• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.1
• /
• pp.15-25
• /
• 2006

This study was initiated to evaluate the effect of HRT(hydraulic retention time) on removal efficiencies of organic matter (C), nitrogen(N) and phosphorus(P) in municipal wastewater for suspenced-growth processes(MLE; Modified Ludzack-Ettinger) and hybrid process(Modified-Dephanox). M-Dephanox process was designed to improve the performance of Dephanox process on denitrification efficiency. As the results, removal efficiencies of C, N and P in M-Dephanox process, which is hybrid process, were higher than those in MLE, which is suspended-growth process. Especially, nitrification inhibition of MLE was observed more severely than M-Dephanox as hydraulic retention time was reduced from 6 hr to 3.5 hr. Nitrification in nitrification reactors on M-Dephanox, at short HRT, was so excellent that ammonia nitrogen removal efficiency in nitrification reactors of M-Dephanox was about 92% at 1.59 hr of HRT of nitrification reactors, however, nitrification in nitrification reactors on M-Dephanox was affected severely by organic matter entering to nitrification reactors from downstream settler. It was observed that reducing of HRT in whole process resulted from reducing of HRT in nitrification reactors on M-Dephanox.

• Proceedings of the Botanical Society of Korea Conference
• /
• 1989.08a
• /
• pp.113-118
• /
• 1989

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2000.11a
• /
• pp.211-214
• /
• 2000

휘발성 유기물질은 ground level ozone의 전구체로써 미래 대기오염의 주원인이 될것으로 판단되는 물질이며 구미각국에서는 1990년 초반부터 그리고 국내에서는 최근에 와서 규제가 확정된 물질이다. 대표적인 휘발성 유기물질의 종류와 배출원을 Table 1과 Table 2에 나타내었다.(중략)

• Environmental engineer
• /
• v.19 s.186
• /
• pp.66-73
• /
• 2002

우리나라 하수의 특성이 유기물 농도가 질소 농도에 비하여 매우 낮기 때문에 외국의 종속영양 탈질 공법을 그대로 적용하기가 힘들며 적용한다 할지라도 외부탄소원을 넣어야 하므로 경제적인 처리는 불가능하다. 산업폐수의 경우에 있어서도 유기물농도가 질소농도에 비하여 낮은 폐수의 경우는 값비싼 외부탄소원을 넣어주어야 한다. 따라서 폐수 특성에 맞는 효율적이고 경제적인 질소화합물 제거 기술의 개발은 불가피하다. 따라서 종속영양탈질공정의 경제성 문제 및 기존의 황탈

• Environmental engineer
• /
• s.183
• /
• pp.70-77
• /
• 2001

우리나라 하수의 특성이 유기물 농도가 질소농도에 비하여 매우 낮기 때문에 외국의 종속영양 탈질 공법을 그대로 적용하기가 힘들며 적용한다 할지라도 외부탄소원을 넣어야 하므로 경제적인 처리는 불가능하다. 산업폐수의 경우에 있어서도 유기물농도가 질소농도에 비하여 낮은 폐수의 경우는 값비싼 외부탄소원을 넣어주어야 한다. 따라서 폐수 특성에 맞는 효율적이고 경제적인 질소 화합물 제거 기술의 개발은 불가피하다. 따라서 종속영양탈질공정의 경제성 문제 및 기존의 황탈

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.3
• /
• pp.404-409
• /
• 2012

In order to obtain optimum mixing conditions with animal cadaver residue and sawdust for composting using rendering treatment method for agricultural recycling, changes of chemical characteristics and compost quality after composting were investigated. Initial mixing ratios with animal cadaver residue and sawdust were adjusted 100 : 0, 50 : 50 and 30 : 70. Temperature, pH, contents of ammonia and carbon dioxide were rapidly increased in 3 days and then decreased with time. Organic matter content was similar in all conditions. In mixing ratio of 50 : 50, the compost quality was satisfied with compost depending on official standard for product fertilizer. Thus, the optimum mixing ratio of animal cadaver residue and sawdust were 50 : 50.

• Journal of environmental and Sanitary engineering
• /
• v.24 no.3
• /
• pp.7-15
• /
• 2009

The objective of this study was to investigate difference in nitrogen, organic, phosphorus and $NH_3$-N removal efficiency according to organic loading, comparing M-DEPHANOX process which has two nitrification reactor with M-eBNR process which has one nitrification reactor. As a result of this study, $NH_3$-N removal efficiency of M-DEPHANOX and M-eBNR resulted in average level of 91.8%, 96.9%, respectively. M-DEPHANOX and M-eBNR processes showed high removal efficiency in view of $NH_3$-N removal efficiency. Comparing organic removal efficiency by M-DEPHANOX and M-eBNR processes, the average removal efficiency in terms of TCOD, SCOD was 84.1%, 78.2% and 83.4%, 75.6%. Also, the results that observed about $NH_3$-N removal efficiency regarding organic loading revealed that nitrification reactor of RBC type are little influenced by flowing organic without precipitating at settling tank. Therefore, although inflow characteristics of municipal wastewater changes, M-eBNR process appeared to remove $NH_3$-N reliably.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.3
• /
• pp.151-164
• /
• 2013

Multidimensional dynamic water quality model of organic matter and trophic state was applied to the Han River system. The model was calibrated using field measurement data obtained during the year of 2007. The model results showed reasonable performance in predicting temporal variations of TN, TP, Chl-a and BOD concentrations. The applied integrated modeling system can be effectively used to simulate water quality as well as hydrodynamic and water temperature for river-lake continuous system in the Han River. Utilizing the calibrated model, we analyzed the spatial and temporal distributions of TN, TP, Chl-a and BOD concentrations in the Han River system. The temporal variations of water quality at each river reach and lake were effectively simulated with the developed model and spatial distribution of water qualities in the Han River system could be compared. The multidimensional dynamic modeling system can simulate the water qualities of entire waterbody where Lake Paldang and the incoming flows are included using single modeling system. So it can be effectively used for integrated water quality management of the Han River system.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.5
• /
• pp.553-568
• /
• 2018

Chromophoric Dissolved Organic Matter (CDOM) plays a dominant role in absorbing UV-VIS light and is also important in the biogeochemical carbon cycle due to the production of carbon dioxide from photo-oxidation at the sea surface in marine environments. Since absorption by CDOM was recently found to be responsible for increasing the energy absorbed in the mixed layer by 40 % over pure seawater, the importance of CDOM absorption in seawater for increasing sea surface temperature has come to be well recognized. We measured aCDOM and the absorption characteristics of CDOM during spring 2012 and 2014 in the southwestern East Sea. Distribution of CDOM in spring 2012 and 2014 was compared and S value was used to find the source of CDOM in the study area. As a result, the average $a_{CDOM}$ was $0.237m^{-1}$ ($0.009{\sim}0.988m^{-1}$) and the average S value was $16{\mu}m^{-1}$,which shows coastal properties. Also a positive correlation between Chl a and CDOM was observed ($r^2=0.34$), with an especially strong correlation near coastal stations. aCDOM in 2014 was about 40 % higher than aCDOM in 2012 during spring in the study area. This difference in aCDOM concentration resulted not only from annual variation but also from stratification and photobleaching in late spring 2012. This observation implies the possibility of flux of carbon dioxide into the atmosphere as a result of photo-oxidation in the East Sea.

• Korean Journal of Environmental Agriculture
• /
• v.38 no.3
• /
• pp.119-123
• /
• 2019

BACKGROUND: Estimation of soil nitrogen supply is essential to manage nitrogen fertilization in arable land. In Korea, nitrogen fertilization is recommended based on the soil organic matter content because it is difficult to assess nitrogen (N) mineralization of upland soils directly. In this study, the relationship between soil organic matter (SOM) content and N mineralization was investigated to explore the limitation of using SOM in predicting soil N mineralization. METHODS AND RESULTS: Soil samples from the 0 to 10 cm depth were collected from 18 individual pepper cultivated fields in Tae-an and Chung-yang provinces before fertilization. N mineralization in the soils was quantified using incubation for 70 days at $30^{\circ}C$. The mineralizable soil N (MSN) was positively correlated with SOM, and the relation equation between MSN and SOM was '$MSN(kg\;10a^{-1})=0.2933{\ast}SOM(g\;kg^{-1})+0.0897$ ($r^2=0.6224$, p<0.001)'. However, the differences of N mineralization among the soils with the similar concentrations of soil organic matter were about 3 to 4.6 times, suggesting that the other soil factors such as total N concentration or EC should affect N mineralization. CONCLUSION: We concluded that SOM alone could not reflect the capacity of soil to supply N that is used for recommendation of N fertilization rate. Therefore, other soil properties should be considered to improve N fertilization management in arable land for sustainable agriculture.