Experts at the 1997 Kyoto environmental conference resolved to develop emission reduction and control strategies to focus on two primary greenhouse gases: methane and carbon dioxide.
Methane is the chief component of natural gas but also occurs with the anaerobic decomposition of organic material in swamp areas, landfills and other organic-deposit areas. CO2 is produced by the decomposition of organic material and is also a primary combustion by-product.
Spurred on by Kyoto, innovative strategies are being developed to detect, quantify and control these gases. One company — London, Ontario-based HETEK Solutions Inc. — initially focused on the development of instrumentation and procedures to locate pipeline leaks. In 1993 the company developed mobile detection systems in Alberta and Saskatchewan for this purpose. But in 1996 the system was re-designed for landfill gas emission testing and was further equipped with new DGPS equipment and interface software. These units meet the New Source Performance Standard (NSPS), drafted on March 1996 in the U.S., which requires that all large landfill sites be inspected for methane gas emissions.
HETEK now equips all-terrain vehicles (ATVs) with modified flame-ionization (FI) instruments and a differential global positioning system (DPGS) to enable efficient monitoring of landfill sites.
The company’s methane emission monitoring system (MEMS) effectively locates surface emissions of methane gas from active landfill sites. Environment Canada recognizes MEMS as a “study evaluation of choice.” The mobile detection system and the DGPS provide sub-metre accuracy for plotting emission locations.
The use of ATVs provides enhanced area coverage over walking procedures and results 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.)
The system uses 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” (RKT) GPS unit can be provided for survey-grade coordinates typically within +/- 0.03 metres.
The City of Calgary recently completed three years of seasonal methane gas surface emission testing (spring and summer) at four large landfill sites. Environment Canada also conducted follow-up studies at these landfill locations. Projects completed to date indicate increased productivity by 400 per cent over conventional walking procedures, with enhanced documentation and reporting.
To efficiently measure landfill emissions, one must consider weather conditions and barometric pressure. Seasonal comparisons have found lower emissions during spring and fall projects when compared to similar projects conducted during warmer summer conditions. The location of “hot spots” seems to remain constant for the most part, but the emission areas tend to be larger during summer conditions.
Soil moisture is also a decisive factor in the rate of activity. Surface emissions are reduced when site conditions are damp, particularly in the northern regions. For reliable results dry surface conditions are preferable.
In-situ testing of gas levels tends to be higher in the summer months due to better venting conditions. High readings under a frost cap are not unusual in Canadian landfill sites. As the soil cools in the winter months there appears to be a drop in anaerobic activity in shallow sites but not to the same extent in the deeper sites.
The newest addition to MEMS is the Optical Methane Detector (OMD), which uses infrared technology to 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. Currently, the capital cost for the OMD is approximately four times that of the FI, but eventually (with equipment part innovation) this technology could make ATV emission testing even more cost effective.
Gary Eade, C.E.T. is manager of environmental operations for HETEK Solutions Inc., based in London, Ontario.