Laser Gas Detection Success

Anglian Water Services (AWS) wanted to quantify methane emissions from their wastewater treatment processes. As these are less well understood and less well defined than indirect carbon emissions associated with electricity use, they set up a project to locate and quantify emissions from the processes at a wastewater treatment works. This was led by the in-house Innovation Team which undertakes research and development to deliver environmental benefit, cost saving and operational efficiency. A laser-based TDL-500 portable methane leak detector supplied by Geotech (UK) was used for the project. In the three-month study they pin-pointed and quantified methane emissions around the plant, including those around secondary digesters, activated sludge plants, anaerobic digesters and gas holding tanks.

“We were able to successfully confirm patterns of methane emissions from activated sludge lanes, backing up results found worldwide by others studying similar trends in the literature. We were also able to use the TDL-500 probe to quantify methane emissions from the surface of secondary digesters. The TDL-500 was selected due to its accuracy in measuring methane with a sensitivity of 1 ppm. Its portability and ATEX certification were also vital in this project as it was used in potentially explosive zoned areas around anaerobic digesters. A critical benefit of the TDL-500 in this project was its ability to measure methane concentrations in two ranges (0-10,000 ppm and 0-100% volume gas). This was of great importance as gas emissions from various processes were analysed, all of which contained different concentrations of methane,” said Astrid Bosmith, Innovation Technologist with AWS.

AWS serves around 5.8M waste-water customers and operates 1,114 waste water treatment works.

Using laser spectroscopy technology, the TDL-500 from Geotech can detect methane leaks in applications ranging from natural gas pipelines to landfill or coal mining sites. The tunable diode laser detects methane at 1ppm. ATEX certification to Zone 1, it can be used in most hazardous areas, detecting methane leak locations with speed and precision.

The laser technology, unlike FID devices, does not a flame or a hydrogen gas supply, avoiding transportation of hazardous gases. Fast response times mean less time spent monitoring and GPS helps record leak position, set up routes and record readings. The portable TDL-500 laser leak detector is easy to carry for one person to use on foot. It lasts 8-10 hours between charges. Users are likely to be involved with natural gas networks, landfill gas surface emission checking, biogas feeds to CHP engines, water treatment plants, momentary methane leak detection and sewerage system methane detection.

Wastewater processing gas leak detection with Geotech equipment is a very helpful addition for waste-water treatment site operators. Many of these already use Geotech portable and static gas analysers to check biogas production volumes and quality ahead of using it in CHP engines to produce electricity and heat. Examples reported earlier include sludge AD biogas analysis in Turkey, monitoring AD and keeping sludge AD working while, ‘On Gas Watch 24/7' - showed the silent sentinel role for static gas analysis at United Utilities.