Changes of Bacterial Communities in an Anaerobic Digestion and a Bio-Electrochemical Anaerobic Digestion Reactors According to Organic Load

Abstract

Bacterial communities change in bulk solution of anaerobic digestion (AD) and bio-electrochemical anaerobic digestion reactors (BEAD) were monitored at each organic loading rate (OLR) to investigate the effect of voltage supply on bacterial species change in bulk solution. Chemical oxygen demand (COD) degradation and methane production from AD and BEAD reactors were also analyzed by gradually increasing food waste OLR. The BEAD reactor maintained stable COD removal and methane production at 6.0 kg/m3·d. The maximum OLR of AD reactor for optimal operation was 4.0 kg/m3·d. pH and alkalinity decline and volatile fatty acid (VFA) accumulation, which are the problem in high load anaerobic digestion of readily decomposable food wastes, were again the major factors destroying the optimal operation condition of the AD reactor at 6.0 kg/m3·d. Contrarily, the electrochemically activated dense communities of exoelectrogenic bacteria and VFA-oxidizing bacteria prevented VFAs from accumulating inside the BEAD reactor. This maintained stable pH and alkalinity conditions, ultimately contributing to stable methane production.

Improvement of Waste Dehydrated Sludge for Anaerobic Digestion through High-Temperature and High-Pressure Solubilization

“…In addition, the generated methane production was converted to the normal state through Equations (5) and (6).…”

“…At present, the methods to reduce waste hydrated sludge include aerobic and anaerobic decomposition directly in the treatment facility, as well as recycling practices such as the use of sludge as fertilizer or fuel [5]. Anaerobic digestion is advantageous over aerobic decomposition due to its relatively low energy consumption, effective elimination and reduction of harmful bacteria, and stable operation when treating waste hydrated sludge [6]. However, most anaerobic digesters in operation present low biological oxygen demand (BOD) concentrations in the influent sewage.…”

Evaluation of the Effect of the Application of Combined Pretreatments and Inoculum with High Alkalinity on Food Residues Through BMP Tests

“…EU 9 (inoculum blank) did not show any biogas production. According to Jiang et al [38] and Park et al [39], the amount of available feed is a key factor for the maintenance of optimal conditions for the anaerobic process and biogas production. This segmentation Fig.…”

The effect of reduced graphene oxide addition on methane production from municipal organic solid waste

“…3 The anaerobic digestion process involves a group of microbial reactions that produce renewable energy in the form of methane by treating mainly organic wastes and wastewater. 4 Anaerobic digestion consists of hydrolysis, acidogenic fermentation, hydrogen-producing acetogenesis and methanogenesis stages. The main species for the production of the final product, methane, are methanogens.…”