A novel membrane-based process to concentrate nutrients from sidestreams of an Urban Wastewater Treatment Plant through captured carbon dioxide from biogas

• Published in: The Science of the total environment Vol. 931; p. 172884
• Main Authors: González-Arias, Judith, Baena-Moreno, Francisco M., Rodríguez-Galán, Mónica, Navarrete, Benito, Vilches-Arenas, Luis F.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 25-06-2024
• Subjects: Biogas upgrading; Circular economy; CO2 utilization; Membranes; Nutrients concentration; Wastewater treatment plants; Membranes; Biogas upgrading; CO2 utilization; Nutrients concentration; Circular economy; Wastewater treatment plants; CO utilization
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.172884

Among the challenges that wastewater treatment plants face in the path towards sustainability, reducing CO2 emissions and decrease the amount of waste highlight. Within these wastes, those that can cause eutrophication, such as nutrients (nitrogen and phosphorous) are of great concern. Herein we study a novel process to concentrate nutrients via membrane technology. In particular, we propose the use of forward osmosis, applying the carbonated solvent which contains the CO2 captured from the biogas stream as draw solution. This carbonated solvent has a high potential osmotic pressure, which can be used in forward osmosis to concentrate the nutrients stream. To this end, we present the results of an experimental plan specifically designed and performed to evaluate two main parameters: (1) nutrients concentration; and (2) water recovery. The process designed involves pH adjustment, membrane filtration to separate solids, pH reduction and forward osmosis concentration of nutrients. With this process, concentrations factor for nutrients in between 2 and 2.5 and water recovery of approximately 50 % with water flux of 7 to 8 L/(m2h) can be achieved.
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•Formulation of an innovative membrane-based process to concentrate nutrients.•The process involves pH adjustment, membrane filtration, and forward osmosis.•We obtain concentrations factor for nutrients in between 2 and 2.5.•Water recovery of approximately 50 % with water flux of 7 to 8 L/(m2h) can be achieved.