Microbial Substrate Storage And Hydrogen Utilization In Anaerobic Sequencing Batch And Continuous Flow Reactor

Microbial substrate storage and hydrogen utilization in glucose-fed anaerobic sequencing batch reactor (ASBR) and anaerobic continuous flow reactor were investigated.The results showed that microbial storage existed in anaerobic sequencing batch reactor. The fermentation bacteria (Glycogen Accumulating Organisms, GAOs) accumulated the substrate transiently and stored in the cell as the form of glycogen during feast period; glycogen stored in the cell was utilized in the following famine period. Glycogen storage can not only slow down the accumulation of VFA, but reduce the production rate of hydrogen, lower hydrogen partial pressure in ASBR, create a good condition for the stable and efficient operation of ASBR. Under the same conditions, there hardly existed glycogen storage, and hydrogen partial pressure is relatively high in anaerobic continuous flow reactor.The maximum utilization rate of hydrogen was 24.65 ml-H2/gVSS·h in ASBR, and 60.81 ml-H2/gVSS·h in continuous flow reactor. The date illustrated that activated sludge in continuous flow reactor had higher potential of utilizing hydrogen than activated sludge in ASBR. The maximum specific methanogenic activity in ASBR for acetate, propionate, butyrate and ethanol were 0.396 gCOD-CH₄/gVSS·d, 0.464 gCOD-CH₄/gVSS·d, 0.096 gCOD-CH₄/gVSS·d and 0.492 gCOD-CH₄/gVSS·d; and 1.073 gCOD-CH₄/gVSS·d, 0.602 gCOD-CH₄/gVSS·d, 0.880 gCOD-CH₄/gVSS·d and 1.348 gCOD-CH₄/gVSS·d in continuous flow reactor.Sludge morphology was obviously different in two reactors. Activated sludge in ASBR was larger flocs, and had clear boundary. There was no filamentous bacteria. SVI was about 43 ml/g, the settling performance of sludge was good, and less activated sludge effused from reactor. On the contrary, activated sludge in anaerobic continuous flow reactor has a large number of filamentous bacteria, and SVI was about 140 ml/g, sludge settling performance was poor, much activated sludge effused from reactor.