Geotech’s GA5000 landfill gas analyzer is helping Exea Associates, a UK-based emissions and landfill gas recovery consultancy, understand changing gas mix and pressure as gas generation slows on a closed landfill site.
Before using the GA5000, Exea consultants would take methane, carbon monoxide and oxygen levels to calculate the residual nitrogen level. The GA500 makes this calculation directly. The single data screen on the analyzer gives Exea a good idea of how a landfill site is functioning so they know when and where to investigate and what to look for.
Exea is also using the GA5000 to develop new investigative techniques, such as depth profiling in a borehole. Exea does this by dipping the well to check the water level and then sampling gas at 0.5 meter above the water surface and using the GA5000 to take measurements as they come up the well.
Exea has seen an increase in hydrogen levels on many landfill sites recently. Even at low levels, hydrogen can interfere with carbon monoxide readings, which is problematic because carbon monoxide can be used as an indicator of underground fires. The hydrogen-compensated carbon monoxide sensor available on the GA5000 can correct the carbon monoxide reading up to 10,000ppm of hydrogen, and an indicator on the screen shows when hydrogen is at a level that may interfere with carbon monoxide readings.
Exea consultants find the GPS option on the GA5000 helpful, particularly on older landfill sites where the boreholes can be overgrown and difficult to find.
The consultants also use the analyzer’s data management capability, so instead of writing down readings, consultants can download all the data, such as leachate dipping levels, which are entered straight onto the analyzer. They can then use the Gas Analyzer Manager (GAM) software to create reports.
Photo: closed landfill site via Shutterstock.