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Domestic organic waste resources have increased over the past decade and treatment of this waste via co-digested biogasification facilities is increasing annually. However, inspection standards for such facilities are not well-established. Herein, we aimed to derive calculation formulas and factors related to organic matter decomposition efficiency and methane production rate in accordance with waste treatment facility inspection standards. We also aimed to determine the optimum waste mixing ratio. Sample (field) surveys of 18 treatment facilities and complete enumeration of 110 facilities were conducted. Calculation formulas and factors were derived using the survey data and biochemical methane potential (BMP) test. The calculated coefficients derived through the BMP test were 0.512 m3 CH 4 /kgVS in for food waste, 0.601 m3 CH 4 /kgVS in for livestock manure, and 0.382 m3 CH 4 /kgVS in for sewage sludge. The final derived calculation factors were 65.0% for food waste, 36.0% for livestock manure, and 20.0% for sewage sludge for organic matter decomposition efficiency, and 0.380 m3 CH 4 /kgVS in for food waste, 0.27 m3 CH 4 /kgVS in for livestock manure, and 0.140 m3 CH 4 /kgVS in for sewage sludge for methane production rates. The derived effective capacity calculation factors can be utilized in future waste treatment facility inspection methods by aiding in the establishment of appropriate inspection standards for co-digested biogasification facilities other than single food waste treatment facilities. In addition, the optimum mixing ratio can be used as design data for co-digested biogasification facilities. • An inspection standard for organic waste co-digestion facilities was determined • Highest methane production food waste: livestock manure: sewage sludge ratio is 0.402:0.592:0.006 • Decomposition and methane production rates used to assess suitability of facility [ABSTRACT FROM AUTHOR]

The operational temperature and nature of the substrates are two critical parameters in shaping the functional microbiota and determining the biogas productivity of field-scale anaerobic digesters. Elucidating microbial ecological configurations and dynamics as a function of parametric (temperature, pH, substrate variability etc.) variations is pivotal for effective process management, improving the process stability and digestion efficiency of large field-scale anaerobic digesters. Seventeen field-scale digesters treating food waste leachate, municipal wastewater sludge (MWS), and manure at 10 different sites across the Republic of Korea were studied to assess how substrate variations, including co-digestion and seasonal variation, affect biogas productivity and the compositional dynamics of the digester microbiota. The 16S rRNA gene metataxonomics and predictive metabolic pathway profiling revealed significant differences in the phylogenetic composition of the microbiota between the digester types depending on the presence of MWS in the substrate (p < 0.005). A clear compositional divergence was observed between the MWS and non-MWS substrate groups, with a high prevalence of Firmicutes and versatile organic matter-degrading genera (Fastidiosipila , Acholeplasma , etc.) in the non-MWS digesters, resulting in a significantly high biogas yield (53.4 Nm3/t). Predictive metabolic pathway profiling demonstrated the importance of acetoclastic methanogenesis in all anaerobic digestion groups subjected to the study. The results of this study suggest that metataxonomics and microbiota dynamics are good indicators of the process stability and efficiency of field-scale digesters across the parametric variations of field anaerobic digester systems. • Microbiota dynamics in large field-scale AD of various substrates were assessed. • A significant microbiota variance was observed between MWS and FWL-fed digesters. • Microbial dynamics of FWL digester group reflect significantly high biogas yield. • FWL digesters had high METH-ACETATE-PWY (acetoclastic methanogenesis) activity. [ABSTRACT FROM AUTHOR]

Due to the ban on the use of food waste as wet swine feed after the outbreak of African swine fever (ASF), 2900 tons/day of food waste and 1083 tons/day of food waste leachate were additionally generated. As an alternative treatment method for food waste leachate, the input of food waste leachate on weekends (5% of food waste leachate inflow, 100 tons/day) and its increased input (merge ratio 21.7%, 227.01 tons/day → 27.8%, 453.71 tons/day) into the digesters operated in a public sewage treatment plant were investigated. Additionally, the feasibility of the method was evaluated by analyzing the operation parameters, evaluating the operation efficiency, and identifying other environmental effects on the sewage treatment plant. In the case of input on weekends, the organic matter decomposition rate and gas production rate decreased by 8.0% and 9.5%, respectively, although the input on weekends was judged to be feasible, considering that the inflow into the WWTP increased by up to 206% due to the long-term (7 weeks) monsoon. In the case of the increased input of food waste leachate, the organic matter decomposition and gas production rates increased by 2.5% and 4.8%, respectively, compared with before the increased input. The results of this study confirmed that the additional input of food waste leachate into existing biogasification facilities is feasible. When performed in a stable manner, the use of food waste for anaerobic digestion is considered an appropriate alternative treatment method to wet feed. This will lead to technological and industrial development. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]