Adensamento de lodo de estação de tratamento de água (Leta): um estudo a partir do tratamento por floco-flotação do lodo gerado na estação de tratamento de água Presidente Castelo branco, Pernambuco-Brasil

Abstract

The present work aims to present the study, development of a project and tests of a pilot Effluent Treatment Station (ETEF), for the treatment of waste generated at the President Castelo Branco-PE treatment station. The study unit was a floc-flotter (FFAD), which combines flocculator technologies in trays followed by solvent air flotation (FAD), with the application of Polydadmac, a high-load polymer of low molecular weight. The study of the chemical conditioner Polydadmac had the function of a surface modifier. The water supplied for treatment at the Presidente Castelo Branco WTP has eutrophication problems, where the presence of algae in the waste generated makes it difficult to ingest the sludge water. Consequently, there is not a good performance in the consolidation and drainage stages, making the treatment inefficient. In Brazil, most WTPs throw their waste indiscriminately into water bodies. The curbing of this practice is evidenced through public policies of bodies such as the ANA (National Water and Basic Sanitation Agency National Water Agency), and existing laws in Brazil, such as the Environmental Crimes Law (Law 9.605/1998). Therefore, it is necessary to adapt sanitation systems in terms of treatment and proper disposal of waste produced by water treatment plants. For the reasons listed above, this research was developed with the aim of having an effective treatment for the LETA generated at the ETA Tapacurá / Presidente Castelo Branco, Recife-PE. In the pilot unit project, bench tests were carried out to determine the parameters applied in the project, such as. With the results in hand, the treatment unit was dimensioned to be applied in the sludge consolidation stage, where 6 tests were carried out in the pilot ETEF to evaluate the quality of the clarified and the quality of the floated sludge. The best results found had as variables: polymer dosage of 3 in g / kg SST, recirculation rate of 40%, gradient of 100 s-1, with removal of: turbidity 98%, color 99.03%, SST 99 .97%, 99.92% aluminum, 99.92% iron, 99.91% manganese, 97.44% COD 86.4% and BOD 95.62%. It is observed that in the application of polymer-modified microbubbles, the polymer-bubble-residue interactions coat and functionalize to generate positively charged microbubbles. The results showed that the combination of technologies (tray flocculator dissolved air flotation - FAD) with application of cationic polymer (Polydadmac), offered quality to the effluent, and adapted to the current legislation for standards of release in water bodies, for standards of release in water bodies, and also to the recommended standards for recirculation in the water treatment plant for human consumption. The densified residue also met the percentages required for the solids content in the floated sludge.