Metro South Transfer Station

There is an interesting type of landfill, inert landfills. This type of landfill receives sand, concrete, and other waste related to construction. This type of waste does not have any biohazards nor decomposes, or it does so very slowly. These types of waste neither produce liquid waste. In this category, we mostly have asphalt, rocks, bricks, yard leaves. In this category, we do not include demolition waste.

Sanitary landfills offer a more advanced waste management approach that further reduces the chances of environmental contamination. The basic unit of a sanitary landfill is still the cell. The idea is to create soil tranches. The garbage is deposited onto layers 1 to 3 meters high and then compacted by bulldozers to reduce the volume. Then the garbage is covered by a layer of dirt. Multiple of these layers are piled together until they reach maximum capacity and thus, we form a cell. The cell is then reinforced on all sides to prevent leakage to the soil.

A landfill is a location that manages our waste. In some landfills the garbage is left in piles, in some the garbage is incinerated and, in some others, the waste is decomposed onto other chemical structures and processed. In some landfills, the waste is buried.

Landfills are in specific areas, and they are away from cities and counties as there are gases that leak from the decomposition of the waste. There are various types of landfills. Some are used for municipal waste, some are used for sorting of the waste, some serve as transfer stations, and some are specialized only for recycling. Each landfill has its acceptance conditions, which means only a specific type of waste can be accepted.

When a load of waste is accepted, the garbage trucks go to the dumping point and offload the materials. During the processing of the waste, the main ideas are to confine the waste in the smallest space possible and to reduce the volume of the waste by compacting it. The garbage trucks are weighed when they enter and exit the landfill. The difference is the tons of garbage deposited and that affects the cost to use the landfill. Each landfill has its prices per ton depending on the type of waste that is deposited.

There is a lot of waste generated in the USA. In 2018, there were 292 million tons of waste generated. Averagely that is 4.9 Lb. of waste per person. The waste from municipalities is recycled the most. The data says that in 2018, there was a recycling rate of 32%. Some of the waste is reprocessed not other means such as bio-chemical management.The largest categories of waste pertain to paper, food plastics, yard trims, and metals. Food, plastics, and paper make are the main resources for energy production from waste.

A landfill has very detailed business operations. The waste arrives at the facility in garbage trucks on a section called the Cell. The cell is made of an isolated layer, that prevents any waste or liquids from leaking. In the cell, the waste is sorted out. This unit is enclosed, as the sun and the atmospheric conditions can interact with the waste. Afterward, the garbage is compressed in the smallest volume possible. The cell will accept new waste until it is full. When it reaches, it is further reinforced on top with various materials and dirt. The idea is that the area on top of the cell is reused and to support vegetation.

The important part of this process is the base of the cell. It must prevent liquids and other pollutants from reaching the soil. For this reason, the cell is isolated below with layers of plastic and clay, to create a strong isolation system.

Regarding liquids, they are collected onto a unit called the sump. In this unit, the liquids are processed, and when they are cleaned on pollutants, they are reintroduced onto the environment. Each landfill has groundwater monitoring, which means they collect the quality of groundwater before it reaches the landfill and afterward it exits the landfill. Regarding gasses generated by the waste, they are collected via a special system that ends up reusing the methane generated and the gases to produce energy.

When a landfill reaches the point that all the cells are full, then the landfill stops operations. This doesn’t mean that the owners of the landfill have no responsibilities. They must be monitored for 30 years after closure, and that means assuring the quality of groundwater and preventing leakage to the soil of any type of waste.