The AB Lime landfill takes all of Southland’s municipal household waste with some special industrial wastes as well.
As a Class A landfill we adhere to strict standards – including site selection to reduce the potential for adverse environmental effects, engineered systems for leachate containment and collection systems for both leachate and landfill gas.
The landfill is lined with a technical and comprehensive series of impermeable layers. This ensures that waste and leachate is confined within the landfill that would otherwise leach into the surrounding environment.
The surrounding environment is monitored frequently weekly and monthly for potential impacts the landfill may have on the land and waters.
Landfill gas is a by-product from the decomposition of organic waste found in landfills. Landfill gas is typically made up of 30-50% of methane, 30% carbon dioxide and trace amounts of other gases.
Methane is a very potent greenhouse gas and with no collection it would simply rise, leave the landfill and go into the atmosphere and contribute to global warming.
At AB Lime landfill gas is captured and controlled by a series of gas wells before it is collected and then burnt at a flare that destroys the methane and turns it into carbon dioxide and water.
Landfill gas is a useful fuel source and a project is under way at AB Lime to utilise the landfill gas to fuel our coal fired lime kilns that dry our agricultural lime. This will greatly reduce the coal burnt at AB Lime - thereby reducing our carbon footprint.
Leachate is water that has moved through the waste mass in the landfill picking up dissolved contaminants and suspended material. Landfill leachate varies in composition depending on factors such as the type of waste deposited and the age of the waste.
The leachate moves through the waste mass until it collects in the leachate collection layer. A series of pipes feed the leachate into the leachate collection tank.
In the tank an aerator increases the quality of the raw leachate reducing the chemical and biological oxygen demand. Leachate is either recirculated back into the landfill or is tankered to a wastewater treatment plant for further treatment.