This project aims to develop cost-effective biotechnological methods for the abatement of ground and surface water pollution by leach ate from landfills and forth mitigation of methane emissions by the use of efficient upper microbiological filter layers. Leach ate treatment will involve the use of combined anaerobic-aerobic systems, with post treatment to ensure metal and inorganic nutrient removal. Reduction of landfill methane emissions will focus on the ability of psychotropic and psychrotolerant methane-oxidising bacteria to remove methane under a variety of ambient climatic conditions. The results obtained will be of value for the bioremediation of closed or still poorly-managed and badly-sited landfills as well as for the proper operation of new correctly designed and well-managed sites.