Author(s): Silva, Thiago ; Pereira, Alexia Saleme Aona de Paula ; Ferreira, Jessica ; Lorentz, Juliana F. ; de Assis, Marilia Luise ; Assemany, Paula ; Reis, Alberto ; Calijuri, Maria Lucia
Date: 2024
Persistent ID: http://hdl.handle.net/10400.9/4302
Origin: Repositório do LNEG
Subject(s): Microalgae; Wastewater treatment; Biofilms; Domestic sewage; Hybrid systems
ABSTRACT: Recently, hybrid systems, such as those incorporating high-rate algal ponds (HRAPs) and biofilm reactors (BRs), have shown promise in treating domestic wastewater while cultivating microalgae. In this context, the objective of the present study was to determine an improved scraping frequency to maximize microalgae biomass productivity in a mix of industrial (fruit-based juice production) and domestic wastewater. The mix was set to balance the carbon/nitrogen ratio. The scraping strategy involved maintaining 1 cm wide stripes to retain an inoculum in the reactor. Three scraping frequencies (2, 4, and 6 days) were evaluated. The findings indicate that a scraping frequency of each 2 days provided the highest biomass productivity (18.75 g total volatile solids m(- 2) d(-1)). The species' behavior varied with frequency: Chlorella vulgaris was abundant at 6-day intervals, whereas Tetradesmus obliquus favored shorter intervals. Biomass from more frequent scraping demonstrated a higher lipid content (15.45%). Extrapolymeric substance production was also highest at the 2-day frequency. Concerning wastewater treatment, the system removed 93% of dissolved organic carbon and similar to 100% of ammoniacal nitrogen. Combining industrial and domestic wastewater sources to balance the carbon/nitrogen ratio enhanced treatment efficiency and biomass yield. This study highlights the potential of adjusting scraping frequencies in hybrid systems for improved wastewater treatment and microalgae production.
