Photodynamic processes associated with anaerobic digestion of swine wastewater: removal of sulfamethazine and resistant bacteria

• Grant number: 24/13135-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: February 01, 2025
• End date: January 31, 2028
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: Marcelo Zaiat
• Grantee: Kamila Jessie Sammarro Silva
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 22/10615-1 - Consolidation of the biorefinery concept applied to the biological treatment of wastewater and solid wastes, AP.TEM

Abstract

The occurrence and spread of antibiotic resistance are a global problem, often originated in environments that highly rely on antimicrobials, including agriculture. This project, associatedwith the Thematic Project "Consolidation of the biorefinery concept applied to the biologicaltreatment of wastewater and solid waste" aims to enhance the anaerobic treatment of agroindustrial effluents by including an innovative physicochemical treatment stage. This project willconsider the veterinary antibiotic sulfamethazine (SMZ) used in pig farming, and we propose toevaluate the effects of integrating the photodynamic process with anaerobic digestion, which is the most used biological treatment technology for this type of effluent. Despite the efficiency of anaerobic biodigestion in upflow and sludge blanket reactors, the effective removal ofmicropollutants such as SMZ is still a challenge. Photodynamic treatment (PDT), i.e., the use of aphotosensitizer excited by light at a specific wavelength and in the presence of molecular oxygen, may be advantageous, a hypothesis based on the widespread use of PDT in clinical uses, vectorcontrol and water treatment. This project plan is primarily based on evaluating the efficiency ofPDT in inactivating resistant bacteria and removing SMZ from simulated swine farm wastewaterand real swine wastewater. In two consecutive work blocks, the performance associated with theinclusion of a PDT stage as pre- and another as post-treatment of a UASB reactor also treatingswine waste will be quantified. As for pre-treatment, a possible increase in biogas production will be assessed, along with the impacts on the ecology of the bioreactor's granular biomass and SMZ removal. In the case of post-treatment by PDT, reducing toxicological effects of the treated effluent is expected along with additional removal of SMZ by photodynamic action.