Microbiome of Seven Full-Scale Anaerobic Digestion Plants in South Korea: Effect of Feedstock and Operational Parameters

Michal Sposob,Hee-Sung Moon,Dongjin Lee,Yeo-Myeong Yun

doi:10.3390/en14030665

Abstract

In this study, the microbiomes linked with the operational parameters in seven mesophilic full-scale AD plants mainly treating food waste (four plants) and sewage sludge (three plants) were analyzed. The results obtained indicated lower diversity and evenness of the microbial population in sludge digestion (SD) plants compared to food digestion (FD) plants. Candidatus Accumulibacter dominated (up to 42.1%) in SD plants due to microbial immigration from fed secondary sludge (up to 89%). Its potential activity in SD plants was correlated to H2 production, which was related to the dominance of hydrogenotrophic methanogens (Methanococcus). In FD plants, a balance between the hydrogenotrophic and methylotrophic pathways was found, while Flavobacterium and Levilinea played an important role during acidogenesis. Levilinea also expressed sensitivity to ammonia in FD plants. The substantial differences in hydraulic retention time (HRT), organic loading rate (OLR), and total ammonium nitrogen (TAN) among the studied FD plants did not influence the archaeal methane production pathway. In addition, the bacterial genera responsible for acetate production through syntrophy and homoacetogenesis (Smithella, Treponema) were present in all the plants studied.

Highlights

The growing world population as well as rapid economic development are leading to increased generation of organic wastes
The food chain of anaerobic digestion (AD) consists of four distinct stages involving the mutualistic behavior of various anaerobic microorganisms: bacteria are involved in hydrolysis, acidogenesis, and acetogenesis, while methanogenesis is performed by a specific branch of archaea via the hydrogenotrophic or acetoclastic pathway [5]
Higher concentrations of total ammonium nitrogen (TAN) were characteristic of food digestion (FD) plants compared to sludge digestion (SD) plants

Summary

Introduction

The growing world population as well as rapid economic development are leading to increased generation of organic wastes. Food waste (FW) and sewage sludge (SS) are the most copious and problematic forms of organic waste. Life-cycle assessment studies have shown that anaerobic digestion (AD) is a reliable option for the treatment of FW and SS and for biogas production [1,2,3]. The food chain of AD consists of four distinct stages involving the mutualistic behavior of various anaerobic microorganisms: bacteria are involved in hydrolysis, acidogenesis, and acetogenesis, while methanogenesis is performed by a specific branch of archaea via the hydrogenotrophic or acetoclastic pathway [5]. It is commonly accepted that the microbial community is a key factor for efficient biogas production [6]

Methods

Results

Conclusion