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Biohydrogen production from dairy industry wastewater in an anaerobic fluidized-bed reactor

Silva, Aline Neves da, Macêdo, Williane Vieira, Sakamoto, Isabel Kimiko, Pereyra, Daniela de Los Angeles Dalmao, Mendes, Camila Oliveira, Maintinguer, Sandra Imaculada, Caffaro Filho, Roberto Augusto, Damianovic, Marcia Helena Zamariolli, Varesche, Maria Bernadete Amancio, Amorim, Eduardo Lucena Cavalcante de
Biomass and bioenergy 2019 v.120 pp. 257-264
acetic acid, adhesion, biogas, biomass, dairy industry, ethanol, fermentation, fluidized beds, hydrogen, hydrogen production, industrial wastewater, metabolites, tires
The present study evaluated the influence of organic loading rate in biohydrogen production from dairy wastewater in an anaerobic fluidized-bed reactor inoculated by natural fermentation of the wastewater used during the operational period. The support material for biomass adhesion was shredded tire. The reactor had a working volume of 908.4 cm3. Biohydrogen production was evaluated using three different organic loading rates (OLR) of 28.7 kgCOD m−³d−1, 53.2 kgCOD m−³d−1 e 101,7 kgCOD m−³d−1 corresponding to the Hydraulic Retention Time (HRT) of 8 h (2.7 L d−1), 6 h (3.6 L d−1) and 4 h (5.4 L d−1), respectively. The hydrogen yield decreased with increasing organic loading rate (OLR) from 2.56 ± 0.62 mol H2 mol carbohydrate−1 to 0.95 ± 0.28 mol H2 mol carbohydrate−1 as the OLR increased from 28.65 kgCOD m−³d−1 to 95.76 kgCOD m−³d−1. The hydrogen content in the biogas (volume of H2/ volume of biogas) produced and the highest volumetric production were respectively 35.72 ± 9.43% and 0.80 ± 0.21 LH2 h−1 L−1 obtained when the OLR was 53.25 ± 7.81 kgCOD m−³d−1. The main metabolites produced were acetic acid (67.15%-87.42%) and ethanol (6.01%-13.09%). Increasing the applied OLR also caused an increase in bacterial diversity as evidenced by the highest value of the Shannon-Wiener index (2.811) corresponding to the operational phase of the highest OLR (95.76 ± 29.10 kgCOD m−³d−1).