• Journal of Korean Society of Environmental Engineers
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• v.33 no.4
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• pp.231-236
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• 2011

The effects of magnesium and calcium ions on phosphorus removal by aluminium coagulation were investigated with various jar tests using settled raw sewage. Maximum TP (total phosphate) removal occurred at pH around 5~6 with aluminium coagulation, and it decreased above pH 6. TP and $H_nPO_4^{n-3}$ removal efficiencies, however, were kept above 95% at pH above 6 by adding the divalent metallic ions like magnesium or calcium ions on aluminium coagulation process. At molar ratio of Al/P ($Al^{3+}/H_nPO_4^{n-3}$) above 3, TP removal efficiency was as high as 80%, and residual TP less than 0.2 mg/L occurred at Al/P ratio above 6. TP removal efficiency was improved by adding magnesium or calcium ions and the optimum $Al^{3+}/Mg^{2+}$ and $Al^{3+}/Ca^{2+}$ ratios were about 2. The required dose of aluminium coagulant was reduced for equivalent amount of TP removal by adding magnesium or calcium ions, as a result sludge generation was also reduced.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.9
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• pp.609-613
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• 2014

The aim of this study was effect of N/P ratio on the nutrient removal in the wastewater using microalgae. For this experiment, 1 to 70 various N/P ratio was prepared and used microalgae as Botryococcus braunii in the wastewater. The results of this study were that 1 to 30 of N/P ratio was need for biomass productivity in the wastewater. TN removal was measured 82% for 1 to 30 N/P ratio and 73-78% for 31 to 70 N/P ratio. TP removal in 1 to 20 N/P ratio was determined up to 80%, but over 21 N/P ratio was decreased significantly and was not changed around 22% of TP removal in the 50 to 70 N/P ratio. Therefore, the optimum N/P ratio in the wastewater was 1 to 30 for biomass productivity, TN and TP removal. The correlation ($R^2$) of TP removal and biomass productivity was 0.9126. However, the relationship between TN removal and biomass productivity was not found. The P content in the wastewater was influenced more than that of TN content.

• Resources Recycling
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• v.17 no.5
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• pp.60-65
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• 2008

A study on the removal of silver(Ag) in copper electrolyte was carried out to produce high purity copper by using various method such as ion exchange resin, activated carbon adsorption, copper cementation with powder and wire, CuS precipitation. Parameters, such as reaction time, reaction temperature, addition amount etc. were investigated to determine the effective condition of silver removal. CuS precipitation and ion exchange using Lewatit TP214 was found to be effective. Especially, silver content in copper electrolyte was reduced from 10 ppm to less than 0.1 ppm by ion exchange with Lewatit TP214.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.1
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• pp.100-109
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• 2012

Removal rates of $PO_4-P$ and TP in a free water surface wetland system were investigated. The system was established in 2008 on a floodplain in the middle reach of the Gwangju Stream flowing through Gwangju City. Its dimensions were 46 meters in length and 5 meters in width. Two year old Typha angustifloria L. growing in pots were planted on half of the area and Zizania latifolia Turcz on the other half in 2008. Stream water was funneled into the wetlands by gravity flow, and its effluent was discharged back into the stream. The influent volume was controlled by valves and water depth was adjusted by wires. Volume and water quality of inflow and outflow were analyzed from January to December in 2010. Inflow into the system averaged approximately $710m^3/day$ and hydraulic residence time was about 1.5 hours. Average influent and effluent $PO_4-P$ concentration were 0.144 and 0.103mg/L, respectively, and $PO_4-P$ abatement amounted to 28.6%. Influent and effluent TP concentration averaged 0.333 and 0.262mg/L, respectively, and TP retention reached to 20.7%.$PO_4-P$ removal rate(%) during plant growing season(31.448) was significantly high(p<0.001) when compared with that during plant non-growing season(25.829). TP abatement rate(%) during plant growing season(27.230) was also significantly high(p<0.001) when compared with that of the non-growing season(14.856). Major phosphorous removals in the system resulted from adsorption of phosphorous in the litter-soil layers; sedimentation of particulate phosphorous and Ca, Al, Fe bounded phosphates; and absorption of phosphorous by emergent plants. The adsorption and sedimentation occurred throughout the year, however, the absorption took place during plant growing season. This resulted in higher removals of $PO_4-P$ and TP during plant growing season.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.381-387
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• 2013

Nitrogen and phosphorus removal was investigated in an UASB-ABF (Up-flow anaerobic sludge blanket - aerated bio-filter) anaerobic sewage treatment system. Successful removal of nitrogen and phosphorus with organic matters was possible in the UASB-ABF system from the results of 160 days operation with the influent raw domestic sewage. Removal efficiencies of organic matter (as TCOD) showed 64% in UASB without recycle of the ABF effluent, however, they increased to 92%, 95%, 96% with 120%, 180% and 240% recycle of the ABF effluent, respectively. Increasement of the organic matter removal was not prominent at recycle ratio above 180%. Apparent increase in TN removal occurred with recycle of the ABF effluent. TN removal efficiency was 18% without recycle, but it increased to 82% with 240% recycle of the ABF effluent. And stable nitrification above 95% was possible as a result of efficient removal of organic matter in the UASB with and without recycle of the effluent. Removal of both TP and $PO{_4}^{3-}$-P also increased remarkably with recycle of the effluent. Without recycle of the effluent, that is at strict anaerobic condition in UASB, TP was not removed, however, its removal efficiency increased to 51%, 63%, 71% at recycle ratios of 120%, 180%, 240%, respectively mainly at UASB.

• Journal of environmental and Sanitary engineering
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• v.12 no.3
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• pp.1-7
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• 1997

이 연구에서는 SBR 공법을 이용하여 질소, 인 동시제거기장에 대해 관찰하고 BOD-SS loading변화에 따른 오염물질 제거효율에 대해 검토하였다. BOD, TN 및 TP 제거율은 $20^{\circ}C$에서 95%, 74% and 81%로 나타났으며, Phosphorus luxury uptake는 호기성이 시작된후 1,2시간후에 각각 67% 및 84%를 흡수 하는 것으로 관찰 되었으며, 호기성 말기의 농도는 $0.9mg/{\ell}$ 이하를 유지하였다. 80% 및 85% 이상의 안정된 질소 제거효율을 유지하기 위해서는 BOD-SS loading 값을 0.15 및 0.08 kg-BOD/kg-SS.day 이하로 유지하여야 하는 것으로 나타났다. 또한 1회 방류수량의 변화에 따른 관찰에서, 반응조 유효용량의 30%, 40% 및 50%를 유출할 경우 TN은 각각 78%, 72% 및 58%를 TP는 각각 81%, 77% 및 66%의 제거효율을 보였다.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.264-270
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• 2003

A quantitative survey of the protozoa microfauna at bioreactor of advanced sewage treatment plant was carried out during a period of 11 months. In this study, 32 genera were identified, including 17 ciliates. The abundance of the important protozoa were compared with the operating parameters and water quality of the effluent of the plant using statistical procedure. Statistical analysis revealed a relationship between the abundance of some genera and removal rate. In particular, correlation analysis on the quality of effluent and protozoa indicated that Lepadella may be used as the bioindicator of TP removal and Trochilia, Entosiphon, Colepus may be used as the bioindicator of TN removal when water temperature was below $20^{\circ}C$.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.153-160
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• 2009

A phytoplankton cultivation system was installed and operated for removal of nutrients from stream water polluted by nonpoint source pollution. The system was a continuous-flow culture comprising a phytoplankton tank that received inflow from a storage reservoir. When the system was operated as a batch culture for the purpose of determining hydraulic retention time (HRT), the proper HRT value was three days, and the removal rate of TP and TN averaged 70% and 44%, respectively. When the system was operated with the continuous flow from a stream for 45 days, 53.9% of TP and 53.1% of TN were removed as sludge. Due to active growth of phytoplankton, pH and dissolved oxygen in the phytoplankton tank were extremely high, reaching 10.8 and 16mg $L^{-1}$, respectively. It was concluded that nutrients can be effectively removed from polluted stream waters by cultivating phytoplankton.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.209-209
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• 2020

환경부 자료에 따르면 1990년대부터 2000년대 후반까지 국내의 도시면적은 696,239㎢ 증가했다. 도시지역에서의 불투수면적이 차지하는 비율은 25% ~ 80%로 적지 않은 비율을 차지한다. 따라서 도시면적이 증가하면 이는 불투수면적의 증가로 이어지며 이로인한 지표유출로 오염물질의 유입이 늘어나게 되면, 수질오염중 비점오염원이 차지하는 비중의 증가한다. 비점오염원으로 인해 발생하는 환경문제를 해결하기 위해 LID(Low Impact Develpment)시설에 대한 연구가 많이 진행되었다. 본 연구에서는 7년간의 선행 연구결과를 바탕으로 LID 시설별 오염물질 저감효율을 비교분석하였다. 용인 삼계리에 위치한 식생수로 오염지표들의 유입, 유출EMC를 토대로 제거 효율에 대한 평가를 해보면 TSS는 46%, BOD는 48%, COD는 56%. TN은 42% 그리고 TP는 58%가 나왔다. 용인 해곡동에 위치한 식생여과대의 경우 TSS는 83%, BOD는 45%, COD는 43%, TN은 39%, 그리고 TP는 62%가 나왔다. 마지막으로 전주에 위치한 식생체류지의 경우 TSS는 100%, BOD는 75%, TOC는 62%, TN은 67% 그리고 TP는 83%가 나왔다. 이들 자료를 바탕으로 효율성 평가를 해보면 먼저 식생수로의 경우 TP 저감 효율이 58%로 가장 높았으며 TN 저감 효율이 42%로 가장 낮았다. 식생여과대의 경우 TSS 저감 효율이 83%로 가장 높았으며 TN 저감 효율이 39%로 가장 낮았다. 마지막으로 식생체류지의 경우 TSS 저감 효율이 100%에 가까운 양질의 제거효율을 보여주었으며, TOC의 경우 67%로 제일 낮은 제거효율을 보였다. 위 결과를 토대로 판단을 해보면 식생체류지가 전반적으로 좋은 지표를 보였으며 대부분의 상황에 양호한 제거효율을 기대할 수 있다고 생각된다. 식생 LID시설은 자연친화적이며 강우유출과 오염물질을 제거할 수 있다는 장점이 있는 반면, 장치형 LID시설에 비해 넓은 부지면적을 필요로 하므로 설치 지역의 특성에 맞게 LID 시설을 시공하는것이 적절하다고 판단된다. 해당 연구결과는 향후 식생형 LID시설을 설계하는데 있어서 기초자료로 반영될 것으로 기대된다.

• Korean Journal of Ecology and Environment
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• v.50 no.2
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• pp.187-194
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• 2017

This study was intended to evaluate the removal efficiency of nutrients in effluents of wastewater using microalgae. Microalgae used in the culture experiment collected in stream and reservoir located in Gyeongsangbuk-do. Dominant species in prior-culture tank were Monoraphidium contortum, Scenedesmus acutus, Coelastrum microporum and Chlorella sp. Dominant species in synthetic wastewater culture under the 4000 Lux and 8000 Lux were Chlorella sp. and Scenedesmus obliquus. The removal efficiency of $NO_3-N$ under the 4000 Lux and 8000 Lux were 27.2%~88.1% and 63.0%~83.6% respectively. The removal efficiency of $PO_4-P$ under the 4000 Lux and 8000 Lux showed above 93%. Removal efficiency of nutrients of $1.0{\times}10^6cells\;mL^{-1}$ inoculation concentration was more higher than that of nutrients of $1.0{\times}10^5cells\;mL^{-1}$ and $1.0{\times}10^7cells\;mL^{-1}$ inoculation concentration. Microalgae cultured in synthetic wastewater removed 94.9% of TN and 90.0% of TP. The removal rate of TN and TP in synthetic wastewater were $1.961mg\;L^{-1}\;day^{-1}$ and $0.200mg\;L^{-1}\;day^{-1}$ respectively. Nutrient removal efficiency of microalgae according to kinds of wastewater showed the highest in the private sewage.