MODELING AND SIMULATION OF CONTINUOUS ANAEROBIC REACTORS FOR ANTIBIOTIC REMOVAL IN SANITARY SEWAGE

Abstract

The use of antibiotics has increased in recent years due to population growth and the emergence of new diseases. However, the absorption of antibiotics is not complete, and up to 90% of the active compound can be excreted, which is absorbed by the soil and water, causing harmful effects to ecosystems. Sulfonamides and fluoroquinolones are widely used classes of antibiotics and have high persistence and low biodegradability, causing adverse effects such as the emergence of antibiotic-resistant genes and deregulation of DNA replication in aquatic organisms. These antibiotics are commonly found in hospital wastewater, which, without proper treatment in loco, enter the sewage collection systems and arrive at the sewage treatment plants (ETE) that, commonly, do not have efficient technologies in the removal of these drugs. Anaerobic reactors with immobilized biomass have been studied for the removal of antibiotics in sanitary sewage showing high efficiency in the removal of these compounds. However, further studies are needed in order to understand in detail the mechanisms of biodegradation of antibiotics in these reactors and enable the use of this technology to mitigate the environmental impacts caused by these compounds. In this sense, the present project aims to obtain mathematical models based on ADM1 that represent the anaerobic digestion of sanitary sewage and the degradation of antibiotics of the sulfonamide and fluoroquinolone classes in continuous anaerobic reactors with immobilized biomass. For this, modifications will be made in the structure of ADM1 to represent an anaerobic mixing reactor and immobilized biomass (complete mixing) and an anaerobic structured bed reactor (pistoned). The proposed models will go through steps of direct validation, sensitivity analysis and optimization of free parameters, statistical validation and cross-validation. In addition, the equations of the proposed models will be input to the COMSOL Multiphysics software for CFD simulation of these reactors.