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9.7. Waste and its management

Solid waste

waste is any object, material or substance that is considered a waste because it has lost its usefulness and has to be disposed of. They occur after the exploitation, production and consumption of natural resources or by any human activity.
Although waste can be in liquid and gaseous state, in this topic we will focus on solid waste.

Types of solid waste

  • Solid urban waste. They are those generated in urban and domestic activities. They are very varied: paper, organic matter, plastics, glass, metal, containers, batteries, etc.
  • Agricultural, livestock and forestry waste. Generated by these activities: organic remains, fertilizers, pesticides, fertilizers, slurry, pruning remains, wood, sawdust, etc.
  • Sanitary waste. They are those from medical activities, produced by hospitals and laboratories, such as biological remains, syringes, medicines, gauze, X-rays, etc.
  • Industrial waste. Originating from industrial activities, they are very varied, such as oils, scrap metal, solvents, paints, acids, etc.
  • Radioactive waste. They come from nuclear power plants and from other places that use radioactive materials, such as hospitals and research laboratories. It is necessary to store them in very safe and protected places.

Each person in Spain generates an average of more than 400 kilos of waste per year that accumulates in landfills.

Solid waste problem

The main problem with solid waste is the large amount produced, since landfills collapse or, if incinerated, pollute the air. Additionally, rainwater can carry pollutants into nearby aquifers. They can also cause discomfort from the odors that are produced.

Hazardous waste has another problem, since it has to be stored in suitable landfills that are well sealed to avoid risks due to its toxicity.

If the waste has been abandoned in uncontrolled landfills, in addition to the visual impact it can contaminate the soil and water.

Solutions to the problem of solid waste

Society can act against the problem of solid waste by taking basic measures, commonly known as the "law of the three R's", which are:

  • Reduct. It is about reducing the amount of waste we produce. It is the most sustainable option to avoid the problem of waste. We can reduce waste by turning off the light when it is not necessary, using reusable bags when we do the shopping, avoiding unnecessary packaging, showering instead of bathing, etc.
  • Reuse. Before throwing away something that no longer serves us, we can think about how it can be used again. Thus we reduce the amount of waste. For example, reusing plastic bags or sheets of paper that are used for only one side.
  • Reciclar. If it cannot be reused again, these residues can be used to obtain other materials that are used again. For example, paper, metal, or glass can be recycled and have new uses, and are cheaper than non-recycled ones.

For these measures to be carried out, awareness campaigns and environmental education are necessary that, in addition to correct legislation, allow both industries and individuals to collaborate against this problem.

Solid waste impacts

The large amount of solid waste that is generated makes its elimination difficult, which is why it accumulates in the environment and generates some environmental impacts:

  • Soil contamination.
  • Contamination of aquifers by leachates.
  • Surface water pollution.
  • Air pollution if incinerated uncontrollably.
  • Visual impact spoiling the landscape.
  • Bad smell in the immediate vicinity.
  • Creation of infectious foci, if rodent and insect pests proliferate.

Sustainable management of solid waste

sustainable management of waste contributes to saving raw materials and the conservation of natural resources Waste management includes the collection, transport and treatment of waste:

Deposit and collection of waste

The waste deposits are made in containers, which are filled from 9 to 11 at night to avoid bad odors, and then they are collected by specialized vehicles. To facilitate recycling, we have several different containers in our cities, such as blue (paper and cardboard), green (glass) and yellow (plastic) in which we must deposit our previously classified waste at home. In addition, in some places there are also other containers for organic waste, batteries or used oil. For selective waste collection to take place, we must all collaborate and be aware of respect for the environment.

In addition, there are clean points (or green points) where neighbors can dispose of household waste that needs a specific type of recycling treatment and thus avoid polluting the environment. These clean points do not admit industrial waste and urban solid waste.

Contenedores para reciclar residuos en una calle

Some of the non-profit recycling companies that recycle waste in Spain are: Ecoembes (Ecoembalajes España SA)Ecovidrio (Ecological Society for the recycling of glass containers)SIGREEcopilas (Foundation for Environmental Battery Management)AmbilampEcolumECOLECECOTIC.

Waste transportation

The transport of waste is carried out in special trucks, to avoid inconvenience to the population, until they are taken to landfills and recycling plants.

Waste treatment

The waste treatment comprises all operations aimed at modifying biological physical, chemical or a residue to reduce or neutralize the hazardous substances containing recover usable resources, ease of use as an energy source or prepared for elimination.


The dumps are places where waste is finally deposited. There are several types of landfills:

  • Illegal landfills. Place where, without any control or environmental considerations, some people deposit their solid waste. They are sources of pollution, disease and other problems.
  • Controlled landfills. They are located in places far from the populations, on impermeable rocks (clays, for example) or waterproofed terrains. The waste is deposited in layers that are compacted and covered to reduce the visual impact and avoid bad odors. Gases are produced, such as methane, which can be used as a source of cogeneration of energy that can be used for the landfill itself.
  • Special landfills. Some wastes, due to their toxicity and danger, it is necessary to treat them to reduce their danger and deposit them in other special landfills, much more controlled to avoid risks.


The incineration of organic waste solids is a waste treatment system consisting of incinerating wastes at high temperatures, reducing its volume and 95% weight up to 80%. The ashes produced are toxic and must be taken to special landfills. The gases that are released contain polluting particles, such as dioxins from plastic combustion that are carcinogenic.

The energy generated in the combustion that takes place in the incinerators can be used to obtain electrical energy.


The compost is produced from organic waste from different origins are subjected to a process of fermentation called composting. Compost is a natural compost that can be used in agriculture and gardening.


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