APPLICATION OF ADVANCE STATISTICAL TECHNIQUES (DESIGN OF EXPERIMENTS) TO WATER TREATMENT PROCESS

Abstract

A well-defined experimental plan is essential for achieving the study goals and for an efficient use of the available resources. The aim of this article is to introduce the experimenter to the Design of Experiments (DoE) methodology by emphasizing the importance of an accurate data collection for a comprehensive understanding of the process and to avoid unnecessary waste of the resources. A brief description of the DoE method and a comparison with the traditional method (OVAT – One Variable At a Time) is hereafter provided. Furthermore, two case-studies where the DoE methodology has been applied are also reported: the first one concerns the influence of five inorganic compounds on the consumption of peracetic acid (PAA), a strong oxidizing agent that has been drawing increasing attention in wastewater treatment for its good properties as disinfectant; while, the second one is related to the optimization of a H2O2/UV advanced oxidation process to maximize the decolorization yield of a tertiary treatment for municipal and textile wastewater. In both situations the DoE methodology was effective: in the first case it enabled discovering and understanding how the interaction between two inorganic compounds significantly affects the PAA consumption – this would not be possible using the conventional OVAT method; whereas, in the second case very similar results to the ones obtained with the OVAT method were achieved but with a substantial reduction in the use of resources.