• ALGAE
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• 제33권4호
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• pp.329-340
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• 2018

The present study was to determine the effects of salinity on the growth and nutrient bioextraction abilities of Gracilaria and Ulva species, and to determine if these seaweeds can be used for nutrient bioextraction under hypo- and / or hyperosmotic conditions. Two Gracilaria species, G. chorda and G. vermiculophylla, and two Ulva species, U. prolifera and U. compressa, were cultured at various salinity conditions (5, 10, 15, 20, 30, 40, and 50 psu) for 3 weeks. Results showed that the growth rates, nutrient uptake, tissue nutrient contents and nutrient removal were significantly affected by salinity and species. All four species were euryhaline with the highest growth rates at 20 psu. Among the four species, U. prolifera, U. compressa, and G. vermiculophylla showed potential to be used for nutrient bioextraction in estuaries and / or land-based fish farms due to their rapid growth, high nutrient uptake, high tissue carbon and nitrogen accumulation and removal capacities.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2009년도 춘계학술발표회
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• pp.145-147
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• 2009

Nutrients in wastewater should be removed prior to release in the receiving waters to prevent the occurrence of eutrophication. In this study, seawater is used to remove ammonia and phosphate by the formation of struvite ($MgNH_{4}PO_{4}{\cdot}6H_{2}O$). It aims to know the optimum conditions for the removal of nutrients using seawater as source of magnesium ions. Experiments were performed using jar tester and pH of ammonium-phosphate solutions were adjusted Samples were drawn at different mixing times. It was shown that simultaneous removal of ammonia and phosphate is rapid, with no significant reduction beyond 10 min of mixing Another important parameter is pH, where range 10-11 showed the optimum nutrient removal. Increase in the volume of seawater, which meant an increase in magnesium ions also lead to better removal.

• 한국환경보건학회지
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• 제30권2호
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• pp.84-91
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• 2004

Biological nutrient removal(BNR) from wastewater was performed by adopting various process configurations. The simultaneous biological organics, phosphorus and nitrogen removal of synthetic wastewater was investigated in a sequencing batch biofilm reactor (SBBR). The other reactor was operating as a reference, without biofilm being added. The cycling time in SBR and SBBR was adjusted at 12 hours and then certainly included anaerobic and aerobic conditions. Both systems has been operated with a stable total organic carbon(TOC), nitrogen and phosphorus removal performance for over 90 days. Average removal efficiencies of TOC and total nitrogen were 83% and 95%, respectively. The nitrification rate in SBR was higher than that in SBBR. On the contrary, the denitrification rate in SBBR was higher than that in SBR. The phosphorus release was occurred in SBBR, however, not in SBR because of the inhibition effect of NO$_3$$^{[-10]}$ .

• 한국해양학회지:바다
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• 제9권4호
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• pp.153-163
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• 2004

In order to estimate the nutrient flux of the Seomjin River into the coastal waters of South Sea, and to understand the estuarine reactions during mixing between river water and seawater, we collected surface water along the salinity gradient in the Seomjin River estuary from Mar. 1999 to Apr. 2001. We found that nitrate and silicate were delivered by fluvial input, while phosphate was, supplied from disposed wastes in the Gwangyang Bay. Mean annual flux of dissolved inorganic nitrogen (DIN), phosphate and silicate into the Gwangyang Bay was estimated 10.9 molesㆍsec$^{-1}$(4,820 tonnesㆍyr$^{-1}$), 0.07 molesㆍsec$^{-1}$(68 tonnesㆍyr$^{-1}$), 13.3 molesㆍsec$^{-1}$(11,747 tonnesㆍy$^{-1}$), respectively. An evident removal of phosphate, silicate and ammonium at the mid-salinity zone during the dry season was attributed to the active uptake of phytoplankton, and consequently nutrient flux into the Gwangyang Bay was low. Whereas, during the flood season in summer, conservative or additional distribution of the nutrients was observed in the estuary. As a rsult nutrient flux into the Gwangyang Bay was maintained high. High concentrations of chlorophyll a and the active removal of nutrient during the dry season at the mid-salinity zone suggest that nutrient distribution in the Seomjin River estuary was mainly controlled by biological processes and nutrient fluxes into the Gwangyang Bay might be significantly modified of by the primary production.

• 한국물환경학회지
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• 제22권3호
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• pp.444-450
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• 2006

This study was carried out to compare the performance of two types of sequencing batch biofilm reactors (SBBRs), anoxic-oxic-anoxic-oxic $(AO)_2$ SBBR and anoxic-oxic-anoxic $A_2O$ SBBR, on the biological nutrient removal. The TOC removal efficiency in $A_2O$ SBBR was higher than that in $(AO)_2$ SBBR. At the 1st non-aeration period, the release of ${PO_4}^{3-}-P$ in $A_2O$ SBBR was higher than that in $(AO)_2$ SBBR because of the high TOC removal. At the 1st aeration-period, the nitrification was not completed in $(AO)_2$ SBBR, however, it was completed in $A_2O$ SBBR and the nitrification rate in $A_2O$ SBBR was higher than that in $(AO)_2$ SBBR. The release and uptake of ${PO_4}^{3-}-P$ in $A_2O$ SBBR was much higher than in $(AO)_2$ SBBR. Also, the profiles of DO and pH in reactors were used to monitor the biological nutrient removal in two SBBRs. The break point in DO and pH curves at the aeration period coincided with the end of nitrification.

• 상하수도학회지
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• 제27권5호
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• pp.561-570
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• 2013

There are two types of rectangular secondary clarifier at biological nutrient removal (BNR) facility to settle MLSS; conventional activated sludge secondary clarifier and Gould Type I clarifier. In this study, the performances of two types at respective biological nutrient removal facility are compared using weekly operational data. Surface Overflow Rate (SOR), Surface Loading Rate (SLR), Sludge Volume Index (SVI), secondary effluent SS concentration are studied. It has found that Gould Type I has 3.5 times less average secondary effluent SS concentration that is 2.4 mg/L than that of conventional activated sludge secondary clarifier. Both SOR and SLR have shown little effect on secondary effluent SS concentrations at Gould Type I clarifier in contrary that SOR affects the secondary effluent SS concentrations at conventional activated sludge rectangular secondary clarifier. From this study, it is recommended that Gould Type I must be considered for secondary clarifier when BNR plant is designed.

• 한국환경과학회지
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• 제20권1호
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• pp.35-47
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• 2011

The effect of the variation of aeration time on the removal of organics, nitrogen and phosphorus using synthetic wastewater was investigated in sequencing batch reactors (SBRs) which included DNPAOs and DNGAOs. The cycling times in four SBRs were adjusted to 12 hours and then included different aerobic times as 1 hr, 2.5 hr, 4 hr and 5.5 hr, respectively. Four SBR systems have been operated and investigated for over 40 days. Average TOC removal efficiencies were about 71 % in all SBRs. The $NH_4^+$-N removal efficiency was increased as the increase of aeration time. After changing aeration time, the total nitrogen removal efficiencies of SBRs were shown as 35 %, 85 %, 75 % and 65 %, respectively. Higher phosphorus release and uptake were occurred as the decrease of the aeration time. After all, the overall phosphorus removal efficiency decreased and the deterioration of phosphorus removal was occurred when aeration time was over 4 hr. Denitrification in aerobic conditions was observed, which showed the presence of DNPAOs and DNGAOs. In batch experiments, PAOs were shown as the most important microorganisms for the phosphorus removal in this experiment, and the role of DNGAOs was higher than that of DNAPOs for the nitrogen removal.

• 생물환경조절학회지
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• 제26권4호
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• pp.393-401
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• 2017

쌈채소 수경재배 시 문제가 되는 체내 질산염 함량을 효과적으로 저감시키기 위해 폐쇄형 생산시스템에서 1) 저광도($100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$내외) 조건에서의 수확 7일 전 양액조성 방법과 2) 질산염 저감을 위한 적정 광도 및 수확 전 적정 양액결제시기를 구명하기 위해 수행하였다. 청치마상추에서 수확 7일 전 양액조성 방법 중 양액결제(양액공급 중단) 처리와 양액내 질소 공급원으로 탄산암모늄[$(NH_4)_2CO_3$]을 사용한 처리는 처리기간 동안 체내 질산염 함량을 감소시켰으나, 생체중, 엽면적 등의 생육량도 감소되었다. 하지만 $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$조건에서 수확 7일전 양액내 $NO_3-N$ 비료를 결제하여 조성하거나 배양액 농도를 1/2배액으로 낮추어 공급함으로써 외적품질 및 생육량의 저하없이 질산염 함량은 감소되었다. 또한 수확 전 양액결제시기 및 적정 광도를 구명하기 위해 실험을 수행한 결과, 100, 200, 및 $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$의 3수준의 광조건 모두 수확 7일 전 양액결제시에 체내 질산염이 가장 낮게 나타났으며, 특히 $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$의 광도와 수확 7일 전 양액결제 처리시 식물체내 질산염의 빠른 저감효과를 볼 수 있었으나 생육량의 감소를 가져왔다. 수확 3일 전 양액결제 처리에 의해 $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ 광도에서 체내 질산염 함량은 2,021ppm에서 480ppm로, $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ 광도에서 3,018ppm에서 1,035ppm로 감소되었으며, 외적 품질의 저하 없이 생육량이 높으면서 동시에 짧은 시간 동안 식물체내 질산염의 저감 효과를 볼 수 있었다. 수확 7일 전 양액결제 처리는 체내 질산염의 저감효과가 컸던 반면 엽중, 엽면적 등의 생육 감소를 가져왔는데, 200과 $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$의 광조건에서 수확7일 전 양액결제시 수확 3일 전 양액결제보다 엽중은 20~35%, 엽면적은 16~31% 낮은 값을 나타내었다. 광도 및 양액결제시기에 따른 비타민 C 함량을 분석한 결과 100, 200보다 $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ 에서 수확 3일과 5일전 양액결제 처리시 비타민 C 함량이 가장 높게 나타났다.

• Environmental Engineering Research
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• 제21권4호
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• pp.401-408
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• 2016

The aim of this study was to evaluate the biomass and lipid production of Chlorella vulgaris and its nutrient removal capability for treatment of brewery wastewater effluent. The results indicate that the maximum biochemical oxygen demand (BOD) (91.43%) and chemical oxygen demand (COD) (83.11%) were removed by C. vulgaris with aeration in the absence of light. A maximum of 0.917 g/L of dry biomass was obtained with aeration in the dark conditions, which also demonstrated the highest amount of unsaturated fatty acids at 83.22%. However, the removal of total nitrogen (TN) and total phosphorus (TP) with these aeration and light conditions was 9.7% and 11.86% greater than that of other conditions. The removal of BOD and COD and the production of biomass and lipids with aeration in the dark and the TN and TP removal with aeration and light were more effective than other conditions in the brewery wastewater effluent in the presence of C. vulgaris.

• 한국물환경학회지
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• 제18권3호
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• pp.237-243
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• 2002

The effect of a salinity on the performance of a biological nutrient removal system was investigated using a model SBR(Sequencing Bach Reactor) system. The system was operated at a 12hr, 18hr, 24hr, and 36hr HRT with a salinity level of 20,000mg/L and compared with a system similarly operated with fresh water. The influent salinity level of 8,000 mg/L does not have a significant effect on BOD removal efficiency, there is a noticeable decrease in BOD removal rate from 10,000 mg Cl-/L. The Nitrogen could be removed from the saline wastewater with the same efficiency as for the fresh water because of low C/N ratio in anoxic period. The excess biological phosphorous removal is highly affected by the increase in the influent salinity. The efficiency is decreased from 96.6% to 43.4% when the influent salinity is increased from 0 to 20,000mg/L.