Tratamento termofílico de efluentes de máquina de papel utilizando biorreator a membranas

• Ano de defesa: 2008
• Autor(a) principal: Sousa, Cláudio Arcanjo de
• Orientador(a): Silva, Cláudio Mudado
• Banca de defesa: Rezende, Ana Augusta Passos , Passos, Flávia Maria Lopes , Aquino, Sérgio Francisco de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Ciência Florestal
• Departamento: Manejo Florestal; Meio Ambiente e Conservação da Natureza; Silvicultura; Tecnologia e Utilização de
• País: BR
• Palavras-chave em Português: Biorreator a membrana; Tratamento termofílico de efluentes; Água branca; Lodo ativado
• Palavras-chave em Inglês: Membrane bioreactor; Thermophilic treatment of effluents; White water; Activated sludge
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::TECNOLOGIA E UTILIZACAO DE PRODUTOS FLORESTAIS
• Link de acesso: http://locus.ufv.br/handle/123456789/521

Paper mill industrial processes consume large quantities of water consequently leading to large mill effluent volumes. One way to reduce water consumption is by increasing water reuse in the paper mill. Direct water reuse is not always possible because of poor effluent quality and effluent treatment may be necessary to permit reuse. Membrane bioreactors are a new treatment technology that are little used, mainly due to the lack of scientific and technical knowledge of their implementation. The present study examined the technical viability of thermophilic treatment of paper machine effluents in a membrane bioreactor. The studied was divided into three experiments. The main objective of the first experiment was to compare performance of laboratory-scale conventional activated sludge (CAS) and a membrane bioreactor (MBR) with 0,02µm porosity membranes in treating printing and writing paper machine white water at 35, 45 and 55°C. Results showed that the BRM was more efficient that the CAS in removing part of the effluent contaminant load. Average percent removals of chemistry oxygen demand (COD) in the CAS were 70.0, 78.1 and 76.7% and in the MBR 81.4, 81.9 and 78.7% at temperatures of 35, 45 and 55°C, respectively. Treated effluent total suspend solids (TSS) values in the CAS were 39, 54 and 88 mg.L-1 at of 35, 45 and 55°C. No TSS were detected in the MBR treated effluent. Turbidities of effluents treated in the CAS were 16, 35 and 165 NTU at temperatures 35, 45 and 55°C. MBR treated effluent presented no turbidity. Alkalinity and hardness of effluent treated by CAS were lower than for effluent treated by the MBR. The main objective of Experiment II was to compare performance of MBR effluent treatment under mesophilic (35°C), thermotolerant (45°C) and thermophilic (55°C) conditions. In Experiment II an MBR system composed of three reactors operating in parallel at the three different temperatures were used. This experiment was divided into three stages, with different COD loads in each: Stage 1 2.57 Kg.m-3.d-1; Stage II 4.75 Kg.m-3.d-1 and Stage III 9.43 Kg.m-3.d-1. The results showed that the increase in temperature led to reduction in COD removal efficiencies. Removals of COD in Stage I were 95.5, 94.2 and 91.9%, at temperatures of 35, 45 e 55°C, respectively. In Stage II, removal efficiencies were 97.4, 95.6 and 95.0% at 35, 45 and 55°C, respectively. In Stage II, removal efficiencies were 95.6, 93.3 and 89.7% at 35, 45 and 55°C, respectively. No TSS were detected in any of the treated effluents. Treated effluent turbidity increased with increased treatment temperature. Average turbidity of treated effluents were 0.11, 0.24 and 1.13 NTU in Stage I, 0.10, 0.16 and 1.01 NTU in Stage II and 0.87, 2.00 and 4.34 NTU in Stage III for treatment at 35, 45 e 55°C, respectively. Average conductivities of treated effluents were 1812, 1937 and 2927 µS.cm-1 for Stages I, II and III, respectively. Treated effluent color was greater for treatment at 55°C. Average color was 23, 23 and 102 mg.L-1 Pt in Stage I, 31, 36 and 127 mg.L-1 Pt in Stage II and 46, 58 and 163 mg. L-1 Pt in Stage III for temperatures of 35, 45 and 55°C, respectively. Average hardness values in treated effluents were 258, 203 and 160 mg.L-1 in Stage I, 439, 350 and 292 mg.L-1 in Stage II and 639, 565 and 495 mg.L-1 in Stage III, for treatments at 35, 45 and 55°C. No filamentous bacteria were found at 55°C and flocculation was deficient. The main objective of Experiment III was to evaluate sludge microbial diversity in aerobic MBRs operating under mesophilic and thermophilic conditions. It was found that increased temperature reduced reactor sludge microbial diversity and richness. A new microbial community was established above 45°C that differed structurally from the community present in the MBR operated at 35°C.