Tratamiento de aguas residuales procedentes de la industria láctea por métodos de oxidación avanzada heterogéneos de Fenton, ozonización y foto-Fenton a escalas de laboratorio

Abstract

The dairy industry in Ecuador requires large quantities of water, which after the production process and when combined with chemical products necessary for cleaning, presents a drastic increase in organic matter, thus compromising conventional treatments; therefore, the application of advanced oxidation processes (AOPs), characterized by generating hydroxyl radicals (OH¬.) as oxidizing agents, which are responsible for oxidizing the organic matter in the wastewater, is efficient. The following investigation aims to determine the degree of contamination of an effluent from the dairy industry where milk-based products and by-products are produced. For the analysis, sampling is carried out at the same point on different days. The experimental phase consists of biological and chemical treatments to reduce the organic load and reach the maximum permissible discharge limits established by the environmental authority. The effluent is pre-treated to improve the efficiency of the AOPs. The sample is left to settle in Imhoff cones, then coagulation and flocculation is performed with aluminum polychloride, 2 min in fast mixing and 4 min in slow mixing, the sample is left to settle, and finally it is filtered. Two tests are carried out applying advanced oxidation processes in different order. In test 1, the following processes were used: Fenton, biological treatment, ozonation and UV light, obtaining an efficiency of 97.3% in the reduction of COD; while in test 2, the following processes were used: anaerobic treatment, biological treatment, Fenton, ozonation and UV, obtaining an efficiency of 98.6% in the reduction of COD, with both tests having the expected results that comply with current environmental regulations.