What is a Landfill?

Have you ever wondered what happens to your waste when it is picked up by a trash truck?

Most individuals use the “out of sight, out of mind” attitude when it comes to trash disposal. When the garbage truck comes to pick it up or the roll-off dumpster is removed from your driveway, you aren’t normally thinking about where it will go.

Americans produce garbage at an astounding rate of 4.9 pounds (2.2 kilograms) per person daily, totaling 292.4 million tons (265.3 million metric tons) each year. According to a 2019 analysis by research company Verisk Maplecroft, Americans create about three times the global average for garbage.

What happens to all of this garbage? Some are recycled or salvaged, others are burnt, but most are dumped in landfills. This article will examine how landfills are constructed, what happens to waste in landfills, and the various available types.

What is a Landfill? 

A landfill is where waste is disposed of on the ground directly (land raising) or by filling an unintentional hole in the ground (landfilling).

Most modern landfills are designed and operated as solid waste disposal sites. Landfills are situated, developed, managed, and monitored to ensure strict laws and regulations are followed.

They are also built to safeguard the environment from toxins in the waste stream and feature on-site environmental monitoring systems. These systems are put in place to look for signs of groundwater pollution and landfill gas and provide further protection.

How do Landfills work?

Modern landfills are sealed to prevent groundwater pollution. The ground is first lined with clay. The clay layer is covered with a thin layer of flexible plastic. This facilitates the collection of leachate, a liquid that flows through a landfill and may extract pollutants from the waste.

The leachate is collected by a drainage system, which transports the polluted water through pipes to a pool, where it is treated to eliminate toxins before being discharged back into the environment.

Trash is compressed into a densely packed mound as it is added to the rising pile. To prevent smells and rodent concerns, a layer of earth is hauled over the rubbish daily. As a result, the landfill is largely composed of compacted layers of rubbish and dirt.

Another layer of clay and thin plastic is used to seal a completed landfill. The earth covers it for many feet, so plants may grow on top. Although landfills are just intended to hold waste, some of it will disintegrate over time.

Methane, a hazardous and combustible gas, is produced during the breakdown process. In modern landfills, methane is captured in pipes so that it may be released, burned, or even used as an energy source.

SEE: What Is A Septic System And How Does It Work? 

Parts of a Landfill

Landfill

Modern landfills aren’t all the same in terms of design, but they all use comparable technologies, even though the specific sequence and kinds of materials utilized vary from location to location.

Each component is intended to solve a distinct issue in a landfill. Here is the list of the various parts and their function.

Bottom Liner System

One of the most difficult issues for a landfill is to keep the waste container so that it does not cause environmental concerns. The bottom liner, which is composed of thick plastic, keeps waste from contacting the outside earth, particularly groundwater. 

Cells

To make the most use of the landfill’s amount of space, trash is compressed by heavy machinery into regions called cells, which generally store a day’s worth of refuse. After constructing the cell, it is filled with 6 inches (15 cm) of earth and compacted further.

Stormwater Drainage

A landfill features a storm drainage system that directs runoff into drainage canals and away from the buried rubbish. Other components of the system include plastic, concrete, or metal culverts beneath neighboring roadways and drainage basins, which can reduce suspended particles in the water to prevent soil loss from the landfill.

Plastic pipes and storm liners gather rainwater and send it to drainage ditches around the landfill’s foundation. The ditches are paved with concrete or gravel and channel water to gathering ponds on the landfill’s side.

Residual soil particles are allowed to settle in the collecting ponds, and the water is screened for leachate chemicals. Once the water has settled and passed testing, it is pumped or permitted to flow off-site.

Leachate Collection System

There is no ideal mechanism to prevent water from entering the waste, so water enters the landfill. Water percolates through the landfill’s cells and soil in the same way as water seeps through coffee grounds in a drip coffee maker.

Water gathers up pollutants when it trickles through the debris. This contaminated water is known as leachate, and it is often acidic.

Perforated pipes are installed throughout the landfill to collect leachate. These pipes are then connected to a leachate pipe, which transports it to a leachate collection pond.

Methane Collection System

Because the landfill is sealed, bacteria break down the rubbish without oxygen (anaerobic). Landfill gas, a consequence of this anaerobic decomposition, includes roughly 50% methane and 50% carbon dioxide, with trace quantities of oxygen and nitrogen.

Methane is a severe problem for landfills because it is a powerful greenhouse gas that traps heat in the atmosphere 28 to 36 times more efficiently than carbon dioxide. In addition, landfills are the third-largest source of methane emissions in the United States, accounting for approximately 15% of the gas released into the atmosphere in 2019. Methane is also a possible safety threat since it can explode and burn.

Covering or Cap

Putting down a layer of compacted earth covers the garbage from the atmosphere and keeps pests (birds, mice, rats, flying insects, and so on) out. To aid with rainwater drainage, waste at New York’s Fresh Kills Landfill is covered with at least 2 feet (0.61 meters) of dirt graded between 4 and 33 percent.

This layer is followed by extra layers of woven fibers, plastic, and a layer of soil to allow plants to grow on top of the landfill.

Groundwater Monitoring

Groundwater monitoring stations may be found everywhere around the site. These are pipelines lowered into the groundwater to sample and test the water for the concentration of leachate chemicals.

The groundwater temperature is also measured. Because groundwater temperature rises when solid waste breaks down, a rise in groundwater temperature may indicate that leachate is leaking into the groundwater. Additionally, if the pH of the groundwater grows acidic, it might signal leachate leakage.

SEE: What Is A Trash Compactor? 

What Types of Landfills Are There?

1. Municipal Solid Waste Landfills

If you dump it in the trash, it will be in a municipal waste (MSW) landfill. When you think of a landfill, this usually comes to mind. However, because they’re the most popular type does not mean they are accessible to the general population.

MSW landfills have one of the tightest safety and monitoring rules since they handle most domestic waste, ranging from used tissues to cardboard boxes from a garage cleanout. These regulations frequently include limits on site, landfill liners, operational operations, groundwater monitoring, and closure procedures.

3. Hazardous Waste Landfills

For obvious reasons, hazardous waste landfills are the most strictly controlled and constructed landfills. They are especially intended to contain hazardous waste in a way that almost precludes the possibility of its discharge into the environment.

Aside from these architectural criteria, hazardous waste dumps are frequently inspected numerous times per year to ensure that the facility is up to standard and that the standards are high.

If you’re worried that you could be trying to discard a restricted object, you can rest assured that it would be quite challenging for you to do so. Hazardous garbage is not collected curbside and is only permitted in dumpsters with advanced notice – and even then, very seldom.

2. Industrial Waste Landfills

If it appears that this landfill is self-explanatorily, it is. A landfill for industrial waste is a location where industrial waste is disposed of. While these landfills may accept any form of solid industrial waste, they are most typically used for construction waste disposal. That is why they are also known as C & D landfills.

Items often brought to industrial landfills include:

  • Concrete
  • Asphalt
  • Lumber
  • Metal
  • Gypsum
  • Bricks

4. Green Waste Landfills

While they are not officially approved landfills by the EPA, several towns are beginning to provide a location for organic debris to degrade organic.

Since most conventional landfills and collection points are less receptive to organic waste such as fruits, vegetables, and yard trash disposal, the number of composting facilities is increasing.

Some will accept yard garbage at a greater fee than others, but not all transfer stations will take it. This is entirely up to your local municipality.

Common types of green waste include:

  • Mulch
  • Leaves
  • Weeds
  • Tree branches
  • Flowers and grass trimmings
  • Biodegradable food waste

SEE: What is Dumpster Diving?

Drastic Effects of Landfills

Air pollution and its consequences

Landfills release more than 10 harmful gases, the most dangerous of which is methane gas. Methane gas is created spontaneously during the decomposition of organic substances.

According to the EPA, methane emitted during organic matter decomposition in uncontrolled landfills has the ability to trap solar radiation 20 times more effectively than carbon dioxide.

As a result, urban and global temperatures are rising. Aside from methane gas, various household and agrochemicals that end up in landfills, such as bleach and ammonia, can emit poisonous gases that negatively influence the air quality near the dump.

Dust, particle matter, and other non-chemical contaminants can also be released into the environment, adding to the problem of poor air quality.

Pollution of groundwater

The main environmental issue caused by landfills is groundwater pollution from leaches. Several hazardous pollutants find their way into landfills, and once there, the natural degradation of groundwater is unavoidable.

Industrial solvents to home cleansers are among the harmful materials found in landfills. Electronic trash and toxins from home and industrial items contain lead, cadmium, and mercury.

Health Effects

Numerous studies have found an increase in the likelihood of serious health consequences such as birth abnormalities, low birth weight, and certain malignancies among those who live near landfills. TCE, for example, is a carcinogen that is frequently found in landfill leachate. Other unpleasant and self-reported symptoms for those living near landfills include drowsiness, headaches, and weariness.

Pollution of the soil and land

Landfills make the soil and area where they are located unusable. Because the hazardous compounds spread across the surrounding soil over time, it also harms the neighboring soil and land area.

The soil’s top layer has been destroyed, reducing soil fertility, activity, and plant life. Industrial and electronic trash in landfills degrades soil and land quality, disrupting terrestrial ecosystems.

Costs to the economy

Landfill management has a substantial economic and social cost. In terms of integrated waste management, everything from managing landfill gases to groundwater contamination management and assuring compliance with environmental regulatory laws takes a lot of money from municipalities and taxpayers.

Because most items disposed of in landfills disintegrate over millions of years, developing successful waste management methods and infrastructure necessitates large capital investments in management and recycling programs.

Fires in landfills

When combined with a significant volume of landfill material, Landfill gases may easily ignite a fire. Once a fire has started, putting it out can be difficult, resulting in even more pollutants. If not controlled promptly, they can spread and damage nearby ecosystems.

Methane is the most flammable gas in the waste, and its abundance may cause havoc. The combustion of the waste exacerbates the issue by adding extra chemical load to the region.

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