• 한국환경보건학회지
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• 제39권1호
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• pp.83-89
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• 2013

Objectives: The purpose of this experiment was to illuminate the relationship between the phosphorus removal rate of unit operation and the phosphorus removal rate of phosphorus volume loading in the Ferrous Nutrient Removal process, which consists of an anoxic basin, oxic basin, and iron precipitation apparatus. Methods: This study was conducted in order to improve the effect of nitrogen and phosphorus removal in domestic wastewater using the FNR (Ferrous Nutrient Removal) process which features an iron precipitation reactor in anoxic and oxic basins. The average concentration of TN and TP was analyzed in a pilot plant ($50m^3/day$). Results: The removal rate of T-N and T-P were 66.5% and 92.8%, respectively. The $NH_3-N$ concentration of effluent was 2.62 mg/l with nitrification in the oxic basin even though the influent was 17.7 mg/l. The $NO_3$-N concentration of effluent was 5.83 mg/l through nitrification in oxic basin even though the influent and anoxic basin were 0.82 mg/l and 1.00 mg/l, respectively. The specific nitrification of the oxic basin ($mg.NH_3$-Nremoved/gMLVSSd) was 16.5 and specific de-nitrification ($mg.NO_3$-Nremoved/gMLVSSd) was 90.8. The T-P removal rate was higher in the oxic basin as T-P of influent was consumed at a rate of 56.3% in the anoxic basin but at 90.3% in the oxic basin. The TP removal rate (mg.TP/g.MLSS.d) ranged from 2.01 to 4.67 (3.06) as the volume loading of T-P was increased, Conclusions: The test results showed that the electrolysis of iron is an effective method of phosphorus removal. Regardless of the temperature and organic matter content of the influent, the quality of phosphorus in the treated water was both relatively stable and high due to the high removal efficiency. Nitrogen removal efficiency was 66.5% because organic matter from the influent serves as a carbon source in the anoxic basin.

• Fisheries and Aquatic Sciences
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• 제23권6호
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• pp.15.1-15.14
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• 2020

Background: Large rivers are ecological treasures with high human value, but most have experienced decades of degradation from industrial and municipal sewage, row-crop agricultural practices, and hydrologic alteration. We reviewed published analyses of long-term fish diversity publications from three intensively managed large river ecosystems to demonstrate the conservation potential of large river ecosystems. Results: We show how the incorporation of recent advances in river concepts will allow a better understanding of river ecosystem functioning and conservation. Lastly, we focus on the Wabash River ecosystem based on high conservation value and provide a list of actions to maintain and support the ecosystem. In the Wabash River, there were originally 66 species of freshwater mussels, but now only 30 species with reproducing populations remain. Although there were multiple stressors over the last century, the largest change in Wabash River fish biodiversity was associated with rapid increases in municipal nutrient loading and invasive bigheaded carps. Conclusions: Like similarly neglected large river systems worldwide, the Wabash River has a surprising amount of ecological resilience and recovery. For instance, of the 151 native fish species found in the 1800s, only three species have experienced local extinctions, making the modern assemblage more intact than many comparable rivers in the Mississippi River basin. However, not all the changes are positive or support the idea of recovery. Primary production underpins the productivity of these ecosystems, and the Wabash River phytoplankton assemblages shifted from high-quality green algae in the 1970s to lower less nutritional blue-green algae as nutrient and invasive species have recently increased. Our recommendations for the Wabash River and other altered rivers include the restoration of natural hydrology for the mainstem and tributaries, nutrient reductions, mechanisms to restore historical hydrologic patterns, additional sediment controls, and improved local hydraulics.

• Journal of Ecology and Environment
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• 제41권9호
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• pp.235-245
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• 2017

Background: Loading of excess nutrient via bioremediation of polluted sediment to overlying water could trigger anoxia and eutrophication in coastal area. The aim of this research was to understand the changes of overlying water features such as dissolved oxygen (DO); pH; oxidation reduction potential (ORP); $chlorophyll-{\alpha}$ ($Chl-{\alpha}$); and nitrogen nutrients ammonia ($N-NH_4{^+}$), nitrate ($N-NO_3{^-}$), and nitrite ($N-NO_2^-$) when the sediment was not treated (control) and treated by calcium peroxide for 5 weeks. Methods: The water samples were analyzed for measuring physical and chemical properties along with the sediment analyzed by polymerase chain reaction (PCR) including denaturing gradient gel electrophoresis (DGGE) for identifying the phylogenetic affiliation of microbial communities. Results: Results showed that due to the addition of calcium peroxide in sediment, the overlying water exposed the rise of dissolve oxygen, pH, and ORP than control. Among the nitrogen nutrients, ammonia inhibition was higher in calcium peroxide treatment than control but in case of nitrate inhibition, it was reversed than control. $Chlorophyll-{\alpha}$ was declined in treatment column water by 30% where it was 20% in control column water. Actibacter and Salegentibacter group were detectable in the calcium-peroxide-treated sediment; in contrary, no detectable community ware found in control sediment. Both phylogenetic groups are closely related to marine microflora. Conclusions: This study emphasizes the importance of calcium peroxide as an oxygen release material. Interaction with peroxide proved to be enhancing the formation of microbial community that are beneficial for biodegradation and spontaneity of nutrient attenuation into overlying water.

• Journal of Ecology and Environment
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• 제43권1호
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• pp.22-30
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• 2019

Background: Piton du Milieu (PdM) impounding reservoir is suspected to be eutrophic based on the elevated level of orthophosphate and nitrate. Water supplies from three adjacent rivers are primarily thought to contribute to the nutrient enrichment of the reservoir. It is also suspected that there is leaching of orthophosphate, nitrate and organic matter into the rivers during rainfall events and also as a result of anthropogenic activities within the catchment area. The aim of this study was to ascertain the impact of nutrient loading on the water quality of PdM water and on the population of freshwater microalgae in the reservoir. The enumeration and identification of algae from PdM were performed by differential interference contrast microscopy. Dissolved oxygen (DO) and pH were determined by electrometric methods, whereas nutrient levels, silica and total organic carbon (TOC) were determined by instrumentation techniques. Results: Annual mean orthophosphate, nitrate and total organic carbon input from the three feeders within the catchment area of PdM reached levels as high as 0.09 mg/L, 0.4 mg/L and 2.62 ppm respectively. Over a 12-month period, mean TOC concentration in the reservoir was 2.32 ppm while the mean algal cell count was 4601 cells/mL. The dominant algal species identified were Oscillatoria, Cyclotella, Navicula and Cosmarium. Conclusion: This study highlights the trophic state of the reservoir water and clearly points to the need for constant monitoring in order to avoid the occurrence of an impending harmful algal bloom.

• 한국환경과학회지
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• 제14권8호
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• pp.771-775
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• 2005

The purpose of this research was to investigate applicative possibility of field. Pilot-scale experiments were conducted, at outdoor temperature, HRT l0hour, IR(Internal Recycle) $150\%$ and used $2.8m^3$ Reactor. External carbon source was varied 80 to 120 mg/L. When External carbon source and Alkalinity were injected to the B3 pilot plant, the removal efficiencies of COD and BOD were not decreased. Nitrification rate were 5.95, 5.40, 4.08 $mgNH_4^+-N/gSS/d$ during operation periods and denitrification rate was $3.l2mgNO_3^--N/gSS/d.$ When we surveyed the relationship between loading rate of nitrogen and nitrogen removal quantity, this data was 0.949, B3 process will be possible application process of field.

• 한국환경보건학회지
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• 제22권4호
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• pp.49-54
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• 1996

The anaerobic landfill leachate treatment can surmount dilution problem of high concentration landfill leachate, collect methane gas as byproduct, and treat low phosphate concentration leachate because of low nutrient salt requirement. The problems of conventional anaerobic treatment that are requirement of large reactor because of low microbial growth rate(HRT=20-30 days) and low volumetric loading rate(VLR=0.5-2.0 kg $COD/m^3\cdot day$) are able to surmount by introduction of high rate anaerobic treatment. In this study, the upflow blanket filter(UBF) which is high rate anaerobic process was applyed to the landfill leachate treatment. The acceptable volumetric loading rate and HRT were 18.23 kg $SCOD/m^3\cdot day$ and 13 hrs. SCOD removal rate was over 90% at VLR 18.23 kg $SCOD/m^3\cdot day$. The methane gas yield was $0.15 lCH_4/g$ SCOD added(at STP) at VLR 18.23 kg $SCOD/m^3\cdot day$. The solids accumulation yield was 0.40 g VSS/g COD removed.

• 환경생물
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• 제24권3호
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• pp.230-239
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• 2006

본 연구는 2002년 1월부터 2003년 5월까지 오염원이 비교적 단순한 산지하천에서의 무기 영양염 및 유기물 변동을 고찰하기 위해 낙동강 지류인 대천천의 상류에서 실시되었다. 조사지점은 인위적인 오염이 없는 DC1, 주위의 식당과 민가에서 생활하수가 유입되는 DC2, DC3, DC4그리고 부분적으로 수질이 자연 정화된 DC5이다. 전기전도도, 탁도, BOD는 하수의 유입으로 인하여 DC2에서 급격히 증가하였다가 DC5에서 다시 낮아졌다. 수층의 $NH_4^+$및 $PO_4^{3-}$농도는 갈수기인 겨울에 증가하는 경향이 보였으며, DC2에서 DC1에 비해 각각 150 배 및 37배가 증가하였다가 하류로 내려 갈수록 뚜렷하게 감소하였으며, $NO_3^-+NO_2^-$은 오염지역인 DC2, DC3, DC4와 DC5에서 청정지역인 DC1보다 약 2배 증가하였다. N/P비율은 DC1에서 가장 높았고, 하수 유입지역에서 감소하여 이들 지역에는 부영양화가 진행되고 있음을 알 수 있었다. 퇴적물 공극수의 $PO_4^{3-}$농도는 겨울과 봄에 증가하였으나, $NH_4^+$와 $NO_3^-+NO_2^-$의 농도는 계절 경향이 보이지 않았다. 퇴적물 공극수의 $NO_4^-,\;PO_4^{3-}$ 농도와 퇴적물의 유기물 함유량도 하수가 유입되는 DC2, DC3, DC4에서 유의하게 증가하였고, DC5에서 다소 감소하였다. 퇴적물 공극수의 $NO_3^-+NO_2^-$의 농도는 DC2에서보다 용존산소가 풍부한 DC5에서 오히려 증가하였다. 수층의 TOC와 DOC농도는 봄과 가을에 증가하였고, 하수가 유입되는 지역에서 높게 측정되었다. 조사지역이 산지하천의 상류에 위치하고 있으나 식당 및 민가에서 유입되는 생활하수는 하천의 상류를 부영양화 시켰으며, 하류로 내려오면서 유기물 및 무기 영양염의 농도가 감소하여 하천수가 자연적으로 정화되는 것이 관찰되었다.

• Journal of Animal Science and Technology
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• 제49권2호
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• pp.279-286
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• 2007

반응물을 연속적으로 내부 순환시키는 생물막 연속회분식모래여과 공정을 고안하고 외부 탄소원이 전혀 사용되지 않는 조건하에서의 돈사폐수 처리특성을 평가하였다. 수직형과 경사형 모래여과조에서의 NOx-N 부하량에 따른 탈질율은 각각 19%와 3.8%로 수직형에서 5배 정도 높은 효율을 보임에 따라 수직형태의 모래여과조를 생물막 연속회분식 공정과 연계하여 운전하였다. 처리공정을 HRT 15일, 내부순환율 105L/hr.m3, 평균 암모니아성 질소 부하량 54g/m3.d 조건에서 운전하였을 때 STOC, NH4- N, TN의 처리효율은 각각 75%, 97%, 85%이었다. 생물막 연속회분식 반응조와 모래여과조간의 내부순환으로 TN의 제거효율이 약 14%증진되는 것으로 나타났으며 얻어진 질소제거효율 증진은 주로 모래여과조에서의 탈질에 의한 것으로 밝혀졌다. 또한 용해성 인의 경우 내부순환이 수행되지 않았을 시에는 유출수내 농도가 오히려 증가하였으나 내부순환시에는 약 57% 정도가 제거되는 것으로 나타남에 따라 반응물의 내부순환이 용해성 인의 제거효율 증진에도 기여함을 알 수 있었다. 시스템에서의 질소제거 양상을 분석해본 결과 최종 유출수내의 NH4-N은 부하량 60g/m3.d 수준에서 약 20mg/L 이하로 비교적 일정하였고 부하량이 100g/m3.d. 이상의 수준으로 상승함에도 80% 이상의 질소 제거효율을 보였다. 그러나 부하량 100g/m3.d 수준 이상에서부터 처리효율이 감소하는 것으로 나타나 외부탄소원이 전혀 사용되지 않는 운전조건에서의 질소의 적정 부하량은 약 100g/m3.d 정도인 것으로 판단되었다.

• 한국해양환경ㆍ에너지학회지
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• 제1권2호
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• pp.96-108
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• 1998

대표적인 부영양화 해역인 일본의 뢰호내해를 대상으로 하여 해수ㆍ저질문의 욕존 산소와 영양염의 수수과정을 표현할 수ㆍ저질예측모델을 개발하여, 해역의 유입부하량과 수질의 응답특성, 부하량삭감의 영향해석 및 유입부하량과 수산자원의 관계 해석을 통하여 부영양화 해역의 수질관리방안에 대하여 연구하였다. 부하에 대응한 수질의 장기예측결과, 부하량과 수질의 응답특성이 해역에 따라 다르게 나타난다. 적상부하량의 간역추산방법으로서 인접해역의 부하영향 및 기여율을 포함한 부하삭감후의 수질예측에 대한 개산식을 제안하였다. 부하량 삭감효과의 수직계산결과 인(P) 뿐만 아니라 질소(N)의 부하삭감의 영향이 크게 기여함을 보였다. 유입부하량과 수산자원의 관계를 수질을 매개로 검토한 바, 뢰호내해와 같은 부영양화 해역에서는 유입부하량의 증가는 1차생산량의 증가에 반영되지만 2차생산 이후의 전송효율에도 한도가 있는 것으로 나타났다.

• 한국환경보건학회지
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• 제31권4호
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• pp.235-240
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• 2005

The effects of municipal sewage treatment plants on the water quality and effluent loading were investigated. BOD removal rates from Wonju, Hoengseong, and Hongcheon municipal sewage treatment plants were $88.9\%,\;80.6\%,\;90.7\%$ and T-P removal rates were $47.3\%,\;56.5\%,\;71.6\%,$ respectively. Also, BOD effluent leading from WonJu, Hoengseong, and Hongcheon treatment plants were 1,520 kg/day, 75 kg/day, 55 kg/day and T-P effluent loading were 203.9 kg/day, 4.2 kg/day, 4.0 kg/day, respectively. In terms of water quality distribution by distance of flow, BOD of the Seom river rapidly rose from 1.6 mg/l to 4.0 mg/l and T-P rose from 0.034 mg/l to 0.321 mg/l. Also BOD of the Hongcheon river showed a slowly rise from 1.1 mg/l to 1.4 mg/l and T-P from 0.011 mg/l to 0.026 mg/l. In conclusion, the effects of municipal sewage treatment plants on the water quality proved that T-P was higher than BOD. Consequently, in order to improve water quality, it is necessary to adopt an advanced sewage treatment system like nutrient removal.