“…New landfills can be designed to prevent landfill gas accumulation even if no productive use of the gas is planned. Landfill gas control systems have been well documented in engineering practice (Weiss, 1974;Stone, 1978a,b;Goleuke, 1980;Shen, 1981;Stearns and Peyotan, 1981;EMCON, 1983;Pacey, 1984;Ghassemi et al, 1986;Walsh et al, 1988;Shen et al, 1990). In addition to gas recovery and active gas pumping, control measures include: (1) the installation of impermeable barriers before site operations to secure the perimeter of the landfill (cement walls, clay trenches, impervious liner materials such as plastics, rubber, asphalt, polyvinyl chloride, high density polyethylene, etc.…”