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The impact of climate change is an increasingly tangible reality. Episodes of drought, torrential rains and floods are increasingly frequent in Spain, one of the countries most affected by the climate emergency.
This great challenge requires innovative solutions that allow us 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 is carrying out several actions that promote the transformation towards a circular model.
One of the company's strategic lines is to convert wastewater 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, 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 recovery 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 necessary to carry out its activity and give new life to waste that can be transformed into a resource. All this with a double objective: reduce the volume of waste managed and reduce the consumption of raw materials.
Aigües de Barcelona has reduced its greenhouse gas (GHG) emissions by more than 50% during the period 2015-2022, far exceeding the previously set objective, and with its sights set on climate neutrality before 2050. To advance in In this direction, the company is deploying several projects, such as energy efficiency, the implementation of solar panels and photovoltaic collection pergolas in its facilities, energy generation through sludge cogeneration and the electrification of the vehicle fleet.
Likewise, it promotes eco-efficiency in all stages of the integral water cycle and the valorization of sludge (a waste rich in organic matter) generated in ecofactories. In 2022, the company valued 100% of the sludge generated in the treatment plants it manages: 63% was used for composting, 33% for direct application to agriculture and 4% for external anaerobic digestion.
Reclaimed water is currently being pumped from the Baix Llobregat regeneration station upstream of the river to Molins de Rei to be reused as pre-drinking water. In this way, regenerated water is provided to the river so that the Sant Joan Despí water treatment plant can capture it downstream and treat it again to convert it into drinking water and follow the water cycle.
In a normal year, 95% of the water resources for the Barcelona metropolis are linked to climatology, that is, surface and groundwater, 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 groundwater (wells and aquifers), 33% to desalinated water and 25% to regenerated water. .
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 to achieve a circular economy through the generation of biomethane from biogas produced in the anaerobic digestion of sludge from the Baix Llobregat Ecofactory, to power a public bus in the metropolitan area of Barcelona. From the recovery of sludge waste generated at the Baix Llobregat Ecofactory, biomethane is produced with sufficient quality to be used as fuel in public transport.
