Anaerobic digestion of dried/shredded food waste in a periodic anaerobic baffled reactor

Abstract

The objective of the current work is to study the impact of the operational parameters' variation (HRT, OLR and T) on biomethane productivity in a Periodic Anaerobic Baffled Reactor (PABR). The feedstock used was a biomass product named FORBI (Food Residue Biomass), which is dried and shredded source-separated household food waste. The Periodic Anaerobic Baffled Reactor (PABR) is an innovative, high-rate bioreactor. Apart from the Hydraulic Retention Time (HRT) and the Organic Loading Rate (OLR), an important operational parameter is the Switching Period (T) of the feeding compartment: when T is high, the bioreactor operation is similar to an Anaerobic baffled reactor (ABR), while when it is low, the operation approaches that of an Upflow Anaerobic Sludge Blanket Reactor (UASBR). Nine distinct experimental phases were conducted, during which the operational parameters of the PABR were consecutively modified: the HRT varied from 9 to 2.5 days, T between 2 days and 1 and finally the OLR from 1.24 gCOD/Lbioreactor*d to 8.08 gCOD/Lbioreactor*d. The maximum biomethane yield was 384 LCH4/kgFORBI corresponding to the operation at HRT = 5 d, OLR = 2.14 gCOD/Lbioreactor*d and T = 2 days. Similar efficiency (333 LCH4/kg­FORBI) was achieved at higher OLR (4.53 gCOD/Lbioreactor*d).

Hydrodynamic behavior and start-up performance of a periodic anaerobic baffled reactor in an “every second” switching manner treating traditional Chinese medicine wastewater

“…In addition to the switching frequency, there are two switching manners viable for the PABR viewing from the top, namely, "clockwise sequential" (Figure 1C) and "every second" (Figure 1D). Most studies found in the literature focus on the "clockwise sequential" switching manner for synthetic (Skiadas and Lyberatos, 1998;Skiadas et al, 2000;Stamatelatou et al, 2003Stamatelatou et al, , 2004, real industrial (Liu et al, 2009;Stamatelatou et al, 2009), or municipal (Zarkaliou et al, 2022) wastewater and food residue biomass (Mathioudakis et al, 2021) treatments, although simulation taken from the study by Skiadas and Lyberatos (1998) predicted that the "every second" option seemed to lead to slightly higher performance and less fluctuation of the effluent concentration compared with the "clockwise sequential".…”