Closed (or historic) Landfills
A ‘closed landfill’, also called a historic landfill, is a landfill that was operated by a local authority for the recovery or disposal of waste without a waste licence on any date between 15th July 1977 and 27th March 1997. Closed landfills have to be retrospectively controlled or ‘licensed’ by the Environmental Protection Agency (EPA), via a ‘Certificate of Authorisation’.
The purpose of a Certificates of Authorisation (CoA) is to specify control and remediation measures required at a closed landfill to ensure that waste disposed or recovered in the closed landfill is not causing, or is not likely to cause, environmental pollution. These matters are provided for in the Statutory Instrument Waste Management (Certification of Historic Unlicensed Waste Disposal and Recovery Activity) Regulations, 2008 and require the registering of closed landfills, carrying out of risk assessments, applying for CoA’s from the EPA, complying with the conditions of the CoA.
One of the risks posed by landfills is from landfill gas, which is principally composed of methane and carbon dioxide and other minor constituents. When uncontrolled, risks posed by landfill gas include: flammability and explosion risks, asphyxiation risks, potential health impacts, odour impacts and global warming potential.
The environmental risks can be mitigated by restoring the landfill through covering or ‘capping’ it with an artificial liner and soil, grassing or landscaping the finished surface and the ongoing aftercare of the site, in order to control emissions.