Estudo da aplicação do resíduo de decantador de ETA como auxiliar de floculação no tratamento de água

• Ano de defesa: 2011
• Autor(a) principal: SOUZA, Leonora Milagre de
• Orientador(a): SCALIZE, Paulo Sergio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Mestrado em Engenharia do Meio Ambiente
• Departamento: Engenharias
• País: BR
• Palavras-chave em Português: resíduo de ETA; gerenciamento; tratabilidade de resíduo; coagulante
• Palavras-chave em Inglês: residue of WTP; management; residue treatability; coagulant
• Área do conhecimento CNPq: CNPQ::ENGENHARIAS::ENGENHARIA SANITARIA::SANEAMENTO AMBIENTAL
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tde/617

The residue generated in Water Treatment Plant (WTP) are derived from different stages of water treatment, especially the discharge of decanters. The most common practice in Brazil is the residue disposal directly into rivers, causing negative impacts to the environment. In general, the WTP have difficulties in managing the residue because the high costs of transportation and disposal, the steady increase in the consumption of chemicals, among other complicating factors. Aiming to reduce the coagulant used in the process and improving the characteristics of the residues for the outflow, this research examined the effects of biosolids application decanter of WTP in the processes of coagulation, flocculation and sedimentation of water treatment. Through laboratory tests, using Jar Test, there were three series of tests, each one using gross water with distinct turbidity. In these trials were used differents dosages of aluminum sulfate and applied to WTP samples with different concentrations of total solids suspended (TSS). After the Jar Test, the decanted water was characterized as turbidity and color, solids and coliforms were not found significant changes in their quality. For most situations, the residue application in treatment has reduced the coagulant in the range 50% to 60%. The increased turbidity of gross water allowed the application of more concentrated residue without reducing the efficiency of treatment in terms of turbidity removal. Regarding the sedimented material in the Jar Test, the decreasing of the dosage of coagulant favored the reduction of the occupied volume by the material, independent of the concentration of residue applied. The specific resistance of sedimented material was higher when compared to the situation without the application in virtually all studied situations. For water with 100 NTU and implementation of residue greater than 7.500 mg/L, and water with 210 NTU and residue less than 8.600 mg/L there was improvement in the sedimentability. The dewatering ability of the sediments by centrifugation was also improved with the application of the residue with 3.642 mg/L and 75% of the coagulant, and 7.500 mg/L using 50% of coagulant. The chemical conditioning by nonionic polyelectrolyte did not improved in the dewatering of sedimented material, but in improving water quality supernatant. Based on this study it was noticed that the application of WTP residue in water treatment was satisfactory as for the analyzed parameters, considering the dosage of coagulant used and the residue applied.