25. An engineered landfill must have a system capable of collecting leachate and conveying it towards a treatment or discharge site. The collection system must incorporate the following components:(1) a drainage layer placed across the base and sideslopes of the disposal areas over the soil liner or the geomembrane, as the case may be, and which, to a minimum depth of 50 cm,— consists of materials having less than 5% by weight of particles 0.08 mm or finer in diameter;
— has a constant minimum hydraulic conductivity of 1 x 10-2 cm/s.
The drainage layer must not impair the integrity of the underlying geomembrane, if any;
(2) a network of drainage pipes and collectors embedded within the drainage layer on the bottom of the disposal areas. The pipes must— have a smooth interior and a minimum diameter of 150 mm;
— have no synthetic filter sock;
— have a minimum slope of 0.5%;
— have cleanout ports.