Biogas Production from Organic Wastes in Korea: Waste Characteristics and Applicability of Anaerobic Co-digestion

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Implications of introducing fluctuations in substrate concentration on the process performance of horizontal anaerobic reactors

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유입 기질 농도 변동에 따른 수평형 혐기성 반응기의 공정 효율 평가

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4차 산업시대의 유기성 폐자원 에너지화 기술

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Microbial communities underpinning mesophilic anaerobic digesters treating food wastewater or sewage sludge: A full-scale study

Ten mesophilic full-scale anaerobic digesters treating food wastewater (FW-digesters) or sewage sludge (SL-digesters) were monitored for 1 year to investigate: (1) microbial communities underpinning FW-digesters and SL-digesters, (2) the effects of total ammonia-nitrogen concentration [TAN] and Na+ concentration [Na+] on variations of these communities. [TAN] and [Na+] in the digester varied among digesters: 1.7-6.5 g TAN/L and 1.0-3.6 g Na+/L for the FW-digesters, and 0.1-2.2 g TAN/L and 0.1-1.2 g Na+/L for the SL-digesters; [TAN] negatively correlated with the process efficiency of the FW-digesters. Microbial communities were less diverse in the FW-digesters than in the SL-digesters. The FW- and SL-digesters formed very distinct microbial community structures; [TAN] and [Na+] in the digester were the critical factors shaping these structures. Immigrant bacteria from influent sludge significantly influence the bacterial communities of the SL-digesters. Methanoculleus might be tolerant to high ammonia in AD of such organic wastewater.11Nsciescopu

Use of food waste-recycling wastewater as an alternative carbon source for denitrification process: A full-scale study

Using organic wastes as an alternative to commercial carbon sources could be beneficial by reducing costs and environmental impacts. In this study, food waste-recycling wastewater (FRW) was evaluated as an alternative carbon source for biological denitrification over a period of seven months in a full-scale sewage wastewater treatment plant. The denitrification performance was stable with a mean nitrate removal efficiency of 97.2%. Propionate was initially the most persistent volatile fatty acid, but was completely utilized after 19 days. Eubacteriacea, Saprospiraceae, Rhodocyclaceae and Comamonadaceae were the major bacterial families during FRW treatment and were regarded as responsible for hydrolysis (former two) and nitrate removal (latter two) of FRW. These results demonstrate that FRW can be an effective external carbon source; process stabilization was linked to the acclimation and function of bacterial populations to the change of carbon source.113sciescopu

Chemical constituents of petersianthus quadrialatus (Merr.)

The dichloromethane extract of the twigs of Petersianthus quadrialatus (Merr.) afforded stigmasterol (1) and taraxerol (2), while the leaves yielded 1, unsaturated triglycerides (3) and a mixture of β-amyrin fatty acid ester (4a) and α-amyrin fatty acid ester (4b) in a 2:1 ratio. The structures of 1-4b were identified by comparison of their 1H and/or 13C NMR data with those reported in the literature

Resorcinols from Myristica philippensis Lam

The dichloromethane extract of the leaves of Myristica philippensis Lam. afforded two resorcinols, malabaricone C (1) and malabaricone B (2), and β-sitosterol. The structure of 1 was elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by mass spectrometry. The structure of 2 was deduced by comparison of its 1H NMR data with those of 1and confirmed by comparison of its 13C NMR data with malabaricone B

Enhancement of Hydrolysis and Biogas Production of Primary Sludge by Use of Mixtures of Protease and Lipase

This study aims to improve the hydrolysis and degradation of primary sludge by using wild-type enzymes (protease and lipase) and establishing the optimal enzymatic cocktail ratio. Primary sludge from three wastewater treatment plants (WWTPs) in Korea (Ulsan, Pohang, and Busan) were subjected to enzymatic hydrolysis. Protease and lipase were isolated from enzyme-producing microorganisms cultured from secondary sludge collected at 8 different digester sites in Korea. Primary sludge degradation through enzymatic hydrolysis was monitored by measuring the reduction in the volatile suspended solids (VSS) content of the sludge and enzyme cocktail mix for 72 h at 40(o)C and pH 7.0. The enzymatic cocktail of Ulsan primary sludge treated with protease to lipase at a ratio of 1:3 was found to be optimal at 33.3% VSS reduction. Biochemical methane potential (BMP) tests were employed to the optimal enzyme cocktail to measure the potential of the hydrolyzed substrate for further degradation (VSS reduction) and bioconversion to biogas using 125 mL serum bottles as anaerobic reactors for 30 days. BMP tests showed that there was an increase in biogas production by 84.1%, methane production by 89.8%, and methane yield by 9.6%. Methane production rate was also increased. The significant VSS concentration reduction and higher biogas and methane yield of the enzyme-treated primary sludge correlate to the fact that the complex polymeric organic materials were degraded leading to efficient utilization by the microorganisms in the anaerobic digestion process.11Nsciescopuskc