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The impact of climate change is an increasingly tangible reality. Episodes of droughts, torrential rains and floods are becoming more frequent in Spain, one of the countries most affected by the climate emergency.
This great challenge requires innovative solutions to adapt and mitigate the effects of the climate crisis, promoting more resilient and sustainable city models. And the circular economy, a model in which the concept of waste disappears, stands as the backbone of these solutions.
Aware of this challenge, in Catalonia, one of the regions most affected by global warming, Aigües de Barcelona carries out various actions that promote the transformation towards a circular model.
One of the company's strategic lines is to convert waste water treatment plants into ecofactories, applying the principles of the circular economy. It is about achieving energy self-sufficient facilities that transform waste into new products and that, in this way, integrate into their social and natural environment.
Ecofactories are a model recognized by the United Nations as an outstanding project in the fight against climate change. They are wastewater treatment plants (WWTP) designed with sustainability criteria and based on the regeneration of water for different uses, the generation of renewable energy and the valorization of waste (such as sewage sludge, converted into fertilizer for agriculture).
In the metropolitan area of Barcelona, Aigües de Barcelona follows the same strategic line of optimizing all the resources needed to carry out its activity and give new life to waste that can be transformed into a resource. All together with a double objective: reduce the volume of waste managed and reduce the consumption of raw materials.
Aigües de Barcelona has reduced greenhouse gas (GHG) emissions by more than 50% during the period 2015-2022, far exceeding the target previously set, and with its sights set on climate neutrality before 2050. To advance in this direction, the company is deploying several projects, such as energy efficiency, the implementation of solar panels and photovoltaic capture pergolas in its facilities, the generation of energy through the cogeneration of sludge and electrification of the vehicle fleet.
It also promotes eco-efficiency at all stages of the integral water cycle and the valorization of sludge (a waste rich in organic matter) generated in eco-factories. In 2022, the company valued 100% of the sludge generated in the treatment plants it manages: 63% was used for composting, 33% in direct application to agriculture and 4% in external anaerobic digestion.
Currently, regenerated water is pumped from the Baix Llobregat regeneration station upstream to Molins de Rei to be reused as potable water. In this way, regenerated water is brought to the river so that the Sant Joan Despí water treatment plant captures it downstream and treats it again to turn it into drinking water and continue the water cycle.
In a normal year, 95% of the water resources for the metropolis of Barcelona are linked to climatology, that is, surface and underground water, while 5% is desalinated seawater. In a drought situation like the current one, 19% of the water resource corresponds to surface water (mainly rivers), 23% to underground water (wells and aquifers), 33% to desalinated water and 25% to water regenerated
Another example of a circular model promoted by Aigües de Barcelona and Cetaqua, in collaboration with the Autonomous University of Barcelona and TMB, is the Life Nimbus. This European project, co-financed by the LIFE Program, aims at the circular economy through the generation of biomethane from the biogas produced in the anaerobic digestion of sludge from the Ecofactoria del Baix Llobregat, to power a public bus in the area metropolitan area of Barcelona. Based on the valorization of the sludge waste generated at the Ecofactoria del Baix Llobregat, biomethane is produced with sufficient quality to be used as fuel in public transport.
