Abstract: The aim of this work was to perform a bench-scale evaluation of coagulation-flocculation, filtration and ozonation processes (each one separately and all combined) for the treatment of municipal wastewater for reuse in crop irrigation. Three coagulants (aluminum sulfate, ferric sulfate and aluminum polychloride), two stirring speeds and three pH values were evaluated. Three filter medias were used (silica sand, anthracite and mixed media bed) with four filtration speeds. For ozonation, a 23 experimental design was performed with two ozone gas concentrations (20 and 40 mg/l), two gas flows (30 and 60 L/h) and two contact times (15 and 30 min). The pollutants evaluated were treated as response variables. Ozone doses between 37 and 300 mg/l were applied. The most efficient coagulants were aluminum polychloride and aluminum sulfate. The best results were obtained with faster stirring speeds (278 G-S-1) for rapid mixing, and the coagulant doses were reduced (50-66%). Silica sand was the filter medium selected since it had the best efficiency. During the ozonation stage, statistical models were obtained to predict the reduction levels of the pollutants evaluated. A minimum dose of 40 mg/l is proposed. With the treatment scheme presented, reduction efficiencies of 84-98% were obtained for the physiochemical parameters and 99.98-100% for microbiological parameters, which enables complying with the norms for reuse in crop irrigation. | Resumen: El objetivo del trabajo fue la evaluación a escala de banco de los procesos de coagulación-floculación, filtración y ozonización (cada uno por separado y con la combinación de todos) en el tratamiento de agua residual municipal para su reutilización en riego agrícola. Se evaluaron tres coagulantes: sulfato de aluminio, sulfato férrico y policloruro de aluminio, dos gradientes de velocidad de agitación y tres valores de pH. Para la filtración se utilizaron tres medios filtrantes: arena sílice, antracita y lecho mixto, para cuatro velocidades de filtración. En la ozonización se realizó un diseño experimental 23 para dos concentración de ozono en el gas (20 y 40 mg/l), dos flujo de gas (30 y 60 l/h) y dos tiempos de contacto (15 y 30 min): como variable respuesta se consideraron los contaminantes evaluados, se aplicaron dosis de ozono entre 37 y 300 mg/l. Los coagulantes más eficientes fueron policloruro de aluminio y sulfato de aluminio. Se obtienen mejores resultados con el aumento de la velocidad de agitación en la mezcla rápida (278 G-S-1) y se reducen las dosis de coagulante (50-66%). Se seleccionó la arena sílice por su mejor eficiencia como medio filtrante. En la etapa de ozonización se obtuvieron modelos estadísticos para predecir los niveles de reducción de los contaminantes evaluados, se propone una dosis mínima de ozono de 40 mg/l. Con el esquema de tratamiento propuesto se logran eficiencias de reducción de los parámetros físico-químicos (84-98%) y microbiológicos (99.98-100%), que permiten cumplir con las normas para reutilización en riego agrícola.

This thesis addresses removal of Contaminants of Emerging Concern (CECs) from WWTP effluents, and evaluation of risks associated with their reuse in agriculture. Three treatment technologies were investigated for the removal of pharmaceuticals, including COVID-19 related compounds. The technologies encompass Solar/UV-LED photocatalysis, an Ozone system with Micro-Nano Bubbles (OMNB), and Granular Activated Carbon (GAC). MNBs greatly enhanced ozone's ability to remove CECs compared to traditional O3 methods. The best results were seen at a flow rate of 2000 L/h and 15.9 gO3/h. An initial assessment of the generated transformation products was presented. The CPC/UV-LED-TiO2 system, featuring a self-designed UV-LED, was more efficient than commercial lamps. The adsorbent MG1050, was implemented in a 3-module pilot prototype featuring disc-filtration, GAC bed adsorption, and UV disinfection. Outcomes were promising, with nearly 100% CEC elimination efficiencies in the regeneration system. An agronomic evaluation of effluent quality from different technologies assessed their impact on lettuce and carrot crops.