• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.110-119
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• 2016

High-solid anaerobic digestion of sewage sludge achieves highly efficient volatile solid reduction, and production of volatile fatty acid (VFA) and methane compared with conventional low-solid anaerobic digestion. In this study, the potential mechanisms of the better performance in high-solid anaerobic digestion of sewage sludge were investigated by using 454 high-throughput pyrosequencing and real-time PCR to analyze the microbial characteristics in sewage sludge fermentation reactors. The results obtained by 454 highthroughput pyrosequencing revealed that the phyla Chloroflexi, Bacteroidetes, and Firmicutes were the dominant functional microorganisms in high-solid and low-solid anaerobic systems. Meanwhile, the real-time PCR assays showed that high-solid anaerobic digestion significantly increased the number of total bacteria, which enhanced the hydrolysis and acidification of sewage sludge. Further study indicated that the number of total archaea (dominated by Methanosarcina) in a high-solid anaerobic fermentation reactor was also higher than that in a low-solid reactor, resulting in higher VFA consumption and methane production. Hence, the increased key bacteria and methanogenic archaea involved in sewage sludge hydrolysis, acidification, and methanogenesis resulted in the better performance of high-solid anaerobic sewage sludge fermentation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.124-127
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• 2003

Sewage sludge and clay used as raw materials in the study. Green aggregates contain different contents by dried weight of the sewage sludge, up to 80 percent is manufactured and burning conditions of soak temperature, soak time and rate of temperature increase. influence of burning condition and mixing ratio on specific gravity of burned aggregate are discussed. The appropriate burning condition to all aggregates is evaluated. Aggregates result form the thermal treatment get specific gravity under 0.8, water absorption fewer than 7.5 percent, and aggregate crushing value from 28 to 53. As the result, aggregates can be available as the lightweight aggregate for non-structural concrete.

• 유기물자원화
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• 제12권4호
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• pp.105-111
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• 2004

환대 발생 직후의 줄지렁이에 제지슬러지, 농공지역(연천), 농업지역(남해)의 하수슬러지를 급이하였을 때, 104일 동안 줄지렁이가 생산한 난포수는 제지슬러지, 농업지역, 농공지역 순으로 각각 11.8, 8.6, 3.5개/마리였다. 그리고 제지슬러지를 급이한 경우는 조사기간동안 꾸준한 산란수를 유지하였으나 농공지역 하수슬러지를 급이한 지렁이는 먹이급이 52일 경과 후, 농업지역 하수슬러지는 먹이 급이 95일후부터 난포를 생산하지 못하였다. 환대 발생 직후의 줄지렁이에 농공지역(연천), 농업지역(남해)의 하수슬러지 및 제지슬러지를 급이하여 산란된 난포의 부화율은 각각 42.8, 38.3, 39.2%로 차이가 없었다. 그러나 연천하수슬러지와 남해하수슬러지를 급이한 경우 먹이 급이 46일, 43일 이후에 생산된 난포에서는 전혀 부화가 이루어지지 않았다. 부화기간은 33.8~36.0일로 먹이에 따른 차이는 없었다. 하수슬러지 및 제지슬러지를 급이한 후 생산된 난포에서 부화된 유충에 계속하여 하수슬러지 및 제지슬러지를 급이하였을 때, 먹이 급이 60일경과 후 지렁이의 치사율이 제지슬러지에서는 16%, 농업지역 하수슬러지에서는 90%, 농공지역 하수슬러지에서는 100%를 나타내었다.

• 도시과학
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• 제8권1호
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• pp.45-49
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• 2019

The land treatment of sewage sludge is necessary because sewage sludge is increasing year by year. Therefore the research of sewage sludge solidification is underway as one of the land treatment methods. However, the problem with existing sewage sludge solidification is that the moisture content of sewage sludge is high and the dewaterability is low. Because of high drying cost the efficiency of energy production is low and the calorific value is insufficient. So the disposer is supplied with a filtration and caloric aid for improving dewaterability and calorific value. In this study, it is aimed to improve the fuel value of sewage sludge by confirming the feasibility of waste wood as a filtration and caloric aid. The dewaterability was measured by CST-test and the calorific value was measured by bomb calorimeter. As a result the dewaterability and calorific value are improved in all of the samples. The dewaterability was improved as the waste wood was added in the sewage sludge. By adjusting the waste wood adding rate into the sewage sludge the dewaterability and calorific value of sewage sludge will be improved. This study confirmed possibility of the waste wood used as filtration and caloric aid.

• 자원환경지질
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• 제37권6호
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• pp.647-655
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• 2004

도시화가 진행되는 소유역(성내-고덕천 유역)에 대하여 지하수 질산성질소의 공간적 분포에 미치는 영향요인을 규명하고 각 요인들의 오염기여도에 대한 상대적인 차이를 파악하기 위하여 GIS를 활용한 공간분석을 실시하였다. 영향요인으로는 토지이용도, 하수관 거리, 포장율, 녹지율 등을 고려하였다. 공간분석 결과, 토지이용도 중에서 도시화 지역과 경작지 등에서는 서로 상이한 질산성질소 분포가 나타났으며, 이는 도시화 지역에서는 하수관으로, 경작지에서는 비료성분으로 인하여 질산성질소 분포의 차이가 나타날 수 있음을 지시한다. 지하수 관정에서 하수관까지의 거리가 $60\~75m$ 정도 지점까지는 거리의 증가에 따라 질산성질소 농도가 감소한다. 특히 도시화 지역 내에서 하수관거리와 질산성질소 농도가 음의 상관도를 보이며, 이는 하수관이 질산성질소의 주 오염원임을 의미한다. 또한, 도시화 지역 질산성질소 농도와 포장율이 음의 상관도를 보이는 것도 질산성질소의 오염물질이 지표면에 기인하고 있음을 지시한다. 결과적으로 도시화가 급속히 진행되고 있는 지역에서는 하수관의 설치와 유지관리 및 토지이용형태에 대한 체계적인 관리가 지하수의 질산성질소 오염예방에 중요함을 의미한다.

• 환경위생공학
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• 제21권3호
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• pp.27-36
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• 2006

For the last 20 years, China has transformed itself from a rural economy into an industrial giant, averaging over 8 % annual growth of GDP. Unfortunately, this rapid growth has taken a significant toll on its natural resource base as well, particularly water resources. These problems have been exacerbated by a low level of sewage treatment technology and by the operating and maintenance (O&M). In case of urban areas, most big cities in China have a well functioning sewage system comprised of sewers and sewage treatment plants (STPs). Nevertheless, the existing STPs are still not capable of properly treating the sewage, both quantitatively and qualitatively. The rural areas in China cover a large land, with two-third of the nation's population. The low educational and poor economic states make it hard to process self-protection and management. In the surveyed area in Henan, there was no STPs put into use as of 2004, and the sewer lines are not well organized. The big issue for the currently planned STPs is the collection system not included in the plans.

• 한국물환경학회지
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• 제23권4호
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• pp.482-489
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• 2007

Fluorescence properties and carbohydrate content were investigated using ultrafiltrated size fractions of dissolved organic matters (DOM) originated from different sources. The materials included a treated sewage, an algal organic matter, and a soil leachate, all of which are major constituents of dissolved organic matter in a typical urban river. Four different size fractions were separated from the three sources of each DOM. The size distribution demonstrated that a higher molecular weight fraction was more present in soil leachate compared to two other source DOMs. A higher content of carbohydrates was observed in the following order - algal DOM > treated sewage > soil leachate. A wide range of specific UV absorbance was observed from size fractions of a single source DOM, indicating that aromatic carbon structures are heterogeneously distributed within one source of DOM. The structural heterogeneity was the most pronounced for the soil leachate. The fluorescence index ($F_{450}/F_{500}$) of the treated sewage was similar to that (2.0) typically obtained from autochthonous DOM, suggesting that the treated sewage exhibited autochthonous organic matter-like properties. No protein-like fluorescence intensities were observed for all of the soil leachate size fractions whereas they were observed with two other source DOMs. Based upon the fluorescence peak ratios from fluorescence excitation-emission matrix (EEM), two discrimination indices could be suggested to distinguish three different source DOMs. It is expected that the suggested discrimination indices will be useful to predict the sources of DOM in a typical urban river affected by treated sewage.

• 한국환경과학회지
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• 제12권6호
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• pp.583-591
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• 2003

The research on potential energy was conducted to conserve the high-exergy energy like primary energy and utilize waste heat from sewage. From the Point of view in using the waste heat, the energy Potential of waste water from the model house was simulated. From the results, when the heated water was supplied to the model house side in order to put unused energy to Practice use, heated water had higher energy Potential than unheated water, which was due to the discharge of most of unused energy. The possessing heat capacity of sewage from heated water was increased to 40-70 percents in comparison with that from the unheated water. Therefore, it can be used as energy source for improving coefficient of performance of heat pumps. By adopting the multiple heat pump into a model house, It showed that the possessing heat capacity of sewage was reduced. It was also found that the heat was recovered as energy source fur multiple heat pump in a model house.

• 상하수도학회지
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• 제29권4호
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• pp.447-457
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• 2015

Water cycle within the human civilization has become important with urbanization. To date, water cycle in the eco-system has been the focus in identifying the degree of water cycle in cities, but in practicality, water cycle within the human civilization system is taking on an increasing importance. While in recent years plans to reuse water have been implemented to restore water cycle in cities, the effect that such reuse has on the entire water cycle system has not been analyzed. The analysis on the effect that water reuse has on urban areas needs to be go beyond measuring the cost-savings and look at the changes brought about in the entire city's water cycle system. This study uses a SWAT model and water balance analysis to review the effects that water reuse has on changes occurring in the urban water cycle system by linking the water cycle within the eco-system with that within the human civilization system. The SWAT model to calculate the components of water cycle in the human civilization system showed that similar to measured data, the daily changes and accumulative data can be simulated. When the amount of water reuse increases in urban areas, the surface outflow, amount of sewer discharge and the discharged amount from sewage treatment plants decrease, leading to a change in water cycle within our human civilization system. The determinant coefficients for reduced surface outflow amount and reduced sewer discharge were 0.9164 and 0.9892, respectively, while the determinant coefficient for reduced discharge of sewage treatment plants was 0.9988. This indicates that with an increase in water reuse, surface flow, sewage and discharge from sewage treatment plants all saw a linear reduction.

• 건축역사연구
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• 제28권6호
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• pp.55-65
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• 2019

Ganggyeong, a city which is located at riverside of Geum River, played a role to connect the inland cities and the coastal cities through the Geum river waterway. In Chosun dynasty, Ganggyeong was one of the three major markets in Korea, and at the same time, it was one of the two river docks in Korea. However, after the railway was installed in Korea, railroad was more important than waterway in transporting logistics and in 1911 Honam railroad and Ganggyeong railway station was installed. Thus it was necessary to reorganize urban structure of Ganggyeong city from the traditional river-dock city to modern railroad city. In addition, urban infrastructure to prevent flood damage was needed because Ganggyeong suffered from floods and water shortages every year. Therefore, between 1910s and 1930s large-scale social infrastructures including road, water and sewage system, river bank, floodgate was constructed not only to revitalize the declining city but also to prevent flood damage and water shortages that hinder urban development. The installation of urban infrastructure has enabled the urban expansion and development of Ganggyeong city, and it is still served as a basic urban structure.