The increase in waste generation is a reality and landfills do not stop filling in them a mixture of different waste such as decomposition organic matter, leftovers of detergents, rest of oxidized liquids and metals, among others. This mixture causes a liquid by -product to be generated, called leachate, which are circulating through the rest of the waste. These leachates bring serious consequences, mainly because they cause contamination of channels and groundwater. That is why it is so necessary to reduce and recycle waste, in short, make good management of them to avoid leaching. In addition, it is also important to have methods to treat them.
If you want to know more about leachate and about the treatments used to control them, continue reading this interesting ecology article in which we talk about the definition of leachate, examples and their treatment.
What are leachate and leaching – definition
Leachate are the liquids that circulate between the waste that are found in the landfills. He leaching process occurs during processes of fermentation and decomposition of organic matter, as a consequence of the filtration of water from the rains that percolate between the waste and drag chemical compounds and biological materials. They are very polluting And a danger to the environment and the health of living beings, which is why they must be treated correctly.
The quality of these in a landfill depends on the time found in them and the type and amount of waste you have. For example, the quality of leachate of a developed country is not the same as one that is still in development, since, in developed countries, there is a Waste management (recycling) that prevents more volume of waste from reaching landfills. However, most developing countries do not have good waste management.
Leachate: examples
Did you know that worms produce a leachate rich in nutrients, also called Lombriz humuswhile decomposing organic matter? Yes, also thanks to its concentration in nutrients it is used as a fertilizer for crop. Although it is 100% natural and not toxic, it is composed of a large number of minerals and nutrients, so it is important to dilute it before use, since its high concentration that could be harmful to plants.
Therefore, mainly, as Examples of leachate We can distinguish between two types:
- The leachates of landfills: Liquids that circulate between landfill residues and are given by the leaching process when decomposition and fermentation occur.
- The leachates of the worms: liquids produced totally natural by these animals on Earth and the subsoil when feeding on organic matter and decomposing it.
Leachate treatment
All liquids with contaminating in the landfills must be treated before being discharged On a surface. In the treatment process, the characteristics of the leachate should be taken into account, as well as the location of the landfill. They do not receive the same treatment The leachates of a landfill new than those of a landfill that has been exploited for a long time, or those of an RNP landfill or hazardous waste. To perform treatment for Avoid contamination by leachateits characteristics must be taken into account, as well as the location of the landfill.
As we have mentioned before, leachates are stored in rafts before their final treatment, they differ depending on the type of landfill. The hazardous waste landfills (RP) They are deposited in rafts that must be waterproofed with polyethylene to avoid leaks, leachates of Non -hazardous waste landfills (RNP) They are collected in concrete rafts.
The Technologies to treat leachate are the following:
Thermal treatment (evaporation)
In this, the energy of the biogas that is generated in the landfill to evaporate leachates is used. This technology controls leachate emissions and, finally, there is a mud that is deposited again in the landfill. Here you can learn more about what evaporation is.
Biological
They can opt for aerobic or anaerobic treatments, depending on the characteristics of leachate. Aerobic biological treatments consist of using microorganism in the presence of oxygen and agitation, to purify the organic compounds present in leachate. On the other hand, the anaerobic process has the same principle, although microorganisms are in conditions characterized by the lack of oxygen.
Membrane systems
Technology using membranes is used more and more frequently, and is being included for leachate treatment. The applications that occur are the following: Ultrafiltration, reverse osmosis, microfiltration, nanofiltration and direct osmosis.
Physical-chemical treatments
This treatment eliminates coagulant particles, that is, metal salts and polyhelectrolytes. Coagulation, flocculation and sedimentation processes are involved. The treatments are classified as chemical precipitation, reverse osmosis, NH3 stripping, chemical oxidation and active carbon absorption.
Natural systems
Some systems that can work naturally, such as lagoons or wetlands, are proposed for leachate management, as an alternative to other treatments, and placing them where necessary artificially so that they then work naturally. However, with these systems a large number of territory for processes are required.
Learn more about leachates and their contamination with this other ecology article in which we talk about garbage pollution: causes and consequences.
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- Korena, MJ, 2008. Trade systems for leachate generated in sanitary landfills. Deepening line Integral solid waste management.
