Leachate Collection and Management System
Leachate is liquid, primarily rainwater, which passes through the waste. The leachate collection system at American Landfill is comprised of a leachate drainage layer installed on the floor and side slopes of the lined landfill cells. American Landfill utilizes a geocomposite layer (highly permeable layer geosynthetic net adhere to two layers of geotextile on either sides) on the side slopes of the lined cells. A geotextile overlain on top of geonet is utilized as the drainage layer on the floor of the lined cell.
Six inch perforated, schedule 80 PVC piping network is installed on the floor of the lined cells. Leachate that is collected on the floor of the lined cells flows by gravity to a leachate collection sump located within the cell. Each leachate collection pipe is connected by long radius pipe fitting(s) to a leachate cleanout pipe(s). The leachate cleanout pipes are installed approximately 500 feet apart. Leachate lines are inspected after placing the first lift of waste and annually thereafter. A high-pressure water jet equipped with a nozzle is injected through the cleanout pipe and leachate collection pipe to verify integrity of the pipe and also to clean the leachate lines.
A submersible sump-pump pumps leachate collected within the sump to an above ground 250,000-gallon leachate storage tank. The submersible pump in conjunction with an electrically programmed pressure transducer ensures that the leachate level on top of the liner system is below one foot. Leachate transfer components such as forcemain pipe, risers, manholes and other ancillary components including leachate storage tank that are located outside the lined areas have a secondary containment or a leak detection system.
The leachate storage tank is equipped with pumps and a load-out facility. Leachate from the storage tank is pumped into a tanker truck, which transports leachate to the City of Alliance wastewater treatment plant for treatment and disposal. American Landfill has also obtained approval from the Ohio EPA to recirculate leachate back into waste in the lined areas of the facility.
In accordance with the leachate recirculation plan, leachate is recirculated back into the waste by a series of perforated pipes and control valves located within the waste. Leachate recirculation is the newer technology which is utilized within the solid waste industry. Leachate recirculation provides beneficial uses such as acceleration of waste decomposition and waste degradation. This process, in turn, accelerates landfill gas production and promotes waste settlement that reduces maintenance of landfill cap components.