Pollution control and biodiesel production with microalgae: new perspectives on the use of flat panel photobioreactors regarding variation in volume application rate

• Published in: Environmental science and pollution research international 2024-10, Vol.31 (49), p.58973-58987
• Main Authors: de Mello Mattos, Cecília, dos Santos, Mônica Silva, Santana, Jacob, de Carvalho, Daniel Fonseca, Massache, Assamo, Zonta, Everaldo, Boas, Renata Vilas, Lucchetti, Leonardo, Mendes, Marisa, de Mendonça, Henrique Vieira
• Format: Article
• Language: English
• Subjects: Algae; Anaerobic processes; Animal wastes; Animals; Aquatic microorganisms; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biodiesel fuels; Biofuels; Biomass; Bioremediation; Carbon dioxide; Carbon dioxide fixation; Carbon sequestration; Cattle; Cetane number; Chemical oxygen demand; Diesel; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Flat panels; Lipids; Microalgae; Nitrates; Nitrogen; Nutrient removal; Nutrients; Organic carbon; Photobioreactors; Pollutant removal; Pollutants; Pollution control; Research Article; Total organic carbon; Waste Water Technology; Wastewater; Water Management; Water Pollution Control
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-024-35024-9

In the present study, the microalga Arthrospira platensis DHR 20 was cultivated in vertical flat-plate photobioreactors (FPBRs) to bioremediate anaerobically digested cattle wastewater (ACWW) and used as a growth substrate. The final objective was to evaluate the properties of the oil extracted from this biomass to determine its potential for biodiesel production. The process was divided into five phases, varying the volume of the applied substrate: 1 L (Phase I), 5 L (Phase II), 10 L (Phase III), 15 L (Phase IV), and 20 L (Phase V). Dry biomass reached a maximum of 5.7 g L −1 , and productivity peaked at 0.74 g L −1 d −1 . The highest rate of CO 2 biofixation was 1213.5 mg L −1  day −1 , showing good potential for purifying the air. The highest specific maximum growth rate (μ max ) and the shortest doubling time (Dt) were found during Phase I. The removal of pollutants and nutrients during the experimental phases ranged from 65.8% to 87.1% for chemical oxygen demand (COD), 82.2% to 85.8% for total organic carbon (TOC), 91% to 99% for phosphate (PO 4 3− ), 62.5% to 93% for nitrate (NO 3 − ), 90.4% to 99.7% for ammoniacal nitrogen (NH 4 + ), and 86.5% to 98.5% for total nitrogen (TN). The highest lipid production recorded was 0.172 g L −1  day −1 . The average cetane number recorded in Phase IV of 51 suggests that the fuel will ignite efficiently and consistently, providing smooth operation and potentially reducing pollutant emissions. The analysis of fatty acids revealed that the produced biodiesel has the potential to be used as an additive for other low-explosive biocombustibles, representing an innovative and sustainable approach that simultaneously offers bioremediation and carbon sequestration.