Investigação do uso de floculantes de fontes renováveis para o tratamento físico-químico de efluente industrial de processamento de milho

Abstract

Conventional wastewater treatment is commonly performed using inorganic coagulants such as aluminum sulfate or ferric chloride. However, the use of these compounds is associated with the potential development of health problems and generation of large sludge volume. Natural (organic) coagulants, abundantly available, can certainly be considered as an advantageous alternative in view of the disadvantages associated with the use of inorganic coagulants. In this research, it was investigated the use of cationic tannin as primary coagulant and cationic hemicellulose (HC) as coagulation aid, both obtained from renewable sources. And subsequently, anionic polyacrylamide (PAM-A) and cellulose acetate sulfate (SAC, as a sustainable alternative) for the dual-flocculation step during the physical chemical treatment of corn processing wastwater. Basically, the steps investigated on the jartest were: coagulation, flocculation and sedimentation. The results showed that, for this effluent, the tannin had greater effectiveness in removing turbidity at equalization pH equal to 11 and flocculation equal to 8, promoting the formation of stable expansive sludge by a inter-particle bridging mechanism. And, when associated with tannin (3T: 1HC solution), cationic hemicelluloses played an important role in reducing the volume of sludge generated (up to 21%), although it had no significant influence on turbidity removal. When the opposite charge polyelectrolyte (PAM-A or SAC) was added, the dual-flocculation mechanism removed turbidity above 99%. From the obtained results it was possible to conclude that the effluent treatment from corn processing industries can be performed using coagulants from renewable sources.