Biodigestão anaeróbia de dejetos de bovinos leiteiros submetidos a diferentes tempos de exposição ao ar
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Data
2011-10-27
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Universidade Estadual Paulista (Unesp)
Resumo
Objetivou-se de avaliar a biodigestão anaeróbia e produção de biogás de dejetos de vacas leiteiras submetidos a diferentes tempos de exposição ao ar. Primeiramente foram coletados 300 kg de dejetos produzidos em 24 horas, que foram conduzidos ao pátio de armazenamento. A cada três dias, durante 18 dias, fazia-se o abastecimento dos biodigestores. Os biodigestores foram abastecidos com os dejetos provenientes da leira nos tempos de exposição zero (0d), três (3d), seis (6d), nove (9d), 12 (12d), 15 (15d) dias e 18 (18d) dias de exposição. A redução de massa foi avaliada em relação à matéria seca e à matéria natural do dejeto. A redução de massa da leira foi de 73 % em 18 dias. Os teores de ST dos tratamentos variaram de 17,8 % a 27,3 % e os teores de SV de 79,93 % a 73,8 %. O valor de pH variou de 7,38 a 9,24. Os picos de produção de biogás com elevado teor de CH4 foram mais adiantados quando os substratos foram obtidos nos maiores tempos de exposição, tornando evidente que uma fermentação prévia dos dejetos antes do abastecimento de biodigestores é conveniente para o adiantamento da produção de biogás. Em relação aos teores de metano, embora não se tenha observado diferença entre os tratamentos, houve diferença entre as semanas de leitura (P<0,05), em que nas quatro primeiras semanas os teores de metano foram menores do que os teores apresentados na quinta e na sexta semana. Houve diferença (P<0,05) entre os tratamentos para os potenciais de produção de biogás em relação aos ST adicionados, do estrume e dos substratos, sendo as melhores médias as dos tratamentos oriundos da leira após seis, nove e 12 dias de exposição
This study aimed to evaluate the anaerobic biodigestion and production of biogas from manure of dairy cows subjected to different times of exposure to air. First was collected 300 kg of waste produced within 24 hours, which were driven to the storage yard, and every three days, during 18 days, was made the supply of the biodigesters. The biodigesters were supplied with slurry from the pile in the exposure zero (0d), three (3d), six (6d), nine (9d), 12 (12d), 15 (15d) and day 18 (18d) days of the exposure. The reduction in mass was evaluated in terms of dry matter and matter's natural manure. The reduction in mass was 73% in 18 days. The levels of TS ranged from 17,8% to 27,3% and the levels of VS 79,93% to 73,8%. The pH ranged from 7,38 to 9,24. The peak production of biogas was earlier when the substrates were in the larger day, making clear that a prior fermentation of manure digesters before the supply is convenient for the advancement of biogas production. In relation to content of methane, but would not give significant difference between treatments was no significant difference between the days of reading (P <0.05), in which the first four readings of methane levels were lower than the levels presented in the fifth and sixth reading. Statistically significant (P <0.05) among treatments for the potential of ST added, manure and the substrate, and the best means of treatment from the following pile six, nine and 12 days of exposure
This study aimed to evaluate the anaerobic biodigestion and production of biogas from manure of dairy cows subjected to different times of exposure to air. First was collected 300 kg of waste produced within 24 hours, which were driven to the storage yard, and every three days, during 18 days, was made the supply of the biodigesters. The biodigesters were supplied with slurry from the pile in the exposure zero (0d), three (3d), six (6d), nine (9d), 12 (12d), 15 (15d) and day 18 (18d) days of the exposure. The reduction in mass was evaluated in terms of dry matter and matter's natural manure. The reduction in mass was 73% in 18 days. The levels of TS ranged from 17,8% to 27,3% and the levels of VS 79,93% to 73,8%. The pH ranged from 7,38 to 9,24. The peak production of biogas was earlier when the substrates were in the larger day, making clear that a prior fermentation of manure digesters before the supply is convenient for the advancement of biogas production. In relation to content of methane, but would not give significant difference between treatments was no significant difference between the days of reading (P <0.05), in which the first four readings of methane levels were lower than the levels presented in the fifth and sixth reading. Statistically significant (P <0.05) among treatments for the potential of ST added, manure and the substrate, and the best means of treatment from the following pile six, nine and 12 days of exposure
Descrição
Palavras-chave
Biogas, Bovino de leite, Biodigestor, Biodigestion, Biogas. eng
Como citar
MACHADO, Camila Romantini. Biodigestão anaeróbia de dejetos de bovinos leiteiros submetidos a diferentes tempos de exposição ao ar. 2011. vi, 51 f. Dissertação (mestrado) - Unviversidade Estadual Paulista, Faculdade de Ciências Agronômicas de Botucatu, 2011.