RT Journal Article
T1 Large-Scale Commercial-Grade Volatile Fatty Acids Production from Sewage Sludge and Food Waste: A Holistic Environmental Assessment
A1 Castro Fernández, Ander
A1 Estévez Rivadulla, Sofía
A1 Lema Rodicio, Juan Manuel
A1 Taboada Santos, Antón
A1 Feijoo Costa, Gumersindo
A1 Moreira Vilar, María Teresa
K1 Life cycle assessment
K1 Dark fermentation
K1 Sewage sludge
K1 Food waste
K1 Volatile fatty acids
AB The valorization of sewage sludge and food waste to produce energy and fertilizers is a well-stablished strategy within the circular economy. Despite the success of numerous laboratory-scale experiments in converting waste into high-value products such as volatile fatty acids (VFAs), large-scale implementation remains limited due to various technical and environmental challenges. Here, we evaluate the environmental performance of a hypothetical large-scale VFAs biorefinery located in Galicia, Spain, which integrates fermentation and purification processes to obtain commercial-grade VFAs based on primary data from pilot plant operations. We identify potential environmental hotspots, assess the influence of different feedstocks, and perform sensitivity analyses on critical factors like transportation distances and pH control methods, using life cycle assessment. Our findings reveal that, on a per-product basis, food waste provides superior environmental performance compared to sewage sludge, which, conversely, performs better when assessed per mass of waste valorized. This suggests that higher process productivity from more suitable wastes leads to lower environmental impacts but must be balanced against increased energy and chemical consumption, as food waste processing requires more electricity for pretreatment and solid-liquid separation. Further analysis reveals that the main operational impacts are chemical-related, primarily due to the use of NaOH for pH adjustment. Additionally, facility location is critical, potentially accounting for up to 99% of operational impacts due to transportation. Overall, our analysis demonstrates that the proposed VFAs biorefinery has a carbon footprint comparable to other bio-based technologies. However, enhancements in VFAs purification processes are necessary to fully replace petrochemical production. These findings highlight the potential of waste valorization into VFAs as a sustainable alternative, emphasizing the importance of process optimization and strategic facility placement.
PB Elsevier
SN 2666-4984
YR 2024
FD 2024-12-15
LK https://hdl.handle.net/10347/38733
UL https://hdl.handle.net/10347/38733
LA eng
NO Castro-Fernandez, A., Estévez, S., Lema, J.M.,  Taboada-Santos, A., Feijoo, G.,  Moreira, M.T., 2025. Large-scale commercial-grade volatile fatty acids production from sewage sludge and food waste: A holistic environmental assessment. Environmental Science and Ecotechnology, 23, 100518.
NO This research was supported by the European Union NextGenerationEU/PRTR, and the project Biological Resources Certifications Schemes (BIORECER), funded by the European Executive Agency under call HORIZON CL6-2021-ZEROPOLLUTION-01 (101060684). It was also carried out thanks to the INTERREG ECOVAL and CIGAT CIRCULAR projects, funded by Interreg Sudoe and the Xunta de Galicia and Viaqua, respectively. Estévez also thanks the Spanish Ministry of Science, Innovation and Universities for financial support (Grant reference PRE2020-092074). A. Castro, S. Estévez, J. M. Lema, G. Feijoo, and M.T. Moreira authors belong to the Galician Competitive Research Group (GRC ED431C 2021/37) and the Cross-disciplinary Research in Environmental Technologies (CRETUS Research Center, ED431E 2018/01).
DS Minerva
RD 24 abr 2026