Determinação da toxicidade aguda e crônica de cloreto de sódio (NaCl) para a biomassa em sistemas de lodo ativado usando a respirometria como ferramenta de avaliação

• Ano de defesa: 2014
• Autor(a) principal: Oliveira, Samara Carolina Almeida de
• Orientador(a): Haandel, Adrianus Cornelius Van
• Banca de defesa: Alem Sobrinho, Pedro , Sousa, José Tavares de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual da Paraíba
• Programa de Pós-Graduação: Mestrado em Ciência e Tecnologia Ambiental - MCTA
• Departamento: Tecnologia Ambiental
• País: BR
• Palavras-chave em Português: Sistema de iodo; Cloreto de sódio; Respirometria
• Área do conhecimento CNPq: CNPQ::CIENCIAS HUMANAS::GEOGRAFIA
• Link de acesso: http://tede.bc.uepb.edu.br/tede/jspui/handle/tede/2001

Industrial effluents containing toxic substances such as salt, may interfere in the operation of activated sludge systems, causing death or inhibition of microorganisms. The effect of the toxicity of a substance can be classified as acute or chronic. Respirometry has been identified as an important tool for the evaluation of toxicity in biological systems, allowing to determine the kinetics of autotrophic and heterotrophic bacteria present in the system thus identifying the effect caused by toxic compounds. The objective of this study is to evaluate the toxicity of sodium chloride (NaCl) for microbial biomass of activated sludge systems using respirometry as an evaluation tool. To study acute and chronic toxicity of NaCl on biomass in activated sludge systems six concentrations of NaCl were studied : 10 , 15 , 22.5 , 33.75, 50.63 and 75.9 gNaCl / L. Two sequential batch reactors ( RBS 1 and RBS 2 )were operated under identical conditions. One reactor RBS1) was used as control reactor while the other (RBS 2) received increasing concentrations of NaCl for the study of chronic toxicity . RBS1 sludge was also used to perform acute toxicity tests The maximum specific growth rate of heterotrophic and autotrophic bacteria was adopted as a research parameter. The experimental results show that in both the chronic toxicity and acute toxicity tests, concentrations of 22.5 gNaCl / L reduced the potential growth of heterotrophic microorganisms by more than 50 % and a concentration of 15gNaCl/L completely inhibited activity of autotrophic organisms. In RBS 2 (chronic tests) the sludge adapted partially to high concentrations of NaCl , albeit with reduced activity. In acute tests, however, there was no biological metabolism when concentrations of 50 , 63 and 75.9 gNaCl/L were added. In general it can be concluded that the sludge can adapt at least partially to the continuous presence of high concentrations of NaCl in the influent, providing greater resistance to the presence of salt. The autotrophic organisms proved to be much more sensitive to the presence of the toxic material.