The landfills have been designed as a, And constructed secure containment facility incorporating multilayer composite liner systems covering the full area area of the site. As the sites landfill gas, Are lined and contaminated liquid within the landfill know as leachate can be collected and treated to guarantee that there is going to be no untreated discharges from the landfill to the environment. The geomembrane incorporated into the landfill liner systems with 60 mils 0. 06 inches thick and must be composed of a material such with a dense composition polyethylene hdpe that is extremely low in permeability. The material must also have chemical and physical characteristics characteristics which do not adversely affected by the placement of waste or by contact with leachate. Linear reduced-density polyethylene lldpe and ultra-durable polyethylene with high density hdpe are materials typically specified for geomembranes in solid waste landfill cover systems. A geomembrane barrier used in landfill final cover system must be no fewer than 40 mils thick if comprised of lldpe or a minimum of 60 mils thick if it is comprised of hdpe. The 60 mils minimum thickness for hdpe geomembranes is to achieve proper field seams.