Landfill Gases Easily Monitored
The new PGSi Programmable Monitoring System from Crowcon can monitor up to four different landfill gases at once from up to 32 individual sampling points. Using Windows XP-based software, the PGSi is ideal for monitoring landfill gas in boreholes or for protecting buildings such as schools, hospitals, retail parks and houses built on landfill sites. By doing away with the need for multiple fixed detectors, the sampling system significantly reduces installation and maintenance costs.
Each sample line can be up to 1km in length and the sample times for each point are individually adjustable and can be sequenced in any order. A dual pump arrangement ensures that samples reach the gas sensors as quickly as possible. Filters, flow-fail devices, internal gas leak detectors and flame arrestors are all fitted as standard to ensure safe and reliable operation at all times.
The system is controlled by a PC which displays individual sample locations, gas levels and alarms. It operates up to 32 relays (which activate alarm devices or send a signal to external control equipment) and provides comprehensive data-logging facilities, with gas data displayed either in tabular or graphical formats. The PC can be monitored remotely via an optional modem, allowing status checks and the uploading of datalog files. The system can be supplied with a PC or can operate with a PC supplied by the user.
Common gas hazards associated with landfill sites include methane, carbon dioxide and hydrogen sulphide, as well as others, depending on the landfill’s content. Methane poses a severe explosion risk, is damaging to plant life and is also a greenhouse gas. Carbon dioxide, also a greenhouse gas, is toxic and an asphyxiant, as it depletes local oxygen levels. Hydrogen sulphide is highly toxic, even at very low concentrations.
These gases are generated during the working life of a landfill site and for as long as 30-40 years after a site has been covered over. The UK Landfill Regulations (England and Wales) 2002 stipulate that all landfill site operators carry out effective monitoring of these gases for a set period after closing, as stipulated by the Environment Agency.