Landfills are used routinely for disposal of urban solid waste on a patch of identified land. Landfill land needs to be secured and engineered in such way so as to minimize hazardous environmental impact. In this article I will discuss few general types of landfilling methods that are practiced for the disposal of urban solid waste.
1. Cell Landfilling Method
Cell landfilling method is a progressive filling and restoration concept that advocates tidy disposal of waste. Cell landfilling involves depositing collected waste in a pre-constructed bonded area.
2. Trench Landfilling Method
Trench method is also known as Below Ground Landfill. Trench method of landfilling involves excavation of a waste trench. Collected Waste is disposed inside excavated trench and is covered-up with a layer of soil. This method is suitable only for small quantity of waste. Trench landfilling method may not be suitable for large quantity of waste because larger trench needs to be excavated with proportionate increase in the cost of disposable.
3. Area Landfilling Method
Area landfilling method is also known as Above Ground Landfill. Area landfilling is mostly used to dispose urban waste. Area landfilling method involves depositing waste in layers and forming terraces over an identified landfilling area. Area landfilling method generates excessive leachate, which is not only difficult to control but will also pollute ground water table.
4 Slope Landfilling Method
Slope landfilling method involves disposing collected waste along the sides of existing hill slope.
5. Valley Landfilling Method
Valley Landfilling Method is also known as Canyon Landfills. In valley landfilling method collected waste is deposited in valleys, low-lying areas, canyons, ravines etc.
6. Combination Landfilling Method
More than one of the above listed landfilling methods are employed in combination to dispose off collected waste.
In all the above methods precautions needs to be taken to prevent harm to mother nature. Various contamination may occur during landfilling of urban solid waste.
- Air contamination due to waste generated gases, windblown waste litter and waste dust, waste generated stench
- Surface water contamination through waste runoff, slope failure etc.,
- Ground water contamination through leachate seepage
- Rodents, pests, fire, bird menace
- Contaminated Waste soil erosion etc.,
Thus care should be taken to cover the landfill with a suitable inert material such as high density polyethylene (HDPE) to a minimum depth of 15cm. thereby minimizing windblown waste litter, waste dust and also reducing the bad odours generated by decomposing wet waste.