• Journal of Microbiology and Biotechnology
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• v.23 no.3
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• pp.382-389
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• 2013

Propionate is an important intermediate product during the methane fermentation of organic matter, and its degradation is crucial for maintaining the performance of an anaerobic digester. In order to understand the effect of temperature on propionate degradation, an upflow anaerobic sludge blanket (UASB) reactor with synthetic wastewater containing propionate as a sole carbon source was introduced. Under the hydraulic retention time (HRT) of 10 h and influent propionate of 2,000 mg/l condition, propionate removal was above 94% at 30-$35^{\circ}C$, whereas propionate conversion was inhibited when temperature was suddenly decreased stepwise from $30^{\circ}C$ to $25^{\circ}C$, to $20^{\circ}C$, and then to $18^{\circ}C$. After a long-term operation, the propionate removal at $25^{\circ}C$ resumed to the value at 30- $35^{\circ}C$, whereas that at $20^{\circ}C$ and $18^{\circ}C$ was still lower than the value at $35^{\circ}C$ by 8.1% and 20.7%, respectively. Microbial community composition analysis showed that Syntrophobacter and Pelotomaculum were the major propionate-oxidizing bacteria (POB), and most POB had not changed with temperature decrease in the UASB. However, two POB were enriched at $18^{\circ}C$, indicating they were low temperature tolerant. Methanosaeta and Methanospirillum were the dominant methanogens in this UASB and remained constant during temperature decrease. Although the POB and methanogenic composition hardly changed with temperature decrease, the specific $COD_{Pro}$ removal rate of anaerobic sludge (SCRR) was reduced by 21.4%-46.4% compared with the control ($35^{\circ}C$) in this system.

• Resources Recycling
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• v.26 no.1
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• pp.59-68
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• 2017

This study has been conducted to evaluate the effects of a single stage anaerobic co-biogasification of food waste and primary sewage sludge mixture (1 : 5 V/V%) according to mixing ratio (0% : CAP0, 0.5% : CAP0.5, 1%: CAP1.0) in red pepper powder, which was reported as the material anti-bacterial and anti-fungi, under mesophilic condition ($35^{\circ}C$). during 31 days. It showed that red pepper powder effected anaerobic bacteria, Especially, Hydrolytic bacteria and methanogenic bacteria was inhibited much more than Acetogenic bacteria with red pepper powder. at CAP0, Experimental cumulative methane yield (ECMY) and Experimental bio-energy production (EBEP) were 0.17 L $CH_4/g$ $VS_{fed}$ and 1,465 cal/g $VS_{fed}$ individually as the highest value during 31 days.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.82-90
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• 2009

Disintegration of sewage sludge (SS) was investigated by batch experiments using mechanical pre-treatment. Mechanical disintegration of SS increased the amount of soluble chemical oxygen demand (SCOD), protein and carbohydrate due to the break-up of cell walls. The mechanical disintegration incorporated with alkaline pre-treatment demonstrated higher amount of SCOD compared with mechanical one only. In terms of anaerobic biodegradability, mechanical pretreatment enhanced the anaerobic biodegradation of SS, leading to the methane production improvement. The improvement in BMP for SS treated with mechanical and alkaline-mechanical pre-treatments were 24.1% and 44.5%, respectively. This result suggested that disintegration of SS was effective for improving anaerobic biodegradability.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.53-61
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• 2016

The reaction of zero-valent iron (ZVI) with oxygen can produce reactive oxidants capable of oxidizing organic compounds. Thus, the aim of this study was to investigate the effect of pre-treatment on sludge solubilization by ZVI and aeration. The results demonstrated that the aeration pre-treatment with ZVI method was more effective than the only aeration for improving sludge solubilization, indicating that ZVI increased the extent of sludge solubilization. In addition, removal rate of $NH_3-N$ by ZVI and aeration was found to be 34%, while only aeration was 24%. Thus, ZVI and aeration can be employed as an efficient pre-treatment option to achieve higher sludge solubilization and decrease the toxic effect of $NH_3-N$ for sludge digestion.

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.158.2-158
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• 1995

• 수도
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• s.42
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• pp.2-10
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• 1988

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1513-1518
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• 2017

Anaerobic mono- and co-digestion of sewage sludge and food waste leachate (FWL) were performed by assessing methane production and characterizing microbial communities. Anaerobic digestion (AD) of waste activated sludge (WAS) alone produced the lowest methane ($281ml\;CH_4$), but an approximately 80% increase in methane production was achieved via co-digestion of WAS and FWL ($506ml\;CH_4$). There were less differences in the diversity of bacterial communities in anaerobic digesters, while archaeal (ARC) and bacterial (BAC) amounts reflected AD performance. Compared with the total ARC and BAC amounts in the mono-digestion of WAS, the ARC and BAC amounts increased two and three times, respectively, during co-digestion of FWL and WAS. In characterized archaeal communities, the dominant ratio of hydrogenotrophic methanogens in the mono-digestion of WAS approached nearly a 1:1 ratio of the two acetoclastic and hydrogenotrophic methanogens in the co-digestion of FWL and WAS. The ARC/BAC ratio in the digesters varied in the range of 5.9% to 9.1%, indicating a positive correlation with the methane production of AD.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.362-372
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• 2010

Although different disposal routes of waste-activated sludge are possible, anaerobic digestion plays an important role for its abilities to further transform organic matter into methane. The potential of using methane as energy source has long been widely recognised and the present paper extensively reviews the principles of anaerobic digestion, the process parameters and hydrolysis. Hydrolysis is recognised as rate-limiting step in the complex digestion process. To accelerate the digestion and enhance the production of biogas, various pre-treatments can be used to improve the rate-limiting hydrolysis. These treatments include mechanical, thermal, chemical and biological interventions to the feedstock. All pre-treatments result in a lysis or disintegration of sludge cells, thus releasing and solubilizing intracellular material into the water phase and transforming refractory organic material into biodegradable species. The reader will finally be guided to extensive discussion for anaerobic digestion processes.

• Journal of Microbiology and Biotechnology
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• v.29 no.4
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• pp.633-644
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• 2019

An advanced anaerobic expanded granular sludge bed (AnaEG) and an internal circulation (IC) reactor, which were adopted to treat starch processing wastewater (SPW) and ethanol processing wastewater (EPW), were comprehensively analyzed to determine the key factors that affected the granules and microbial communities in the bioreactors. The granule size of $900{\mu}m$ in the AnaEG reactor was smaller than that in the IC reactor, and the internal and external morphological structures of the granular sludge were also significantly different between the two types of reactors. The biodiversity, which was higher in the AnaEG reactor, was mainly affected by reactor type. However, the specific microbial community structure was determined by the type of wastewater. Furthermore, the dominant methanogens of EPW were mainly Methanosaeta and Methanobacterium, but only Methanosaeta was a major constituent in SPW. Compared with the IC reactor, characteristics common to the AnaEG reactor were smaller granules, higher biodiversity and larger proportion of unknown species. The comparison of characteristics between these two reactors not only aids in understanding the novel AnaEG reactor type, but also elucidates the effects of reactor type and wastewater type on the microbial community and sludge structure. This information would be helpful in the application of the novel AnaEG reactor.

• KSBB Journal
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• v.25 no.1
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• pp.67-72
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• 2010

In this study, we developed a comprehensive correlation for better prediction of the activated sludge concentration in the relationship between measurement of optical density by the Beer's law and sludge properties. Effects of activated sludge properties, which are sludge types and anaerobic storage time, show that absorbance deviation for sludge properties decreased on wavelength of light source near to 950 nm. We also developed a method to measure limitation with non-linear correlation on the measurement of high concentration by the Beer's law using a double layer probe cell and empirical equations.