"Flux box monitoring of methane emissions from the surface of
permitted or licensed landfill sites is of growing interest to site
operators." Methane emissions through the cap of a landfill need to be
monitored as an integral part of demonstrating compliance with the Landfill
Directive, and in particular to: identify faults in the gas management system at a site and
prioritise the remediation required; quantify the total emissions of this important greenhouse
gas from the site as a whole. The Monitoring guidance applies to: filled and restored phases of an operational or closed
landfill with a permanent cap; temporarily capped zones of an operational landfill not
currently accepting wastes and not expected to do so within three months. The monitoring of emissions through a landfill cap has two
stages. Initially, a simple survey demonstrates whether there are
inadequacies in the gas containment and collection system. Only when these
deficiencies have been located and remedied such that the concentration of
gas above the surface is low is it appropriate to begin a quantitative
survey of surface flux. Subsequently, the flux of methane emitted through the
intact cap is measured at a number of representative points using an array
of flux boxes. From these individual measurements, the average flux from
the capped zones is calculated. This identifies where the gas flux exceeds
an emission standard set by For more information on: monitoring services; supply or hire
of boxes; and free advice call: 
the Environment Agency.
related links: