Implementation of a Packed Bed Reactor With Mycological Silver Nanoparticles for Drinking Water Disinfection

Abstract

Basic sanitation and access to drinking water are critical challenges for developing countries. By 2025, water scarcity could affect 50% of the global population. Given this scenario, the search for sustainable and cost-effective water purification methods has driven research into the application of biologically synthesized silver nanoparticles (AgNPs). In this study, AgNPs were produced using the filamentous fungus Aspergillus niger IBCLP20 and encapsulated in calcium alginate (AgNP_IBCLP20/CA) for use in a packed-bed reactor (PBR) to treat water contaminated with Escherichia coli IPT245 and Pseudomonas aeruginosa IPT365. To evaluate the process parameters for water disinfection, the following variables were assessed: influent bacterial concentration (10³, 10⁴, and 10⁵ CFU·mL⁻¹), temperature (25°C, 30°C, 37°C, and 40°C), reactor occupancy (50%, 75%, and 100%), and volumetric feed flow rate (1.0, 4.0, 7.0, and 10.0 mL·min⁻¹). In the experiments, P. aeruginosa IPT365 exhibited greater resistance compared to E. coli IPT245. For both bacteria, the best antimicrobial results were obtained at an influent concentration of 10³ CFU·mL⁻¹. Temperature had no significant impact on the system for either of the bacterial strain. The antimicrobial activity against E. coli IPT245 was observed for all reactor occupancy levels tested, whereas the bactericidal effect against P. aeruginosa IPT365 was only achieved when the PBR was filled to 100% of the catalyst mass. The optimum volumetric flow rate was determined to be 4.0 mL·min⁻¹. These findings confirm that the PBR with encapsulated AgNP_IBCLP20/CA is a promising approach for water disinfection. The maintenance of antimicrobial activity after nanoparticle encapsulation, along with a detailed analysis of operational parameters, supports the feasibility of this method for environmental applications.