Biological hydrogen production in a UASB reactor with granules. II: Reactor performance in 3-year operation

✍ Scribed by Han-Qing Yu; Yang Mu

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 147 KB
• Volume: 94
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/bit.20923

✦ Synopsis

The experiment was conducted to evaluate the performance of an upflow anaerobic sludge blanket (UASB) with granules for H 2 production from a sucroserich synthetic wastewater at various substrate concentrations (5.33-28.07 g-COD/L) and hydraulic retention times (HRTs) (3-30 h) for over 3 years. The kinetics of H 2 production was evaluated, and the sludge yield and endogenous decay coefficient of the H 2 -producing granules were estimated to be 0.334 g-VSS/g-COD and 0.004/h, respectively. Based on Gibbs free energy calculations, the formation thermodynamics of caproate, an important aqueous product, were analyzed. Experimental results show that the H 2 partial pressure in biogas decreased with increasing substrate concentration, but was not sensitive to the variation of HRT in a range of 6-22 h. The H 2 production rate increased with increasing substrate concentration, but decreased with increasing HRT. The H 2 yield was in the range of 0.49-1.44 mol-H 2 /molglucose. Acetate, butyrate, caporate, and ethanol were the main aqueous products in the reactor, and their concentrations were dependent on both substrate concentration and HRT. An elevated substrate concentration resulted in a shift of fermentation from butyrate-to caporate-type in the reactor and the formation of caproate was dependent on the H 2 partial pressure. The 3-year experimental results demonstrate that H 2 could be produced continuously and stably from the acidogenicgranule-based UASB reactor.