Purpose of Landfill
A landfill is basically a managed and monitored waste disposal site (dump). Landfills are used for many things such as waste management, solid waste deposits, non hazardous waste deposits and many more. Landfills are used to facilitate the break down of non recyclable waste. The waste is buried and isolated from environmental surroundings. The rubbish is easily broken down by bacteria due to the lack of oxygen under the ground. Landfills are either built into the ground or above the ground. They use many vehicles and machines to move the rubbish around and in order to abide by the rules set to protect the environment and manage waste. A world-wide organisation EPA (Environmental Protection Association) was created in 1970 to provide rules and regulations regarding landfills and many other sites. Landfills also must be monitored for 30 years after their closure.
Basic rules of landfills
1. Must use the smallest area possible
2. Waste must be compacted to reduce volume
3. All vehicles must go through a weigh-in bridge, be inspected and have their tyres cleaned
4. No recyclable items to be dumped
5. Must have EPA approved seals
6. Minimise the impact on the surrounding environment
7. Site must be approved by EPA
8. Be monitored for 30 years after their closure
2. Waste must be compacted to reduce volume
3. All vehicles must go through a weigh-in bridge, be inspected and have their tyres cleaned
4. No recyclable items to be dumped
5. Must have EPA approved seals
6. Minimise the impact on the surrounding environment
7. Site must be approved by EPA
8. Be monitored for 30 years after their closure
Types of landfills
There are 4 types of landfills, the 3 main types are, municipal solid waste, construction and demolition landfill, and inert landfill. Municipal solid waste landfills allow non hazardous waste to be disposed of. The majority of waste found in these landfills are dumped from family homes, hotels or commercial industries. Also "common waste at these landfills are items we use and then throw away such as product packaging" [Conserve energy future, online, 12th September 2014]. Monitoring of these sites occur daily and all MSW (municipal solid waste) landfills must match and meet federal regulation. Construction and Demolition landfills provide a place to dispose of materials used or produced in construction renovation or demolition. Some common items found in these landfills are concrete, wood or glass. Construction and demolition landfills, like MSW landfills,are also non hazardous. Inert landfills make home for disposal of materials such as concrete, asphalt rock and other earth like products. The uncommon hazardous waste landfills are mainly managed in America. Hazardous waste is defined as being "waste that poses a threat to public health or the environment" [Learn about landfills, Online 12th September 2014]
Parts of a landfill
There are five main parts to a permitted and safe landfill.
- A bottom liner is the part that acts as a cover to stop the buried waste from coming in contact and polluting water or soil below. This is constructed of plastic.
- Cells are the actual area where waste is being disposed. New cells are used everyday and vary in size depending on the amount of waste.
- Covering is an important part of the landfill process. Covering is where waste in the cell is covered by around 6 inches of soil daily. Alternatives to this are spray on covers and tarp covers. Whenever a area of the landfill is used it is firstly covered with plastic then a layer of compacted soil before finally a layer of topsoil. There are many benefits to covering some being the prevention of pests and the topsoil used helps vegetation growth, preventing erosion.
- Collection systems. There are three main by-products of landfill. Leachate, methane gas and toxins. Leachate is water inside the landfill that is passing through all the rubbish heading towards a sump at the bottom of the landfill where it will be caught and removed for treatment at a facility elsewhere. A lack of oxygen in the soil allows bacteria to break down the trash causing landfill gas to be produced which is fifty percent methane. Methane can be collected and burned under controlled conditions
- The final 'key' part of a landfill is groundwater monitoring stations. Stations are used for testing the accessible groundwater. The station tests whether the water contains any leachate chemicals or toxins. Stations are found on upper and lower areas of the landfill, the upper being used to test water before it moves through the trash and the lower testing the water when it has finished passing through the trash.