Bio-factories in Greater Santiago (Chile)

Circular and resilient water management in urban areas

agosto 2025

ICLEI-Local Governments for Sustainability

Greater Santiago, the capital of Chile, has a population of over 6 million and faces major challenges in terms of water management: water stress, wastewater pollution and pressure on natural resources. With a Mediterranean climate (dry summers, rainy winters), the city must find sustainable solutions to secure its water supply and reduce its environmental footprint. With rapid economic growth and dense urbanisation, Santiago also faces problems relating to pollution and waste management, requiring innovative approaches to a circular economy.

The Greater Santiago bio-plants, managed by the Municipal Sanitation Works Company (EMOS), transform wastewater into valuable resources: clean water, energy and agricultural by-products. This innovative project demonstrates how a megacity can close the water cycle by making the most of every drop, whilst reducing its carbon footprint and creating new economic opportunities. The aim is to treat 100 per cent of the city’s wastewater by 2030, whilst producing renewable energy and supplying recycled water for non-potable uses.

Solutions implemented

• Bio-plants : Advanced treatment plants that combine biological processes (anaerobic digestion, sludge treatment) to produce recycled water, biogas and organic fertilisers.

• Biogas production : The methane captured during the anaerobic digestion of sludge is used to generate electricity, thereby reducing dependence on fossil fuels.

• Reuse of recycled water : The treated water is used for irrigating green spaces, industrial processes and other non-potable uses, thereby reducing pressure on freshwater resources.

• By-product recovery : Treated sludge is converted into organic fertiliser for agriculture, thereby creating a circular economy.

Key results

• Production of 100,000 m³/day of recycled water, reducing pressure on freshwater resources and supporting the city’s non-potable water needs.

• Generation of 20 MW of electricity from biogas, powering the bio-plants and thereby reducing dependence on the national electricity grid.

• A 30 per cent reduction in CO₂ emissions associated with wastewater treatment, thanks to the use of biogas and process optimisation.

• Creation of local jobs in the water, energy and agriculture sectors, thereby contributing to the region’s economic development.

Climate and environmental impacts

• Climate change mitigation :

  - The production of biogas from wastewater reduces dependence on fossil fuels, thereby lowering CO₂ emissions.

  - The reuse of recycled water reduces the need to pump and treat fresh water, an energy-intensive process.

  - Bio-plants operate with reduced energy consumption, thanks to the use of biological processes and biogas.

• Climate adaptation and resilience :

  - Water security : The production of reclaimed water improves the availability of water for non-potable uses, thereby reducing the city’s vulnerability to water shortages.

  - Wastewater management : Centralised and efficient wastewater treatment reduces the risk of pollution to watercourses and groundwater.

• Biodiversity and water quality : Reducing discharges of untreated wastewater improves the quality of aquatic ecosystems, thereby protecting biodiversity and public health.

Success factors

• Values :

  - Recognition of the multiple value of wastewater (water, energy, nutrients).

  - Integration of sustainability and the circular economy into resource management.

• Connections :

  - Physical connections : The bio-plants are integrated into the urban network, creating a coherent system for water and energy management.

  - Social connections : Collaboration between EMOS, local authorities, businesses and residents to design solutions tailored to the city’s needs.

Investments :

• Public funding : The project has received significant government support as part of national policies on sustainable water management.

• Public-private partnerships : Collaboration with local businesses to optimise resource management and recovery.

Referencias

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