A DIFFERENT GAS GENERATING REGIME WITHIN LOW-CARBON WASTE LANDFILLS IN THE UK AND EUROPE

In low carbon waste landfills the availability of water or a carbon source, or the

build up of toxic compounds appears to limit anaerobic gas generation. Thus oxygen consuming

chemical/biological reactions occur immediately after the waste is placed, but factors required

for anaerobic degradation become exhausted, perhaps because of limited permeability that also

appears to be a feature of this waste. Oxygen and its reaction products, principally carbon

dioxide, are removed by phase change from the gas filled pore space of the waste. This results in

the proportion of nitrogen in the pore gas rising to more than the 80% typical of atmospheric

composition. Nitrogen gas enrichment through oxygen removal can mean either negative

pressure within the landfill, or slow air ingress into the waste. New gas management and

monitoring techniques at such sites should reflect this different conceptual model.