In an era where the climate crisis reshapes the global resource economy, water emerges as the foundation of resilience and prosperity. Over three billion people live under water stress, and by 2050, global demand is expected to exceed available supply by more than half. In southern Europe, cities must reconcile economic vitality with climate adaptation, balancing growth and survival in a region increasingly defined by drought.
Córdoba, at the heart of the Guadalquivir basin, one of Spain’s most stressed and ecologically sensitive regions, has chosen to respond with vision and innovation. The La Golondrina Wastewater Treatment Plant, managed by EMACSA, becomes the epicenter of a new regenerative water economy. Once conceived merely to purify, it now regenerates. Once an endpoint of the urban cycle, it becomes a source. Through advanced treatment technologies and circular integration, the plant generates water, energy, and environmental value.
Originally inaugurated in 1991 as a pioneer of advanced treatment in Andalusia, La Golondrina is now a living symbol of transformation. Its modernization marks a shift from linear purification to circular regeneration, producing 3 hm³ of usable water each year, enough to meet the needs of more than 40,000 people or sustain 450 hectares of agricultural and urban green areas. Beyond these numbers lies its true value: each regenerated liter strengthens Córdoba’s water security and resilience across the Guadalquivir basin.
The project integrates innovation in filtration, UV disinfection, and membrane systems tailored to different reuse standards. It applies participatory governance and quantitative measurement through the Volumetric Water Benefit Accounting (VWBA 2.0) framework, ensuring additionality, traceability, and intentionality in every cubic meter of regenerated water.
Ultimately, La Golondrina demonstrates how urban infrastructure can evolve into an engine of territorial sustainability, reducing dependence on natural sources, improving water quality, and reinforcing climate resilience. Its measurable, replicable model supports Europe’s goals for reuse, circularity, and climate neutrality. Every regenerated liter becomes not only water returned to nature, but also a unit of resilience, employment, and shared hope, a Water Positive vision for Andalusia and the Mediterranean.
The Guadalquivir basin is a territory of contrasts: fertile yet fragile, historically abundant yet increasingly water-stressed. Climate variability and prolonged droughts jeopardize supply, agriculture, and biodiversity. Against this backdrop, the La Golondrina WWTP stands as a strategic response to one of Andalusia’s greatest environmental challenges.
By leveraging its existing biological treatment infrastructure, EMACSA propels La Golondrina toward regeneration through a tertiary line equipped with filtration, ultraviolet disinfection, and membrane technologies adjusted to target water quality. This configuration transforms over 3 hm³ of treated effluent annually into high-quality regenerated water, equivalent to the consumption of 40,000 households or the sustainable irrigation of 450 hectares.
The project produces tangible and measurable benefits:
These outcomes demonstrate how circular water solutions replace linear, resource-intensive models. The initiative also builds institutional collaboration: EMACSA operates the system; the Guadalquivir River Basin Authority and the Andalusian Government provide governance and regulatory support; and technological partners contribute innovation and monitoring capabilities.
This cooperative structure enhances both efficiency and scalability, making La Golondrina a replicable prototype for other European wastewater plants seeking alignment with emerging frameworks for reuse, decarbonization, and climate adaptation.
The timing is strategic. European Union regulations, including Regulation (EU) 2020/741, require cities to expand water reuse and reduce emissions from urban water systems by 2030. Projects like La Golondrina give institutions and companies a clear advantage: compliance with ESG criteria, access to green financing, and positioning as leaders in regenerative water management.
La Golondrina does not simply treat wastewater; it redefines what infrastructure can mean in a climate-constrained world, transforming it into a catalyst for regeneration, innovation, and shared value creation.
The project unfolds through progressive phases combining engineering, risk management, and continuous performance monitoring.
The project’s success lies in its adaptability to fluctuating hydrological conditions and its capacity to serve as a replicable solution for Mediterranean urban and agricultural systems under stress.
| SDG | Name | % Coverage | Depth | Technical Summary |
| 1 | No Poverty | 25.0% | 0.50 | Mentions green job generation and improvement of public health through access to non-potable water during droughts, linked to targets 1.4, 1.5, and 1.b. |
| 2 | Zero Hunger | 25.0% | 0.50 | Regenerated water enables sustainable irrigation of 450 ha, indirectly contributing to food security and agricultural resilience (2.3, 2.4). |
| 3 | Good Health and Well-being | 22.2% | 0.40 | Improves public health by reducing contaminants, disease risks, and ensuring alternative supply during water crises. Impacts targets 3.3, 3.9, 3.d. |
| 4 | Quality Education | 0.0% | 0.00 | No specific evidence in the described process. |
| 5 | Gender Equality | 0.0% | 0.00 | No specific evidence in the described process. |
| 6 | Clean Water and Sanitation | 85.7% | 0.93 | The project addresses 6.3, 6.4, 6.5, 6.6 through traceable actions of reuse, efficiency, participatory governance, and ecological restoration. |
| 7 | Affordable and Clean Energy | 20.0% | 0.70 | Biogas is recovered as a renewable source and achieves a 42% reduction in energy consumption, aligned with target 7.2. |
| 8 | Decent Work and Economic Growth | 27.3% | 0.50 | Creates skilled green jobs in operation and environmental management. Improves operational efficiency and reduces costs. Contributes to 8.2, 8.4, 8.5. |
| 9 | Industry, Innovation and Infrastructure | 33.3% | 0.70 | Implements advanced technologies (UV, membranes, SCADA), resilient infrastructure, and digital traceability. Applies to 9.1, 9.4, 9.5. |
| 10 | Reduced Inequalities | 0.0% | 0.00 | No specific evidence in the described process. |
| 11 | Sustainable Cities and Communities | 20.0% | 0.50 | Contributes to target 11.5 by strengthening urban water resilience against droughts. |
| 12 | Responsible Consumption and Production | 14.3% | 0.40 | Applies water circularity, effluent reduction, and energy optimization (12.2). |
| 13 | Climate Action | 33.3% | 0.70 | Mitigates emissions (1,200 tCO₂/year), reduces pressure on aquifers, and improves water adaptation (13.1, 13.2). |
| 14 | Life Below Water | 0.0% | 0.00 | No specific evidence in the described process. |
| 15 | Life on Land | 20.0% | 0.40 | Improves aquatic and ecological biodiversity of the Guadalquivir River (15.1). |
| 16 | Peace, Justice and Strong Institutions | 0.0% | 0.00 | No specific evidence in the described process. |
| 17 | Partnerships for the Goals | 20.0% | 0.25 | Multiple institutional, technological, and community actors participate (17.16). |
B) ANNEX OF TARGETS EVALUATED BY SDG
SDG 1 – No Poverty
1.4 – DIRECT-LOW – 0.50 – Equitable access to basic resources reinforced through non-potable supply during droughts.
1.5 – INDIRECT-HIGH – 0.40 – Reduction of climate vulnerability through resilient infrastructure against water stress.
1.b – INDIRECT-MEDIUM – 0.25 – Local participation and institutional cooperation as a framework for poverty reduction.
SDG 2 – Zero Hunger
2.3 – DIRECT-LOW – 0.50 – Indirect support for agricultural productivity with regenerated water for 450 ha.
2.4 – INDIRECT-HIGH – 0.40 – Water sustainability of agri-food systems in scarcity contexts.
SDG 3 – Good Health and Well-being
3.3 – INDIRECT-HIGH – 0.40 – Reduction of risks from waterborne diseases in regenerated water.
3.9 – DIRECT-MEDIUM – 0.70 – Decrease in pollutant load and exposure to effluents.
3.d – INDIRECT-MEDIUM – 0.25 – Improvement in health response capacity in water crises.
SDG 6 – Clean Water and Sanitation
6.3 – DIRECT-HIGH – 1.00 – Significant improvement in effluent quality and reduction of contaminants.
6.4 – DIRECT-HIGH – 1.00 – Reuse of 3 hm³/year reduces pressure on natural sources.
6.5 – INDIRECT-HIGH – 0.40 – Multi-actor cooperative governance with traceability (VWBA).
6.6 – DIRECT-HIGH – 1.00 – Ecological restoration of flows and aquatic biodiversity.
SDG 7 – Affordable and Clean Energy
7.2 – DIRECT-MEDIUM – 0.70 – Recovery of biogas as renewable energy and reduction of 42% in consumption.
SDG 8 – Decent Work and Economic Growth
8.2 – INDIRECT-MEDIUM – 0.25 – Increase in efficiency and operational productivity of the system.
8.4 – INDIRECT-HIGH – 0.40 – Efficient use of resources and water circularity.
8.5 – DIRECT-LOW – 0.50 – Creation of green jobs in operation and environmental management.
SDG 9 – Industry, Innovation and Infrastructure
9.1 – INDIRECT-HIGH – 0.40 – Urban infrastructure resilient to water stress.
9.4 – DIRECT-MEDIUM – 0.70 – Technological adaptation with SCADA, UV, and membranes.
9.5 – DIRECT-MEDIUM – 0.70 – Innovation in digital governance and VWBA metrics.
SDG 11 – Sustainable Cities and Communities
11.5 – DIRECT-LOW – 0.50 – Reduction of urban risks in extreme droughts.
SDG 12 – Responsible Consumption and Production
12.2 – INDIRECT-HIGH – 0.40 – Optimization of water, energy, and emissions resources.
SDG 13 – Climate Action
13.1 – DIRECT-MEDIUM – 0.70 – Local adaptation through reuse and water resilience.
13.2 – INDIRECT-HIGH – 0.40 – Contribution to climate plans and carbon neutrality (42% less CO₂).
SDG 15 – Life on Land
15.1 – INDIRECT-HIGH – 0.40 – Protection of aquatic biodiversity and ecological flows.
SDG 17 – Partnerships for the Goals
17.16 – INDIRECT-MEDIUM – 0.25 – Public–private–academic collaboration model.
C) DUAL CLASSIFICATION BY SDG (COVERAGE AND DEPTH)
| SDG | Coverage (%) | Depth | Combined Classification |
| SDG 1 | 25.0% | 0.38 | Medium–Medium |
| SDG 2 | 25.0% | 0.45 | High–High |
| SDG 3 | 22.2% | 0.45 | High–High |
| SDG 6 | 85.7% | 0.93 | High–High |
| SDG 7 | 20.0% | 0.70 | High–High |
| SDG 8 | 27.3% | 0.38 | Medium–Medium |
| SDG 9 | 33.3% | 0.60 | High–High |
| SDG 11 | 20.0% | 0.50 | High–High |
| SDG 12 | 14.3% | 0.40 | Low–Medium |
| SDG 13 | 33.3% | 0.55 | High–High |
| SDG 15 | 20.0% | 0.40 | High–High |
| SDG 17 | 20.0% | 0.25 | Medium–Medium |
| Others (4, 5, 10, 14, 16) | 0.0% | 0.00 | No evidence |
| Segment | Environmental | Social–Human Rights | Governance |
| Upstream | Neutral | Neutral | Neutral |
| Downstream | Positive – reduces pressure on aquifers and improves effluent quality | Positive – access to regenerated water and green jobs | Positive – multi-actor governance and traceability (VWBA) |
E) APPLICABLE RISK CHECKLIST
Environmental:
✓ Water scarcity
✓ Effluent contamination
✓ Biodiversity loss
✓ Over-extraction
Social / Human Rights:
✓ Public health (WASH)
Unequal access to water → not explicitly identified
Governance:
✓ Regulatory compliance
✓ Data transparency
✓ Due diligence (VWBA)
TECHNICAL RECOMMENDATIONS (for SDGs with <20% coverage)
SDG 4:
Incorporate educational modules on water reuse in collaboration with universities.
Offer professional technical training in operation of circular water systems.
SDG 5:
Ensure participation of women in project governance spaces.
Implement a gender perspective in hiring and training of green jobs.
SDG 10:
Identify vulnerable populations benefited and apply criteria for water equity.
Design distributive impact indicators for access to regenerated water.
SDG 14:
Monitor potential impacts on estuaries from improved effluent quality.
Include protection criteria for coastal ecosystems where applicable.
SDG 16:
Establish mechanisms for conflict resolution and open data transparency.
Strengthen accountability through public external audits.
FINAL METHODOLOGY
“Deterministic contribution methodology by coverage and depth (169 targets); water cross-cutting approach; UNDP SDG Impact standards; alignment with CSRD/ESRS/CSDDD.”
Version: 2.3 – Integrated Dual Score
AUTOMATIC CLOSURE
Total SDGs with relevant contributions without low levels:
→ 12 SDGs achieved
→ All with at least one Medium or High-level target
→ Excluded SDGs: 4, 5, 10, 14, 16
Implementation follows a transparent and verifiable sequence:
This phased structure ensures long-term permanence of benefits and compliance with evolving European standards for reuse, circular economy, and sustainable finance.
The La Golondrina WWTP – Reuse and Circular Energy Córdoba Project exemplifies how technology, governance, and nature can converge to regenerate urban water cycles. The intervention reuses treated effluent through a tailored combination of filtration, UV disinfection, and membrane systems, while capturing biogas from sludge to generate renewable energy. The result is a facility capable of treating 8,200 m³ daily and producing 3 hm³ of regenerated water annually, fully compliant with international and European quality standards.
By converting what was once discharged waste into a secure, traceable resource, the project reduces ecosystem pressure, strengthens water availability, and mitigates the risks of climate-driven scarcity. Improvements in effluent quality, over 95 percent BOD removal, 90 percent TSS, and 70 percent nitrate reduction, enhance aquatic biodiversity and reduce health hazards.
Strategically, La Golondrina consolidates Córdoba’s Water Positive roadmap, demonstrating measurable ESG performance through verifiable volumetric and qualitative indicators. It aligns with recognized frameworks for corporate water targets and with European sustainability reporting standards, fostering regulatory compliance, reputational value, and investor confidence.
Replicable in Mediterranean and semi-arid regions worldwide, its modular design, public-private governance, and digital backbone enable rapid adaptation to diverse contexts. The collaborative model, uniting EMACSA, the Guadalquivir River Basin Authority, the Andalusian Government, universities, and local communities, ensures institutional legitimacy and facilitates knowledge transfer.
Ultimately, the project enhances the Guadalquivir basin’s hydrological balance, reduces extractions from vulnerable aquifers, and strengthens resilience against extreme climatic events. Socially, it generates employment, protects health, and promotes equitable access to water. For companies and investors, it embodies how water innovation drives a regenerative economy, where every liter returned to the system represents a tangible, transparent commitment to the planet’s future.
