Abstract
Methane landfill emissions are a general concern and should be estimated for taking the proper measures for global warming
mitigation. The European legislation is supporting all techniques that avoid, reduce or treat CH4 emissions. One of the main
directions is reducing the quantities of biodegradable waste disposed in landfills. The efforts for GHG emissions reduction and
also compliance with European legislation in the field of waste management does not mean only putting in place some state of
the art facilities but also to operate them in optimal conditions at design capacity. The new projects for Integrated Waste
Management Systems, developed in most Romania counties, include as compulsory stage in the design of the new landfills, a gas
treatment system in accordance with Directive on the landfill of waste. By treatment of the landfill gas, the CH4 is oxidized to
CO2 that has a global warming potential of 21 times less than CH4. It is foreseen that these systems will be put into operation
after closing the first cell that has variable life time, frequently between 6 and 8 years, meanwhile most of the generated methane
will be released into the atmosphere. The legislation does not mention at what stage the landfill gas has to be collected and
treated. In this way “after cell closure” could mean a significant delay in compliance. Various first kinetic order models of
methane generation potential are briefly presented. They are widely used having advantages and drawbacks and could be used to
predict the methane emission/generation before and after landfill closure.