Caracterização da atividade biológica de efluente de polpa Kraft branqueada de eucalipto antes e após tratamento por lodos ativados e ozônio

• Ano de defesa: 2010
• Autor(a) principal: Lopes, Alessandra Cunha
• Orientador(a): Mounteer, Ann Honor
• Banca de defesa: Rezende, Ana Augusta Passos , Gomide, José Lívio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Engenharia Civil
• Departamento: Geotecnia; Saneamento ambiental
• País: BR
• Palavras-chave em Português: Efluente de polpa Kraft; Atividade biológica; Ozônio
• Palavras-chave em Inglês: Kraft pulp effluents; Biological activity; Ozone
• Área do conhecimento CNPq: CNPQ::ENGENHARIAS::ENGENHARIA SANITARIA::TRATAMENTO DE AGUAS DE ABASTECIMENTO E RESIDUARIAS
• Link de acesso: http://locus.ufv.br/handle/123456789/3727

The bleached eucalyptus kraft pulp industry, one of the most important sectors of the Brazilian economy, is responsible for generating large volumes of effluent that contains high organic loads, part of which is recalcitrant to conventional (biological) treatment. Studies with model ecosystems have indicated a direct correlation between organic matter remaining after biological treatment and biological activity of effluents in the aquatic environment, with toxicity and endocrine disruption being the main expressions of this biological activity in aquatic organisms present in receiving waters. The objective of the present study was to quantify the biological activity in beached kraft pulp mill effluent using acute and chronic toxicity and endocrine disruption assays and to evaluate the effect of ozonation on removal of the biological activity. To this end, primary and secondary effluents were collected at a Brazilian bleached kraft pulp mill. The secondary effluent underwent a toxicity identification evaluation and was treated with 50 mgO3 L-1. The primary and secondary effluents presented no acute toxicity to the microcrustacean Daphnia similis, but presented chronic toxicity towards the green alga Pseudokirchneriella subcapitata and the microcrustacean Ceriodaphnia dúbia. In general, chronic toxicity was reduced during biological treatment in the mill´s activated sludge effluent tretament plant, although the secondary effluent still presented chronic toxicity. Toxicity was higher in the high molar mass effluent fractions that contain the recalcitrant organic matter. On some collection dates, the effluent dilution necessary to eliminate the chronic toxicity effect was higher than the dilution occurring through effluent discharge to the receiving waters. The primary and secondary effluents also presented estrogenic activity, as quantified in the YES assay. Through the toxicity identification evaluation study, it was found that the recalcitrant organic matter, that includes residual lignin, extractives and their byproducts, is responsible for the estrogenic activity. Ozone treatment of the secondary effluent reduced its toxicity and estrogenic activity.