Feijoo et al. (2026) Insights into the environmental performance of nature-based wastewater technologies towards water and carbon neutrality

Identification

• Journal: Journal of Environmental Management
• Year: 2026
• Authors: Helena Feijoo, Sofía Estévez, Sara González‐García, Maria Inês Aguiar
• DOI: 10.1016/j.jenvman.2026.128657

Research Groups

• CRETUS (Cross-disciplinary Research in Environmental Technologies), Department of Chemical Engineering, Universidade de Santiago de Compostela, Spain.
• Experimental Centre for New Water Technologies (CENTA), Carrión de los Céspedes, Spain.

Short Summary

This study performs a comparative Life Cycle Assessment (LCA) of four biological wastewater treatment systems in the Iberian Peninsula to evaluate their environmental performance and progress toward water and carbon neutrality. The results demonstrate that nature-based solutions like constructed wetlands significantly lower the land area required for carbon offsetting compared to energy-intensive membrane-based technologies.

Objective

• To evaluate and compare the environmental impacts of four different wastewater treatment configurations (bio-filters, activated sludge, constructed wetlands, and membrane bioreactors) using a Life Cycle Assessment (LCA) framework.
• To quantify the potential of these technologies to achieve water and carbon neutrality in the context of agricultural irrigation.

Study Configuration

• Spatial Scale: Regional (Iberian Peninsula, including sites in Bragança, Portugal; Seville, Spain; and Barcelona, Spain).
• Temporal Scale: Operational inventory data for the year 2024; infrastructure impacts for constructed wetlands calculated over a 10-year lifespan.

Methodology and Data

• Models used: Life Cycle Assessment (LCA) conducted via SimaPro® V10.0.0.29; ReCiPe 2016 Midpoint (H) and Environmental Footprint (EF) 3.0 impact assessment methods.
• Data sources: Primary inventory data from four full-scale facilities (Alfândega da Fé, Mirandela, CENTA, and Gavà-Viladecans); Ecoinvent® V3.10 for background processes; IPCC 2006 and PRTR for emission factors.

Main Results

• Environmental Ranking: The bio-filter system (ALF) was the best-performing technology in 5 out of 8 impact categories, while the membrane bioreactor (GAVA) showed the worst performance due to high energy demand (0.51 kWh/m³).
• Climate Impact: Operational climate change impacts ranged from 0.098 kg CO2eq./m³ (ALF) to 0.58 kg CO2eq./m³ (CENTA).
• Water Neutrality: Only the ALF system achieved a positive water balance; its indirect water consumption (0.9 L/m³) was significantly lower than the volume of treated water produced.
• Carbon Neutrality: Constructed wetlands (CENTA) require approximately 0.79 ha of cropland to offset operational greenhouse gas emissions. In contrast, non-nature-based solutions require between 16.7 ha and 566.2 ha of cropland to achieve the same offset.
• Sensitivity: Freshwater eutrophication results were highly sensitive to the choice of characterization method (ReCiPe vs. EF 3.0), with differences up to 38% due to local characterization factors.

Contributions

• Provides a novel integration of standard LCA metrics with the specific strategic goals of water and carbon neutrality for wastewater treatment plants (WWTPs).
• Offers a quantitative comparison between nature-based solutions (NBS) and conventional high-technology systems using primary data from full-scale operational facilities.
• Establishes a benchmark for the land area required for carbon sequestration/offsetting across different wastewater treatment technology tiers.

Funding

• INTERREG SUDOE project 'Sustainable management of water resources in irrigated agriculture in the SUDOE area' (I-ReWater-S1/2.5/E0136).
• Spanish Ministry of Science, Innovation and Universities (MICIU/AEI/10.13039/501100011033) project TED2021-130309B-I00.
• European Union NextGenerationEU/PRTR.
• BIORECER project (No 101060684) funded by the European Commission HORIZON-CL6–2021-ZEROPOLLUTION-01.
• Galician Competitive Research Group (GRC ED431C 2025/19) and CRETUS Research Center (ED431G 2023/12).

Citation

@article{Feijoo2026Insights,
  author = {Feijoo, Helena and Estévez, Sofía and González‐García, Sara and Aguiar, Maria Inês},
  title = {Insights into the environmental performance of nature-based wastewater technologies towards water and carbon neutrality},
  journal = {Journal of Environmental Management},
  year = {2026},
  doi = {10.1016/j.jenvman.2026.128657},
  url = {https://doi.org/10.1016/j.jenvman.2026.128657}
}

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