• 신재생에너지
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• 제10권1호
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• pp.20-29
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• 2014

The present study investigated the effects of thermal pre-treatment on the enhancement of anaerobic biodegradability of waste activated sludge at varied TS concentration levels. The activated sludges were thermally oxidized for 30 minutes at $80{\sim}200^{\circ}C$ with varied TS concentrations (2%, 4% and 6%). and then, sludge characteristics, solubilization efficiency and methane production yield of thermally pre-treated sludges were analyzed. The higher the temperature in the thermal pre-treatment, the higher the concentration levels of dissolved matters such as $SCOD_{Cr}$, $NH_4{^+}$ and VFAs, which indicates that the thermal pre-treatment facilitates the hydrolysis and acid fermentation. Furthermore, the solubilization efficiency was increased in proportion to the temperature rise at all TS concentrations and was reached at 68.9%, 55.6% and 53.1%, respectively, at $200^{\circ}C$. In the BMP test of the pre-treated sludges, higher methane production yields were observed as 0.313. 0.314 and $0.299m^3\;CH_4/kg\;VS_{add}$ at the condition of TS 2% ($160^{\circ}C$), 4% ($160^{\circ}C$) and 6% ($180^{\circ}C$), respectively, and degradation rate was increased by 84%, 79% and 65% compared with non-pretreated waste activated sludge. These findings suggest the effectiveness of thermal pre-treatment of waste activated sludge for anaerobic biodegradable process.

• Journal of Microbiology and Biotechnology
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• 제22권7호
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• pp.1005-1014
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• 2012

The understanding of the relationship between ammonia-oxidizing bacteria (AOB) communities in activated sludge and the operational treatment parameters supports the control of the treatment of ammonia-rich wastewater. The modifications of treatment parameters by alteration of the number and length of aerobic and anaerobic stages in the sequencing batch reactor (SBR) working cycle may influence the efficiency of ammonium oxidation and induce changes in the AOB community. Therefore, in the research, the impact of an SBR cycle mode with alternating aeration/mixing conditions (7 h/1 h vs. 4 h/5.5 h) and volumetric exchange rate (n) on AOB abundance and diversity in activated sludge during the treatment of anaerobic sludge digester supernatant at limited oxygen concentration in the aeration stage (0.7 mg $O_2/l$) was assessed. AOB diversity expressed by the Shannon-Wiener index (H') was determined by the cycle mode. At aeration/mixing stage lengths of 7 h/1 h, H' averaged $2.48{\pm}0.17$, while at 4 h/5.5 h it was $2.35{\pm}0.16$. At the given mode, AOB diversity decreased with increasing n. The cycle mode did not affect AOB abundance; however, a higher AOB abundance in activated sludge was promoted by decreasing the volumetric exchange rate. The sequences clustering with Nitrosospira sp. NpAV revealed the uniqueness of the AOB community and the simultaneously lower ability of adaptation of Nitrosospira sp. to the operational parameters applied in comparison with Nitrosomonas sp.

• 한국축산시설환경학회지
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• 제5권3호
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• pp.189-196
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• 1999

Anaerobic digestion is a naturally occuring microbial process involving the decomposition of organic materials such as livestock manure. This study explores the effect of the operating conditions, HRT (Hydraulic Retention Time) and feeding frequency on treatment efficiency for digestion of pig slurry, which has been one of most difficult organic waste for proper treatment in livestock production industry in Korea at the present time. The pilot-scale CSTR of 5 m3 in volume was designed. manufactured, and operated at the temperature of 35$\pm$1$^{\circ}C$. The digester was designed to hydraulically stir for complete mixing and to supply heat from the water bath to maintain mesophilic temperature. The HRT of the digester for Test 1 and Test 2, and Test 3 was set for 17 days and 13 days respectively and pig slurry was fed once a day with 300$\ell$ each for Test 1 and Test 3, while twice with 150$\ell$each for Test 2. Test 2 showed better performance by increase of 4% in VS removal efficiency and 5% in biogas production rate. This is mainly attributed to smaller temperature drop by feeding frequently with half amount, which eventually led to lesser impact on anaerobic mocrobes in the digester. Test 2 maintained optimum pH 7.8 which uplifted the activaton of sulfur-reduction bacteria, alkalinity of around 4,000mg/$\ell$, VA of over 3,000mg/$\ell$ for whole period of experiment. Further research may require to provide the practical operation strategy of anaerobic treatment system for treatment of pig slurry.

• 한국작물학회지
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• 제41권2호
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• pp.139-144
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• 1996

발아후 일주일간 생육한 보리 유식물체를 이용하여 혐기처리, 저온처리 및 기계적 상처에 대한 보리 식물체의 반응양상을 유리아미노산과 유리당 함량의 변화를 분석하여 조사하였다. 혐기적처리에 반응하여 함량의 변화가 뚜렸하게 나타나는 아미노산은 alanine, GABA, glutamic acid였다. Alanlne과 GABA함량은 10시간까지의 혐기처리에 의해 급속히 증가하였으나 glutamic acid 함량은 크게 감소하는 경향을 나타내었다. 상처에 의한 alanine, GABA, glutamic acid반응 양상은 혐기처리와 유사하였으나, 함량변화 정도는 혐기처리에서 보다 훨씬 낮았다. 저온처리에 의하여 지상부와 뿌리 중의 GABA 함량이 증가하였다. 혐기적 처리에 의하여 지상부의 유리당함량이 변화하였으며, glucose나 fructose보다는 sucrose의 함량변화가 상대적으로 크게 나타났다

• Environmental Engineering Research
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• 제11권3호
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• pp.134-142
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• 2006

The treatment of high-strength swine wastewater by anaerobic digestion combined with an aquatic plant system was investigated. Anaerobic digestion of swine wastewater gave volatile solids (VS) removal efficiencies of 43.3%, 52.1% and 54.5% for hydraulic retention times (HRTs) of 20, 30, 40 days, respectively. The removal efficiencies of VS, total chemical oxygen demand (TCOD) and soluble chemical oxygen demand (SCOD) decreased with increasing VS volumetric loading rate (VLR). Higher organic removal efficiency was observed at longer HRTs for the same VS volumetric loading rate. As VS volumetric loading rate increased, biogas production increased and the methane content of the biogas decreased. Experiments using duckweed (Lemna species) as an aquatic macrophyte gave the following results. In the case of nitrogen, removal efficiency was above 60% and effluent concentration was below 10.0 mg/L when the influent ammonia-N loading was about $1.0\;g/m^2/day$. In the case of phosphorus, removal efficiency was above 55% and effluent concentration was below 2.0 mg/L when the influent $PO_4$-P loading was about $0.15\;g/m^2/day$. In addition, crude protein and phosphorus content of duckweed biomass increased from 15.6% to 41.6% and from 0.8% to 1.6%, respectively, as the influent nutrient concentration increased. The treatment of high-strength swine wastewater by anaerobic digestion combined with an aquatic plant system offers good performance in terms of organics and nutrient removal for relatively low operation and maintenance costs. The results indicate that under appropriate operational conditions, the effluent quality is within the limits set by Korean discharge criteria.

• 유기물자원화
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• 제30권4호
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• pp.27-40
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• 2022

본 연구에서는, 탈수슬러지 및 음식물류폐기물의 효율적인 병합혐기성소화를 위해 폐기물의 혐기성소화 가능성 및 열화학적 전처리 방법에 대해 평가하였다. 폐기물의 혐기성소화 가능성 평가 결과, 음식물류폐기물이 탈수슬러지에 비해 혐기성미생물에 의해 분해 가능한 유기물 농도 및 methane yield가 각각 2.2배, 1.3배 더 높게 평가되었다. 바이오가스 발생량의 증대를 위해서는, 음식물류폐기물의 혼합비율을 증가시키는 것이 필요할 것으로 판단되었으며, 열화학적 전처리 효율은 반응온도, NaOH 주입량, 반응시간, 혼합비율 조건에 대해 평가하였다. 전처리 효율 및 탈수능을 통해 평가한 결과, 최적 열화학적 가용화 전처리 조건은 반응온도 140℃, NaOH 주입량 60 meq/L, 반응시간 60 min, 혼합비율 1:5로 평가되었다. 최적 열화학적 가용화 전처리 조건 적용 전과 후의 methane yield를 비교한 결과, 전처리를 적용한 경우에서, 가스발생속도 및 methane yield가 각각 1.6, 1.5배 증가하였다. 따라서, 탈수슬러지 및 음식물류폐기물의 효율적인 병합혐기성소화를 위해서는 음식물류폐기물의 혼합비율을 증가시키며, 폐기물의 전처리를 통해 가용화 효율을 증대시키는 것이 필요하다고 판단된다.

• 환경위생공학
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• 제10권3호
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• pp.1.1-15
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• 1995

This study was performed to estimate the characteristics of the organic wastewater treatment and bed porosity with the circulation velocity in the anaerobic fluidized bed biofilm reactor. The results were as follows; 1. With Increasing circulation velocity the fluidized bed expanded smooth and with increasing initial particle volume the fluidized bed was increased. 2. With increasing circulation velocity the gasproduction was increased, but at 1.Scnt/sec of circulation velocity AFBBR showed the highest value of methane production rate per removed COD. Therefore, for the purpose of economical operation in AFBBR, 1.5cm/sec of circulation velocity was optimum 3. The microorganisms were colonized in the crevice of the media. 4. On fluidization, COD, VA,55 profiles with the reactor height were not showed. In conclusion, AFBBR suit the organic wastewater treatment's purpose, and at 1.5cm/sec of circulation velocity the system is economical in an energy Point of view.

• 신재생에너지
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• 제1권2호
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• pp.60-72
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• 2005

The effect of alkaline pre-treatment on the solubilization of waste activated sludge(WAS) was investigated, and the biodegradability of WAS, pretreated WAS, [PWAS], food waste and two types of mixture were estimated by biochemical methane potential [BMP] test at $35^{\circ}C$. The biodegradability of PWAS and mixture waste were significantly improved due to the effect of alkaline hydrolysis of WAS. An alkaline pre-treatment was identified to be one of the useful pre-treatment for improving biodegradability of WAS and mixture waste. In high-rate anaerobic co-digestion system coordinate with an alkaline pre-treatment in process, the digesters were operated at the HRT of 5, 7, 10 and 13 days with a mixture of FW $50\%\;and\;PWAS\;50\%,\;$In term of $CH_4$ content, VS removal and specific methane production [SMP] which are the parameters in the performance of digester, the optimum operating condition was found to be a HRT of 7 days and a OLR of 4.20g/L-day with the highest SMP of 0.340 L $CH_4/g$ VS.

• Environmental Engineering Research
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• 제25권1호
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• pp.80-87
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• 2020

Landfill waste decomposition generates a dark effluent named, leachate which is characterized by high organic matter content. To minimize these polluting effects, it becomes necessary to develop an effective landfill leachate treatment process. The objective of this study was to evaluate the performance of an innovative approach based on air stripping, anaerobic digestion (AD) and aerobic activated sludge treatment. A reduction of 80% of ammonia and an increase of carbon to nitrogen ratio to 25 were obtained, which is a suitable ratio for AD. This latter AD was performed in fixed bed reactor with progressive loading rate that reached 2 and 3.2 g COD/L/d for the raw and diluted leachate (1:2), respectively. The anaerobic treatment led to significant removal of chemical oxygen demand (COD) and biogas production, especially for the diluted leachate. The COD removal was of 78% for the raw leachate and a biogas production of 4 L/d with 70% methane content. The use of the diluted leachate led to 81% of COD removal and 7 L/d biogas with 75% methane content. It allowed a removal of 77% COD and more than 97% of the organic compounds present in the initial leachate sample.

• 한국수소및신에너지학회논문집
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• 제15권3호
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• pp.187-193
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• 2004

In this study, Anaerobic sewage sludge in a batch reactor operation at $35^\circ{C}$ was used as the seed to investigate the effect of pretreatments of waste activated sludge and to evaluate its hydrogen production potential by anaerobic fermentation. Various pretreatments including physical, chemical and biological means were conducted to utilize for substrate. As a result, SCODcr of alkali and mechanical treatment was 15 and 12 times enhanced, compared with a supernatant of activated sludge. And SCODcr was 2 time increase after re-treatment with biological hydrolysis. Those were shown that sequential hybridized treatment of sludge by chemical & biological methods to conform hydrogen production potential in bath experiments. When buffer solution was added to the activated sludge, hydrogen production potential increased as compare with no addition. Combination of alkali and mechanical treatment was higher in hydrogen production potential than other treatments.