Every day, human activity generates tonnes of waste: from the packaging we use to the rubble from building work on our street. In a world that is increasingly aware of its environmental impact, waste management has become a tool for reducing the amount of waste and making the most of materials.
However, not all waste is recyclable, which represents a significant challenge in the responsible management of these materials to protect both the environment and people’s health. Faced with this reality, controlled final disposal facilities, commonly known as landfills, have become a key solution, designed with innovative technology that allows for the safe management of non-recoverable waste.
These facilities, such as those managed by Urbaser, are equipped with advanced systems for waterproofing, leachate collection and gas recovery, guaranteeing a controlled and positive environmental impact, as well as contributing to long-term sustainability by reducing the ecological and social risks associated with final waste disposal.
A landfill is an infrastructure used to dispose of waste that cannot be recovered, depositing it underground or on the surface. Its role is to properly process this waste to avoid a negative impact on the environment and on people’s health. They are, in short, the last level in the waste hierarchy for the management of materials that cannot be recovered or used for energy. Landfills can be classified according to the type of waste they receive. These can be inert, non-hazardous or hazardous waste.
ADVANCED TECHNOLOGY
Landfills have an infrastructure designed and managed to protect citizens and the environment. Technology plays an essential role in each stage of the process and guarantees that waste is managed in a safe and sustainable way. From the outset, landfills are built with a series of measures to reduce their negative effects.
A natural or artificial impermeable geological barrier isolates the waste from the soil and groundwater to prevent contamination. Rainwater drainage systems are implemented to reduce the production of leachate, a toxic liquid that is generated when rain ‘washes’ the waste. Dams and embankments are created, and constructions to give stability to the landfill, which are monitored to detect displacements that affect the structure of the site.
The technology used during the process of unloading, spreading, compacting and covering waste has a direct impact on its efficiency and sustainability. The waste is unloaded into the landfill and spread with the help of machines designed specifically for this task. The compactors form uniform layers, which effectively reduces the volume occupied by the waste. In landfills, such as the one owned by Urbaser in Colmenar Viejo, the waste is compacted and interspersed with layers of sand to manage the volume efficiently.
Raquel Rodríguez Barrueco, manager of the Colmenar Viejo Packaging Sorting Plant, explains the importance of this technology: ‘The arrangement of these layers is fundamental to impede the passage of (clean) rainwater and separate it from (dirty) wastewater. The wastewater is channelled into retention ponds and then to the treatment plant, where they are transformed into clean water (permeate) and a concentrated waste that is sent to other treatment plants.”
Good compaction is important because it maximises the capacity of the landfill, reduces the generation of leachate and prolongs its life.
A key aspect of landfills is the biogas they produce, a mixture of gases generated during the decomposition of organic waste that can be harnessed to produce green energy. The biogas is collected by means of a system designed to capture it efficiently and prevent it from being released into the environment.
At the Colmenar Viejo plant, the biogas generated in the landfill is used to power engines that produce energy for the plant itself, increasing its sustainability, and to export to the electricity grid, offering electricity from renewable sources to other consumers.
Sealing is the final stage of a landfill, in which layers of mineral and synthetic materials are used to prevent the emission of methane and the generation of polluting leachates. ‘Depending on the type of material buried, the landfill can continue to generate gas for a certain period of time,’ explains Raquel Rodríguez. ‘When it stops emitting gas, a cap to prevent CO₂ emissions into the atmosphere.”
Sealed landfills have a monitoring system that controls their condition for a minimum of 30 years. Afterwards, the land can be reclaimed and used for other purposes. The systems used in landfills, together with additional technologies such as sensors to measure air quality, drones to assess gas emissions and tools to model their carbon footprint, represent an example of how technological innovation can contribute to sustainable waste management.
Landfills such as the one in Colmenar Viejo are necessary facilities to sustain a circular economy. However, it is possible to reduce their size and impact through recycling and responsible consumption. In this way, it is possible to reduce the amount of materials that are deposited in landfills and increase the amount of those that can have a second life, to contribute to the well-being of the planet and of people.
