The Simi Valley Landfill is designed to dispose of non-hazardous solid wastes. All disposal areas are constructed with a composite liner system and leachate collection system. The leachate collection system gathers wastewater that is generated by the overlying municipal solid waste.
The primary liner consists of a synthetic 60-mil-thick high-density polyethylene (HDPE). Under the primary liner is 2-ft of low permeability soil, or equivalent material. Together, these two components of the liner system prevent contaminants from penetrating the surrounding environment.
The leachate collection system consists of synthetic drainage material called geocomposite. The geocomposite is comprised of high-density polyethylene channels manufactured to rapidly convey liquids such as leachate. It is considered to be an acceptable equivalent to one-foot of granular drainage material. A non-woven filter geotextile is attached to prevent infiltration of soil that will clog the geocomposite. Base grades are sloped to a central collection sump which is designed for subsequent removal of leachate to an onsite storage tank.
All areas of the liner system are protected by a 1.5 ft thick soil layer. The soil layer prevents the overlying waste from penetrating and damaging the liner system.
Open refuse is minimized by the construction of daily work areas sized to handle only each day's volume, and subsequently covered and sealed with soil at the end of each day.