Performance and characterization of a newly developed self-agitated anaerobic reactor with biological desulfurization

Effect of Mixing Driven by Siphon Flow: Parallel Experiments Using the Anaerobic Reactors with Different Mixing Modes

“…The depth of the scum plus the sludge during Phase 4 was typically 45 cm, whereas it was about 35-37 cm during Phases 1 and 2, implying the scum layer on the sludge surface was approximately 10 cm thick during Phase 4. This result was quite different from that obtained in our previous study [13], which involved the use of an artificial food waste feedstock. In this previous study, no scum formation was observed in the SMR during the OLR of 5-10 kg-COD/m 3 /day.…”

“…During Phases 1 and 2, all the three reactors maintained active gas production, with the gas production rates increasing with shorter HRTs. The frequency of siphon mixing depends on biogas production rate in the C1 [13]. In this case, mixing occurred approximately five times (Phase 1) and 10 times (Phase 2) per day in the SMR.…”

“…A simple powerless mixing system using a siphon flow, which enables the successful operation of anaerobic digestion [13], is thought to have much potential for use in small-scale digesters. A fluid dynamics analysis has shown a significant improvement in sludge mixing when the reactor is mixed by the siphon flow [14].…”

“…As such, this mixing system is expected to enhance digestion performance and avoid stratification, without creating excessive costs. However, the previous studies [13,14] did not adequately assess the advantages of the siphon mixed reactor (SMR) over the standard unmixed reactor. In addition, there is a need to examine a difference between the SMR and the continuously mixed reactor (CMR), in order to determine whether siphon mixing is actually capable of serving as a substitute for the commonly used digesters with continuous mechanical mixing.…”

Hydrodynamic behaviour and its effects on the treatment performance of panelled anaerobic baffle-cum filter reactor

“…The diffusion in the fourth chamber is much weaker, and the flow characteristic tends to PF, due to the decrease in organic loading and gas production. Kobayashi and Li (2011) studied the self-agitated anaerobic reactor and found that alkalinity and pH value were distributed equally in the first three compartments due to CSTR flow condition; slight rise in the pH and alkalinity was noticed in the fourth chamber which behaves like PF type. Ji et al (2014) investigated the hydrodynamic behaviour of staged up-flow anaerobic ammonium oxidation (ANAMMOX) sludge bed (SUASB) reactor and found that the reactor behaviour was in between PF and CSTR.…”