" but also occurs naturally by the anaerobic decomposition of organic material in swamp areas, at landfill sites and at any location where organic deposits are present. Carbon dioxide is also produced by the decomposition of organic material as well as being a primary by-product of combustion. The detection, quantification and control of these two primary greenhouse gases were the main focus at the Kyoto "Conference on the Environment" in 1997.
Our company has played a pioneering role in the detection of hydrocarbon gases in North America. The initial focus of the company was the development of instrumentation and procedures to efficiently and accurately locate pipeline leakage. In recent years, this focus has expanded to include testing for a wide variety of combustible and toxic gases, including surface emission testing of landfill sites. With advances in existing technology coupled with the development of new technologies, the process of gas detection and monitoring has established new horizons. By combining several technologies, a cost-effective approach to surface emission monitoring of greenhouse gases over landfill sites and pipelines is gradually evolving as a proven technique.
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| Conducting DGPS perimeter study prior to starting surface emission analysis. |
By equipping All-Terrain Vehicles (ATVs) with modified and specialized Flame-Ionization (FI) instruments and a Differential Global Positioning System (DGPS), efficient and cost-effective monitoring of landfill sites is now a reality. Computer software has been developed and standard procedures are now documented in support of numerous trial surveys and scheduled projects. We refer to the project as our Methane Emission Monitoring System (MEMS).
A primary objective of the MEMS program is to effectively locate surface emissions of methane gas from active landfill sites using FI technology, and to plot the "hot spots" using a DGPS system. The mobile FI detection system was originally developed for the natural gas industry but is also ideally suited for methane gas emission studies at landfill sites. The DGPS system provides sub-metre accuracy for plotting emission locations at landfill sites. The use of ATVs provides enhanced area coverage over walking procedures, resulting in enhanced productivity and reduced costs.
Heath Consultants Incorporated (USA) developed the first truck mounted mobile flame-ionization unit in Newark, New Jersey in 1961. HETEK Solutions Inc., formerly Heath Consultants Limited (Canada), installed FI equipment on ATVs in 1993 and conducted several 1,000 kilometres of pipeline inspections in Alberta and Saskatchewan.
These units proved to be accurate and reliable for locating leakage on natural gas gathering and transmission pipelines. In 1996 a mobile FI/ATV unit was re-designed for landfill gas emission testing and was further equipped with relatively new DGPS equipment and interface software. These units are available and can meet the New Source Performance Standard (NSPS), drafted on March 12, 1996 in the United States. This standard requires that all large landfill sites be inspected for methane gas emissions.
Walking landfills with portable FI instruments to locate surface emissions of methane gas is time-consuming and costly. With the aid of an ATV more ground can be covered quickly and effectively, thus reducing mandatory inspection costs. All required reporting can be generated directly from the computer. Projects completed to date indicate increased productivity to average about 400% over conventional walking procedures, with enhanced documentation and reporting. Monitoring accuracy is equivalent to or better than previous conventional methods of surface emission testing and the procedure is recognized by Environment Canada as the "study evaluation of choice".
Our current system has sub-metre accuracy within the point of reference. We use either the "Coast Guard Beacon Satellite" system for areas near water or the "Satellite Lock" system for inland areas. If required, a "Real Time Kinematic" (RTK) GPS unit can be provided for "survey grade coordinates" typically within +/- 0.1 feet. Locations will be recorded to the nearest foot.
The City of Calgary has now completed three years of seasonal methane gas surface emission testing (spring and summer) at four large landfill sites. Environment Canada has also conducted follow-up studies, where "hot spots" were detected, for quantifying off-gassing at these landfill locations.
We can now provide the Optical Methane Detector (OMD) system using infrared technology. These units should improve the ability to operate in extreme weather conditions and allow for higher speeds consistent with terrain conditions. The OMD is designed to perform 14,000 measurements per second, thus providing immediate response. In the future, this technology could make ATV emission testing even more cost-effective. Currently, the capital cost for the OMD system is approximately four times that of the FI system.
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