Landfills
Landfills are government-regulated institutions that treat and monitor waste. Whereas dumps are unregulated places where waste is left unattended, a major risk to the environment in the sense that it can possibly contaminate groundwater, disrupt wildlife and the risk of natural disasters increase. Illegal dumping takes a stroll on the community as well, not just the environment. It leads to increased health issues and drops the value of properties around the dump.
Landfill Types
Industrial Waste Landfills. Often referred to as C&D landfills, these are landfills where construction debris is taken. They often work as material recovery facilities since items brought to them include concrete, lumber, asphalt, gypsum, metal, bricks, and building components. Items brought to the industrial waste landfills are sorted by the workers in search of reusable materials. Reusable materials are then either sold or donated to resellers. Items can be repurposed in the facility as well, for example, some facilities take lumber and break it into mulch.
- Hazardous Waste Landfills
Hazardous waste is defined as waste that has properties that make it dangerous for the environment and public health19.In comparison with regular landfills, hazardous landfills follow a stricter set of rules that ensures the disposal of toxic materials. Their anatomy is different from MSW landfills. Hazardous landfills require a double leachate collection system, leak detection, and so on. To read more on the anatomy of hazardous waste landfills.
Additionally, these landfills are inspected more to keep the standards as desired.
- Green Waste Landfills
Although green waste landfills are not sanctioned by the EPA, some municipalities are offering citizens a place for organic waste to decompose. Most of the landfills or transfer stations do not accept organic waste such as fruits, vegetables, or yard waste. Other common types of organic waste are mulch, weeds, leaves, tree branches., biodegradable food waste, flowers, and grass trimmings. These landfills serve the purpose of other landfills to save space from things that can decompose on their own. Important to note that this is rarely the case and green waste can end up at any landfill. Often people have their own compost in their gardens.
- Municipal Solid Waste Landfills
Waste has to decompose safely to minimize its effects on the community and environment. In today’s sanitary landfills, a layered design of waste treatment shifts the perception of old landfills. Although waste produces methane while decomposing, most landfills collect this gas and channel it to generate electricity.
Image Courtesy of OC Waste & Recycling
About MSW Landfills
The composition of a landfill is as follows.
1st Layer, The Liner System
The first layer is the foundation of the sanitary landfill. A compact and dense clay is splayed to prevent any sort of leakage that can contaminate groundwater. To reinforce the impervious clay, high-density plastic is layered on top of the clay.
2nd Layer, The Drainage System
During decomposition, waste can produce liquid, known as leachate. To prevent leachate from reaching the first layer, perforated pipes are used on top of the first layer to collect them. The collected leachate is then channeled to treatment facilities.
3rd Layer, The Gas Collection System
The decomposition of waste leads to methane production. Although the release of methane gas is dangerous for the environment, and a contributor to global warming, it is also the key element of natural gas. Through the 3rd layer, landfills are collecting methane through gas extraction wells that transport it to treatment areas and then to plants where it is processed into electricity or another form of valuable energy.
4th Layer, Thrash
The largest layer of the system is the topmost layer. Thrash is brought by various garbage companies to the facility and dumped onto the 4th layer. To make the most out of the limited space, the garbage is compressed. After the compression, a layer of soil is used to prevent the bad odor and the growth of flies and pests.
What happens when there is no longer space in the landfill?
Although it takes years for a landfill to get filled, once this happens a process called landfill capping is done. The filled landfill is capped with synthetic plastic or clay, similar to the first layer. The aim is to turn the landfill into a space that can be used for something else, as well as protect the environment from the bad odor and methane gas release. Old, capped landfills can be turned into various things such as parks or solar energy centers.