Reúso industrial de efluentes da indústria de óleo de soja em torres de resfriamento e caldeiras: revisão bibliográfica sobre a aplicação da flotação por ar dissolvido, ultrafiltração e osmose reversa

Abstract

The growing demand for water and the recurrence of water scarcity periods have heightened the need for alternatives to reduce the industrial dependence on natural water sources. In this context, this study evaluated the technical feasibility of water reuse from soybean oil processing effluents using an integrated treatment system composed of dissolved air flotation, ultrafiltration, and reverse osmosis. A qualitative, exploratory, and descriptive literature review was conducted drawing on scientific articles, books, dissertations and theses, regulations, and technical publications concerning effluent treatment and industrial water reuse. The characteristics of soybean processing effluents were analyzed, particularly from the refining stage, which may contain high concentrations of organic loads, oils and grease, suspended solids, colloidal particles, and dissolved salts. Dissolved air flotation, combined with coagulation and flocculation, effectively removes oils and grease, turbidity, suspended solids, and part of the organic load. Ultrafiltration enhances this treatment by retaining fine particles, colloids, macromolecules, and microorganisms, producing a suitable feed stream for reverse osmosis, which removes dissolved salts, hardness, silica, and conductivity. The integrated system demonstrates technical potential for producing reclaimed water suitable for cooling towers and boiler feed systems. Nevertheless, its implementation requires careful evaluation of effluent characteristics, target quality standards, treatability tests, operational control, and site-specific economic and environmental feasibility.