Digestão anaeróbia do lodo biológico de uma ETE petroquímica – um estudo de caso
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Data
2019-05-31
Autores
Orientador
Konrad, Odorico
Banca
Feil, Alexandre
Bücker, Francielle
Ferla, Noeli Juarez
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Resumo
A energia das biomassas é oriunda do tratamento de dejetos orgânicos que pode ser feito através da digestão anaeróbia, que gera o biogás. Através de biodigestores, que nada mais são do que reatores anaeróbios, onde o material orgânico que pode ser esgoto, efluente, lodo de ETEs e demais resíduos com elevada carga orgânica, é decomposto por bactérias metanogênicas. No tratamento de efluentes em ETEs Petroquímicas é gerado o lodo biológico, que se trata da biomassa que se formou às custas do alimento fornecido pelo efluente. O lodo biológico pode conter substâncias que conferem periculosidade ao resíduo como poluentes orgânicos persistentes, metais pesados e micro- organismos patogênicos que podem classificá-lo como perigoso. O objetivo do trabalho foi realizar a digestão anaeróbia do lodo biológico proveniente de uma ETE Petroquímica para quantificar e qualificar o biogás gerado e verificar a concentração dos contaminantes presentes após a digestão. A metodologia utilizada foi a realização da digestão anaeróbia do lodo em escala laboratorial, as análises físico-químicas e a caracterização do lodo conforme ABNT NBR 10.004/2004 antes e após a digestão. Os resultados dos experimentos mostraram um baixo rendimento na produção de biogás e de metano com PBB de 45,13 mL Biogás/gSV, PBM de 25,9 mL Metano/gSV e com rendimento estimado de 0,7235 m3 de metano por tonelada de lodo. Os percentuais médios de metano obtidos nos experimentos foram de 33,2 %, 50,95 % e 39,17 %. Para os experimentos contínuos, percebeu-se a redução dos percentuais de metano durante as alimentações com o lodo e o aumento destes percentuais após término das alimentações, demonstrando a presença de agentes inibidores de produção de metano nesse substrato. A caracterização do lodo evidenciou altas concentrações de Cromo, que conferem característica tóxica ao lodo e que é considerado um agente inibidor da produção de biogás, por se tratar de um metal pesado. O cromo é de origem de lixiviados de aterros sanitários que são tratados juntamente com os efluentes petroquímicos. Concluiu-se que o lodo após ser submetido a digestão anaeróbia não apresentou produção de biogás e metano satisfatória para aproveitamento energético na ETE devido aos agentes inibidores presentes e ainda que não houve alteração na classificação de resíduo após a digestão, permanecendo o lodo caracterizado como resíduo perigoso pela presença do cromo em sua composição.
The biomass energy comes from the treatment of organic waste that can be done through anaerobic digestion, which generates biogas. Through biodigestors, which are nothing more than anaerobic reactors, where the organic material that can be sewage, effluent, sludge from TEEs and other wastes with high organic load, is decomposed by methanogenic bacteria. In the treatment of effluents in Petrochemical ETE is generated the biological sludge, which is the biomass that was formed at the expense of the food provided by the effluent. Biological sludge may contain hazardous substances to the waste such as persistent organic pollutants, heavy metals and pathogenic microorganisms that may qualify as hazardous. The objective of this work was to perform the anaerobic digestion of the biological sludge from a TEE Petrochemical to quantify and qualify the generated biogas and verify the concentration of the contaminants present after the digestion. The methodology used was the anaerobic digestion of the sludge in laboratory scale, the physical-chemical analyzes and the characterization of the sludge according to ABNT NBR 10,004 / 2004 before and after digestion. The results of the experiments showed a low yield in the biogas and methane production with PBB of 45.13 mL Biogas/gSV, PBM of 25.9 mL Methane/gSV and with an estimated yield of 0.7235 m3 of methane per ton of sludge. The average percentages of methane obtained in the experiments were 33.2 %, 50.95 % and 39.17 %. For the continuous experiments, it was noticed the reduction of the percentages during the feeds with the sludge and the increase of these percentages after finishing the feeds, demonstrating the presence of agents inhibiting methane production in this substrate. The characterization of the sludge showed high concentrations of Chromium, which confer a toxic characteristic to the sludge and that is considered an agent inhibiting the production of biogas, because it is a heavy metal. Chromium is the source of leachate from landfills that are treated together with petrochemical effluents. It was concluded that the sludge after being submitted to anaerobic digestion did not present biogas and methane production satisfactory for energy use in the ETE due to the inhibitory agents present and although there was no change in the classification of the residue after the digestion, remaining the sludge characterized as residue dangerous by the presence of chromium in its composition.
The biomass energy comes from the treatment of organic waste that can be done through anaerobic digestion, which generates biogas. Through biodigestors, which are nothing more than anaerobic reactors, where the organic material that can be sewage, effluent, sludge from TEEs and other wastes with high organic load, is decomposed by methanogenic bacteria. In the treatment of effluents in Petrochemical ETE is generated the biological sludge, which is the biomass that was formed at the expense of the food provided by the effluent. Biological sludge may contain hazardous substances to the waste such as persistent organic pollutants, heavy metals and pathogenic microorganisms that may qualify as hazardous. The objective of this work was to perform the anaerobic digestion of the biological sludge from a TEE Petrochemical to quantify and qualify the generated biogas and verify the concentration of the contaminants present after the digestion. The methodology used was the anaerobic digestion of the sludge in laboratory scale, the physical-chemical analyzes and the characterization of the sludge according to ABNT NBR 10,004 / 2004 before and after digestion. The results of the experiments showed a low yield in the biogas and methane production with PBB of 45.13 mL Biogas/gSV, PBM of 25.9 mL Methane/gSV and with an estimated yield of 0.7235 m3 of methane per ton of sludge. The average percentages of methane obtained in the experiments were 33.2 %, 50.95 % and 39.17 %. For the continuous experiments, it was noticed the reduction of the percentages during the feeds with the sludge and the increase of these percentages after finishing the feeds, demonstrating the presence of agents inhibiting methane production in this substrate. The characterization of the sludge showed high concentrations of Chromium, which confer a toxic characteristic to the sludge and that is considered an agent inhibiting the production of biogas, because it is a heavy metal. Chromium is the source of leachate from landfills that are treated together with petrochemical effluents. It was concluded that the sludge after being submitted to anaerobic digestion did not present biogas and methane production satisfactory for energy use in the ETE due to the inhibitory agents present and although there was no change in the classification of the residue after the digestion, remaining the sludge characterized as residue dangerous by the presence of chromium in its composition.
Descrição
Palavras-chave
Energias renováveis; Biogás; Lodo biológico; Periculosidade de resíduos; Agentes inibitórios; Renewable energies; Biological sludge; Hazardous waste; Inhibitory agents
Citação
MAFIOLETI, Joseane Parizzi. Digestão anaeróbia do lodo biológico de uma ETE petroquímica – um estudo de caso. 2019. Dissertação (Mestrado) – Curso de Sistemas Ambientais Sustentáveis, Universidade do Vale do Taquari - Univates, Lajeado, 26 jun. 2019. Disponível em: http://hdl.handle.net/10737/3467.