Volume: 2, 2023
2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: E002
DOI: https://doi.org/10.24326/ICDSUPL2.E002
Published online: 19 April 2023
ICDSUPL, 2, E002 (2023)
Contaminants assessment of wastewater grown microalgae used as biofertilizer
Ana Álvarez-González1*, Enrica Uggetti1
1 GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya-BarcelonaTech, c/Jordi Girona 1-3, Building D1, E-08034 Barcelona, Spain
* Corresponding author: ana.alvarez.gonzalez@upc.edu
Abstract
To address the challenges posed by the increasing global population and contamination from conventional fertilizers, alternative to mineral fertilizers are needed. One promising option is nutrients recovery from wastewater, which supports a circular economy approach. In this context, microalgae-based systems are an alternative to traditional wastewater treatment methods, providing nutrient-rich microalgal biomass while reducing treatment costs and improving the sustainability of the process. This study examines the use of microalgal biomass grown in municipal wastewater as a biofertilizer in agriculture, specifically for basil and lettuce crops. The wastewater treatment process was effective, with removal efficiencies of 69%, 91%, and 81% for chemical oxygen demand, total inorganic nitrogen, and phosphates, respectively. The microalgal biomass, mainly composed of Scenedesmus, had a dry weight of 11% and nutrient concentrations of 7.6% nitrogen, 1.6% phosphorus, and 0.9% potassium. Greenhouse assays of both crops showed that the combination of microalgae and mineral fertilizer provided similar results as mineral fertilizer alone, allowing for a 50% reduction in mineral fertilizer dosage. The microalgal biomass was found to be safe for use as a biofertilizer, with low levels of pathogens and heavy metals, except for cadmium, which exceeded the European regulation threshold. CECs were present in wastewater, but only three out of 29 compounds were found in the microalgal biomass used as a biofertilizer. Cadmium and CECs were also found in lettuce samples from control treatments. This suggests that the presence of those contaminants might not be due to the application of microalgal biomass. The study concludes that combining microalgae grown in wastewater with mineral fertilizer is a promising source of safe nutrients for basil and lettuce crops, contributing to the circular bioeconomy.
How to cite
A. Álvarez-González, E. Uggetti, 2023. Contaminants assessment of wastewater grown microalgae used as biofertilizer. In: 2nd International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL2.E002