• Environmental Engineering Research
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• 제21권3호
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• pp.276-283
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• 2016

The goal of this study was to evaluate the effect of effluents from conventional activated sludge (CAS) and biological nutrient removal (BNR) processes on algal bloom in receiving waters. We made multiple effluent sampling from one CAS and two BNR facilities, characterized their effluents, and conducted bioassay using river and ocean water. The bioassay results showed that CAS effluents brought similar productivity in both river and ocean water, while BNR effluents were more reactive and productive in ocean water. Unexpectedly, nitrogen-based biomass yields in ocean water were up to six times larger for BNR effluents than CAS effluent. These results indicated that nitrogen in BNR effluents, although its total concentration is lower than that of CAS effluent, is more reactive and productive in ocean water. The ocean water bioassay further revealed that effluents of BNR and CAS led to considerably different phytoplankton community, indicating that different characteristics of effluents could also result in different types of algal bloom in receiving waters. The present study suggests that effects of upgrading CAS to BNR processes on algal bloom in receiving waters, especially in estuary and ocean, should be further examined.

• 한국세라믹학회지
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• 제54권2호
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• pp.108-113
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• 2017

The use of aluminum-based coagulants in water pretreatment is being carefully considered because aluminum exposure is a risk factor for the onset of Alzheimer's disease. Lightly burned-dolomite kiln dust (LB-DKD) was evaluated as an alternative coagulant because it contains high levels of the healthful minerals calcium and magnesium. An organic pore forming agent (OPFA) was incorporated to prepare porous granules after OPFA removal through a thermal decomposition process. A spray drying method was used to produce uniform and reproducible spherical granules with low density, since fine dolomite particles have irregular agglomeration behavior in the hydration reaction. The use of fine dolomite powder and different porosity granules led to a visible color change in raw algae (RA) containing water, from dark green to transparent colorlessness. Also, dolomite powders and granules exhibited a mean removal efficiency of 48.3% in total nitrogen (T-N), a gradual increase in the removal efficiency of total phosphorus (T-P) as granule porosity increased. We demonstrate that porous dolomite granules can improve the settling time and water quality in summer seasons for the emergent treatment of excessive algal blooms in eutrophic water.

• 자원환경지질
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• 제36권6호
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• pp.557-561
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• 2003

적조구제효율이 높고 환경 친화적으로 적조를 방제시킬 수 있는 물질을 개발하기 위해 점토광물, 철 광물 및 제올라이트 등 단일광물에 대해 구제효율을 측정하였고, 그 결과를 황토와 비교하였다. 실험 조건은 해수와 각 광물의 분말을 10g/${\ell}$의 비율로 혼합 살포하였으며, 코클로디니움의 개체수가 $m{\ell}$ 당 3,000∼5,000 셀을 유지하는 조건하에서 10분, 30분, 60분이 경과한 후, 활동성 있는 적조생물의 개체수를 계수하였다. 측정결과, 일라이트, 캐올리나이트, 몬모릴로나이트 등의 점토광물과 적니, 합성제올라이트는 코클로디니움에 대한 구제효율이 84-92%범위로써 ‘황토’와 유사하였다. 비정질체와 적철석은 투입 30분 경과 후 구제효율은 99%에 달함으로써 가장 높은 구제효율을 나타내었다. 또한 적조구제효율은 대상물질의 화학조성과 pH에 무관하였으며 입도가 3∼50${\mu}m$ 범위일 때는 ‘황토’와 유사하지만 나노크기일 때는 탁월하였다. 위의 실험결과로부터 적조구제제로서 광물질을 사용할 때, 적조구제의 주요 매카니즘은 접촉 및 응집작용으로 판단되며 따라서 구제효율은 적용되는 물질의 비표면적에 정비례한다는 것을 지시한다.

• 미생물학회지
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• 제45권4호
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• pp.362-367
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• 2009

대청호의 한 지류인 소옥천으로부터 고효율 조류억제 세균을 분리하기 위하여 176균주를 분리 스크린하였으며, 이 중 AJ1이 가장 높은 조류성장억제능을 나타내었다(지름 50.0 mm 성장억제환). 조류성장억제능이 높았던 AJ1 균주 동정을 위하여 형태학적, 생리 생화학적, 16S rRNA gene sequence 분석, 지방산 분석을 수행하였으며 그 결과, Pseudomonas aeruginosa 로 판별되었다. AJ1 배양액을 원심분리한 후 상등액을 조류배양액에 첨가 시, 상등액에 의한 조류성장억제능이 나타남에 따라 세포 외 물질 분비에 의한 것을 확인할 수 있었다. 가장 높은 조류성장억 제능[60.2(${\pm}$1.3)%]은 탄소원으로 mannitol을 사용하고, 온도 $30^{\circ}C$, pH 8에서 배양할 때 보였다. 또한, AJ1 균주의 배양기간 및 투여시기에 따른 조류성장억제능 평가 결과, 조류 성장 초기 단계에 조류성장억제균을 투여하였을 때 조류성장억제능이 높게 나타났고, 균주의 배양기간에 따른 조류성장억제능은 연관성이 나타나지 않았다. 상등액 접종량에 따른 조류성장억제능은 상등액의 접종량이 높아질수록 M. aeruginosa의 제거량은 증가하였으며, 고농도(40ml/L)로 적용하였을 때 80.3(${\pm}$8.6)%의 가장 높은 M. aeruginosa 제거효율을 보여주었다. 제거 속도의 경우 상등액 접종량이 낮아질수록 M. aeruginosa 제거율이 높아지는 경향을 확인하였으며, 저농도(10 ml/L)로 적용시 $8.2{\mu}g$ chl-a/supernatant ml/day로 가장 높게 나타났다. 본 연구 결과, AJ1 균주의 현장 적용 시 M. aeruginosa의 제어에 효율적일 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제23권10호
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• pp.1472-1477
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• 2013

Microalgae have been regarded as a natural resource for sustainable materials and fuels, as well as for removal of nutrients and micropollutants from wastewater, and their interaction with bacteria in wastewater is a critical factor to consider because of the microbial diversity and complexity in a variety of wastewater conditions. Despite their importance, very little is known about the ecological interactions between algae and bacteria in a wastewater environment. In this study, we characterized the wastewater bacterial community in response to the growth of a Selenastrum gracile UTEX 325 population in a real municipal wastewater environment. The Roche 454 GS-FLX Titanium pyrosequencing technique was used for indepth analysis of amplicons of 16S rRNA genes from different conditions in each reactor, with and without the algal population. The algal growth reduced the bacterial diversity and affected the bacterial community structure in the wastewater. The following in-depth analysis of the deep-sequenced amplicons showed that the algal growth selectively stimulated Sphingobacteria class members, especially the Sediminibacterium genus population, in the municipal wastewater environment.

• 기계와재료
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• 제10권3호통권37호
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• pp.54-62
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• 1998

• 환경위생공학
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• 제16권3호
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• pp.22-27
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• 2001

It have been investigated how algal and bacterial symbiotic reaction influences on removal of organic carbon in river ecosystem. And artificial experimentation apparatus was made for algae'and bacteia'culture as lab scale. Investigating and researching minutely the change of concentration of organic carbon substrate and the change of population density of algae'and of bacteria'with this artificial experimentation apparatus, the next results could be obtained. 1. Successful decrease of DOC(dissolved organic carbon) could not be expected unless algal and bacterial biomass floe was nut formed effectively and unless biosorption was not proceeded effectively in the very culture system in which artificial synthetic wastewater was supplied continuously at constant rate. 2. In conditions of culture liquid of 1335 glucnse mg/L(type 1) and of 267 glucose mg:L(type 2), the algal dominant species was always Chlorella vulgaris in both types in which artificial synthetic wastewater were supplied continuously at constant rate and algae population density was around maximum 107 cells/mL. 3. It was around 108 ~ 107 cells/mL that the population density of heterotrophic bacterium. In culture medium systems type 1 and type 2 in which artificial wastewater were supplied continuously at constant rate, the same density appeared initially when using the population density of Escherichia coli w 3110 as indirect indicator. And this density decreased rapidly till the culturing date 35 days were passed away, while this density increased with gentle slope after same date and then the trend of change at type 2 was more severe than one at type 1. 4. When seeing such a change of population density of Escherichia coli w 3110, the growth of heterotrophic bacterium appeared as survival instinct pattern of broader requirement of nutrient at condition of low concentration of organic carbon substrate than condition of high concentration of same substrate.

• ALGAE
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• 제17권3호
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• pp.195-199
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• 2002

We investigated the association of Chlorella vulgaris and E. coli W9110 in removal of total organic carbon with the lab-scaled continuous river water flow system (CRWFS). Artificial wastewater was applied at two levels of organic carbon concentration; 1,335 $mg{\cdot}l^{-1}$ in the treatment (T)-1 and 267 $mg{\cdot}l^{-1}$ in T-2. The highest densities of C. vulgaris were $8.3{\times10^6\;cells{\cdot}ml^{-1}$ in T-1 and $6.9{\times}10^6\;cells{\cdot}ml^{-1}$ in T-2. The maximum densities of E. coli W3110 were $2.0{\times}10^8$ clony forming unit (CFU)${\cdot}ml^{-1}$ in T-1 and $3.9{\times}10^8\;CFU{\cdot}ml^{-1}$ in T-2. The densities increased during the first 11 days in T-q and 4 days in T-2, and decreased rapidly till 35th day, then increased slightly afterwards. This trend was prominent in T-2. It was inplied that wider range of nutrients was required in the growth of heterotrophic bacteria in T-2 than in T-1. The algal biomass should be increased effectively for the successful removal of organic carbon.

• 생태와환경
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• 제40권4호
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• pp.537-545
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• 2007

The heavy metal removal capacity of filamentous green alga Cladophora sp. cultured together with wet-mixed solidified soil (loess) was tested. A Cladophora sp. was cultured for 5d, with added Chu No. 10 medium, in stream water contaminated by high concentration of heavy metals from a closed mine effluent. Heavy metal ion concentrations of the medium and in algal tissue were measured every day during the experiment. Dissolved metals (Al, Cd, Cu, Fe, Mn, Zn) in medium were rapidly removed (over 90% elimination) within 1-2d when alga and loess were added. Dissolved heavy metals dropped by only 10% when algae were cultured without loess. The Cladophora sp. accumulated much more heavy metals when cultured with loess than when the alga was cultured alone. Cladophora sp. exhibited a maximum uptake capacity for Al ($17,000{\mu}g^{-1}$ algal dry weight). The metal bioremoval capacities of the algae were in the order Al, Fe, Cu, Mn, Zn and Cd. The heavy metal removal capacity of Cladophora sp. showed significant increases when wet-mixed solidified soil was added to culture media.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권4호
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• pp.221-224
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• 2002

Biomass of non-viable and dried brown marine algae Ecklonia radiata Turn. was used to examine Its cadmium uptake capability. Twelve different pretreatments on the algal biomass were prepared. Among these pretreatments, the algal biomass, which treated with 0.1 M NaOH and kept in water. bath (100$\^{C}$, 18 h) followed by washing with distilled water and squeezing, showed the highest amount of cadmium uptake as 1634 $\pm$ 195 mg/g dry biomass at pH 4.0 and 50$\^{C}$. Adsorption temperatures and pH levels played some Important role In cadmium uptake. However, cadmium uptake decreased dramatically at a lower pH than 4.0. Freundlich adsorption isotherm showed potent cadmium uptake capacity of the non-viable biomass. Pretreatments on the non-viable algal biomass shown in this study nay enhance the Eadmium removal in the industrial wastewater.