Abstract

This study assessed the effects of hydraulic retention time (HRT; 8 h–0.25 h) on simultaneous hydrogen and methane production from cheese whey (5000 mg carbohydrates/L) in a mesophilic (30 °C) expanded granular sludge bed (EGSB) reactor. Methane production was observed at HRTs from 4 to 0.25 h. The maximum methane yield (9.8 ± 1.9 mL CH₄/g COD_ap, reported as milliliter CH₄ per gram of COD applied) and methane production rate (461 ± 75 mL CH₄/day L_reactor) occurred at HRTs of 4 h and 2 h, respectively. Hydrogen production increased as methane production decreased with decreasing HRT from 8 to 0.25 h. The maximum hydrogen yield of 3.2 ± 0.3 mL H₂/g COD_ap (reported as mL H₂ per gram of COD applied) and hydrogen production rate of 1951 ± 171 mL H₂/day L_reactor were observed at the HRT of 0.25 h. The decrease in HRT from 8 to 0.25 h caused larger changes in the bacterial populations than the archaea populations. With the decrease in HRT (6 h–0.25 h), the Shannon diversity index decreased (3.02–2.87) for bacteria and increased (1.49–1.83) for archaea. The bacterial dominance increased (0.059–0.066) as the archaea dominance decreased (0.292–0.201) with the HRT decrease from 6 to 0.25 h.

中文翻译：

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通过更改HRT来控制EGSB反应器中干酪乳清中甲烷和氢气的产生

摘要

这项研究评估了中温（30°C）膨胀颗粒污泥床（EGSB）反应器中水力停留时间（HRT; 8 h–0.25 h）对奶酪乳清（5000 mg碳水化合物/ L）同时生产氢气和甲烷的影响。在HRT停留4到0.25 h时观察到甲烷的产生。最大的甲烷产量（9.8±1.9 mL CH ₄ / g COD _ap，报告为每克COD毫升CH ₄）和甲烷生产率（461±75 mL CH ₄ / day L_反应器）发生在4 h HRT和2小时。随着HRT从8小时降低到0.25小时，随着甲烷产量的减少，氢气产量增加。最大氢气产量为3.2±0.3 mL H ₂ / g COD _ap（报道为毫升水₂每克COD的施加）和1951±171毫升H的产氢速率₂ /日有效期的信用证_反应器分别以0.25小时的停留时间观察到的。HRT从8小时降低到0.25小时导致细菌种群的变化大于古细菌种群。随着HRT的降低（6 h-0.25 h），细菌的香农多样性指数降低（3.02-2.87），古细菌的香农多样性指数提高（1.49-1.83）。随着HRT从6 h降低到0.25 h，古细菌的优势减少（0.292–0.201），细菌的优势增加（0.059–0.066）。