Optimization of UV/H₂O₂and ozone wastewater treatment by the experimental design methodology

Abstract

The objective of this study was to optimize UV/HO and ozonation systems by means of an experimental design using as a response the efficiency of the operational conditions to remove the methylene blue (MB) dye. Two classes of experimental planning were used: the Doehlert matrix (DM) and the central composite design (CCD). The most important variables for each process were hydrogen peroxide concentration, the ratio of illuminated volume/total volume of the reactor and recirculation flow rate for UV/HO, and ozone flow rate, consumed ozone and MB concentration for the ozonation. The DM was more efficient in optimizing the systems, since it used a smaller number of experiments and achieved similar results when compared to the CCD. After optimization, the disinfection efficiency of the systems was tested with secondary effluent evaluating the inactivation of microbiological indicators, Escherichia coli and total coliforms, using the optimized and the worst condition previously obtained with MB removal as response. The inactivation efficiencies in the optimum conditions were about 99%, allowing an efficient disinfection as well as the production of an effluent with quality to be reused according to specific legislations, while at the worse conditions, the inactivation did not reach standards for reuse.

Using BCN nanostructure as anode electrode for photoelectrocatalytic degradation of organics: a statistical approach

“…Different parameters as independent variables can have effects on pollutants removal from wastewaters as dependent variables (Malvestiti et al 2019). The optimization of the dependent variable is the goal of many studies so does ours.…”

Optimización del proceso sono-foto-Fenton para el tratamiento de aguas residuales usando un diseño central compuesto

“…Una baja concentración de iones ferrosos hace que la producción de HO• no sea tan alta, de modo que al aumentar la misma, lo hace también la cantidad de estas especies radicalarias producidas. Sin embargo, cuando la concentración de Fe 2+ es demasiado alta, puede suceder que a pesar de que se forme una alta cantidad de HO•, éstos se recombinan entre sí (ecuación 4), disminuyendo de este modo el poder de oxidación del sistema (Malvestiti, Fagnani, Simão, & Dantas, 2019 El modelo de regresión cuadrático utilizado permitió, de igual manera, analizar la influencia de cada uno de los factores considerados (pH de la solución de reacción y la concentración de agente promotor y oxidante) en el sistema de oxidación tomado como base. Si bien, se propone tener en cuenta otras variables de gran influencia en el poder de oxidación del mismo, tales como la frecuencia y la potencia a la que se generan las ondas de ultrasonido.…”

Elimination of DOC in RO concentrate from a wastewater reclamation plant: Cost comparison of different AOPs

“…S3), thereby more photons would be absorbed by H 2 O 2 that leads to higher production of ･OH to oxidize organic compounds in RO concentrate. DOC removal efficiency of the UV/H 2 O 2 process can be also improved by increasing UV lamp intensity [32]. However, increasing the H 2 O 2 concentration would be the most efficient way to improve the efficiency of the UV/H 2 O 2 process, considering that a dominant portion of energy cost is generally contributed by UV lamp output.…”