• Environmental Engineering Research
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• 제20권1호
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• pp.99-104
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• 2015

The purpose of this study is to evaluate the performance of forward osmosis (FO) system for harvesting microalgae cultivated in secondary sewage effluent. Microalgae species used in this study were chlorella sp. ADE4. The drawing agents used for forward osmosis system were seawater and concentrate of sea water reverse osmosis (SWRO) system. Chlorella sp. ADE4 cultured in secondary sewage effluent illustrated moderate efficiency in removal of total nitrogen (TN) (68%) and superior performance in total phosphorus (TP) removal (99%). Comparison of seawater and SWRO concentrate as drawing agent were made in FO membrane separation of the microalgae. The result from this study depicts that SWRO concentrate is strong drawing agent in FO membrane system providing an average dewatering rate of $4.8L/(m^2{\cdot}hr)$ compared to seawater with average dewatering of $2.9L/(m^2{\cdot}hr)$. Results obtained from this study indicated that FO system could be viable option for harvesting the microalgae for further biodiesel production. SWRO concentrate as a drawing agent could be very important finding in field of membrane technology for disposal of SWRO concentrate.

• 한국패류학회지
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• 제25권1호
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• pp.35-40
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• 2009

The trumpet shell Charonia sauliae is an endangered and valuable species with potential for aquaculture. For artificial propagation of C. sauliae, the effects of three different food microalgae on the development, growth, and survival rate of the larvae and spat were investigated. For the larval feeding experiments, we utilized six microalgae species as food sources, namely Pavlova lutheri, Tetraselmis suecica, Nannochloris oculata, Isochrysis galbana, Chaetoceros calcitrans, and Phaeodactylum tricornutum; for the larval and spat growth and survival experiments, we utilized T. suecica, C. calcitrans, and P. tricornutum. The results showed that the temporal digestion index (TDI) for the veliger larvae was significantly different for C. sauliae fed the different microalgae species (p < 0.05), that the T. suecica, C. calcitrans, and P. tricornutum cultivars were better suited for larval consumption (p < 0.05), and that the growth and survival of the larvae and spat were significantly influenced by food type, specifically P. tricornutum (p < 0.05). Further research is needed to evaluate the effects of other microalgae species, different algal concentrations, and biochemical composition on the growth and survival of C. sauliae.

• 한국양식학회지
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• 제5권1호
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• pp.81-91
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• 1992

해산동물의 종묘생산시 초기단계의 먹이로써 미세조류의 배양은 매우 중요하다. 그러나 자연으로부터 먹이생물로써 필요한 미세조류를 순수분리하여 순종을 보관하는 일은 일반 양식 업자나 이 분야에 종사하지 않는 연구자에게는 매우 어려운 일이다. 따라서 미세조류를 필요로 하는 사람들에게 순종의 미세조류 strain을 공급할 수 있는 은행의 설립이 필요하다. 본 연구에서는 capilla교 pipette법, 한천도말법, 희석법을 이용하여 한국연안에서 80종의 미세조류를 분리하였다. 현재 부산수산대학교 양식학과 실험실에서 확보 배양중인 117종의 미세조류의 배양현황을 보고하였다.

• International journal of advanced smart convergence
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• 제5권2호
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• pp.18-23
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• 2016

Cell walls of microalgae consist of a polysaccharide and glycoprotein matrix providing the cells with a formidable defense against its environment. Anaerobic digestion (AD) of microalgae is primarily inhibited by the chemical composition of their cell walls containing biopolymers able to resist bacterial degradation. Adoption of pre-treatments such as thermal, thermal hydrolysis, ultrasound and enzymatic hydrolysis have the potential to remove these inhibitory compounds and enhance biogas yields by degrading the cell wall, and releasing the intracellular algogenic organic matter (AOM). This paper preproposal stage investigated the effect of different pre-treatments on microalgae cell wall, and their impact on the quantity of soluble biomass released in the media and thus on the digestion process yields. This Paper present optimum approach to degradation of the cell wall by ultra-sonication with practical design specification parameter for ultrasound based pretreatment system. As a result of this paper presents, a microalgae system in a wastewater treatment flowsheet for residual nutrient uptake can be justified by processing the waste biomass for energy recovery. As a conclusion on this result, Low energy harvesting technologies and pre-treatment of the algal biomass are required to improve the overall energy balance of this integrated system.

• Membrane and Water Treatment
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• 제9권3호
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• pp.147-153
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• 2018

This study investigates the role of microbial extracellular polymeric substances (EPSs) as bioflocculants to harvest microalgae (water-microalgae separation). The EPS extracted from waste activated sludge (WAS) by heat extraction were fractionated into soluble EPS (S-EPS), loosely-bound EPS (LB-EPS) and tightly-bound EPS (TB-EPS) forms. All the EPSs facilitated the flocculation of microalgal cells from stable growth medium. Of those EPSs, the TB-EPS showed the highest flocculating activity (FA) resulting in the substantial decrease in the amount of EPS added in terms of total organic carbon (TOC) during flocculation. The FA of microalgae was improved with the increase in TB-EPS dose, however, excessive dose of TB-EPS adversely affected it due to destabilization. Both LB- and TB-EPS could be utilized for flocculating microalgae as a sustainable option to the existing chemical-based flocculants. In addition to the conventional assessments, the effectiveness of the two bioflocculants for floc forming was also confirmed using a novel assessment of lens-free shadow imaging technique (LSIT), which was firstly applied for the rapid and quantitative assessment of microalgal flocculation.

• ALGAE
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• 제24권3호
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• pp.149-161
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• 2009

Characteristics of benthic microalgae and sediment properties were investigated for the intertidal flats of Kwangyang Bay, Korea. Sampling stations were selected every 100 m in the intertidal flats from land-side to open ocean at two different sampling sites. Samples were collected in June 2004, July, September, November, February and May 2005. Sediments properties were measured including temperature, water contents, sediment bulk density, nutrient concentrations in porewater. Chlorophyll a concentrations in surface sediment (0.5 cm) were measured and relationships between the chlorophyll a and various sediment properties were analyzed to identify major mechanisms regulating biomass of benthic microalgae in the intertidal flats using simple linear regression analysis. Sediment chlorophyll a concentrations were maximum during winter and minimum during warm seasons ranging from 4.4 mg $m^{-2}\;to\;81.2\;mg\;m^{-2}$. No clear spatial variations were observed for the sediment chlorophyll a in the study sites. Results from regression analysis suggested that benthic microalgae biomass was affected by sediment temperature and nutrients especially ammonium and silicate. Grazing effect was estimated using chlorophyll: pheopigments ratio, indirect indicator of grazing activity, and the positive correlation of the ratio and chlorophyll a implied that microalgae biomass is affected by grazing of zoobenthos although direct measurement of grazing activity is required to determine the importance of top-down controls in the benthic microalgae dynamics.

• Fisheries and Aquatic Sciences
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• 제27권1호
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• pp.23-34
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• 2024

While scientific information on the spatial variation of soda lake Microalgae is important to limnological studies, little information was reported from the Ethiopian Rift Valley Lake, Lake Chitu. This study aimed to understand the spatial distribution of the dominant Microalgae taxa in Lake Chitu, Ethiopia. The collection of samples and in situ measurements of some physico-chemical parameters were recorded at three sites for one cycle in November 2021. Fourteen species or genera of Microalgae were identified. Among those, Bacillariophyta were the most important with regard to species abundance and the rarest in species richness. Cyanophyta were the second-most important group in terms of species richness and rarity. Comparatively, all microalgae taxa were rare at both the anthropogenic areas (AA) and the flooding area (FA), which could be mainly due to intensive human and animal intervention and associated with extreme turbidity. Among Cyanophyta, Chroococcus minutus, Microcystis aeruginosa, and Spirulina platensis/fusiformis were predominant at both AA and FA, revealing their adaptation to less clear water and pollution. But S. platensis/fusiformis attained the highest abundance at the FA, indicating their preference for water in a highly nutrient-enriched area. We concluded that the spatial variation of microalgae diversity in relation to water quality parameters has implications for the importance of microalgae as a baseline indicator of water quality assessment tools in lakes.

• 상하수도학회지
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• 제38권2호
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• pp.109-117
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• 2024

In this study, various pre-treatment methods were evaluated for microalgae separation. These methods aimed to facilitate safe, rapid, and cost-effective online imaging for real-time observation and cell counting. As pre-treatment techniques, heating, chemical hydrolysis, heating combined with chemical hydrolysis, and sonication were employed. The effectiveness of these methods was evaluated in the context of online imaging quality through experimentation on cultivated microalgae (Chlorella vulgaris and Scenedesmus quadricauda). The chemical treatment method was found to be inappropriate for improving image acquisition. The heating pre-treatment method exhibited a drawback of prolonged cell dispersion time. Additionally, the heating combined with chemical hydrolysis method was confirmed to have the lowest dispersion effect for Chlorella vulgaris. Conversely, ultrasonication emerged as a promising technique for microalgae separation in terms of repeatability and reproducibility. This study suggests the potential for selecting optimal pre-treatment methods to effectively operate real-time online monitoring devices, paving the way for future research and applications in microalgae cultivation and imaging.

• 한국항공운항학회지
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• 제32권2호
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• pp.151-158
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• 2024

Microalgae are aquatic microorganisms capable of photosynthetic growth using water, carbon dioxide and sunlight, and can replace petroleum for transportation. It is receiving great attention as a potential next-generation biological resource. The microalgae biodiesel production process is largely based on the development of highly efficient strains and mass production. It consists of cultivation, harvesting, oil extraction, fuel conversion and by-product utilization. Currently, microalgae diesel is 3-5 times more expensive than petroleum diesel. However, with the optimization of each element technology and the development of integrated systems, not only biofuels, but also industrial materials, wastewater treatment, and greenhouse gases As application expands to various fields such as abatement, the timing of commercialization may be brought forward. Oil prices have recently fallen due to the influence of sail gas. Although there has been a significant drop, global warming is an urgent challenge for current and future generations. In particular, Korea, which does not have oil resources, We must always prepare for political environmental changes, high oil prices, and energy crises. In this paper, the need for eco-friendly biofuel for carbon dioxide conversion. In addition to research trends, domestic and international research trends, and economic prospects, the concept of microalgae and the element technologies of the biodiesel production process are briefly discussed introduced.

• 대한환경공학회지
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• 제30권1호
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• pp.85-89
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• 2008

정수 처리공정의 응집 침전공정에서 무기고분자응집제를 이용한 미세조류의 제거 가능성을 파악하기 위해서 응집제의 종류(Alum, PAC)와 응집영향인자(알칼리도, 응집제 주입량, 침전시간)에 따른 미세조류의 제거율과 미세조류의 크기(micro-, nano-, picoplankton)별 제거율과 주입된 응집제가 미세조류의 제거에 미치는 기여율을 평가하였다. 알칼리도의 주입량에 따른 조류의 제거율은 Alum의 경우 알칼리도가 25 mg/L의 조건에서 87.2%, PAC의 경우 알칼리도가 30 mg/L의 조건에서 90.1%로 가장 높은 제거율을 나타내었다. 조류의 제거율이 가장 높은 응집제 주입량은 Alum의 경우 40 mg/L로 제거율이 88.1%이었고, PAC의 경우는 주입량이 50 mg/L에서 제거율이 89.0%로 가장 높은 제거율을 나타내었다. 그리고 조류의 제거에는 PAC보다는 Alum이 다소 유리하다는 것을 알 수 있었다. 응집제가 주입되었을 경우 주입되지 않은 조건에 비해서 조류의 제거율이 약 2배 정도 증가하는 것을 알 수 있었다. 최적조건 하에서 조류의 제거율은 nanoplankton > microplankton > picoplankton의 순으로 나타났으며, 특히 picoplankton의 제거율은 약 30% 미만으로 제거율이 매우 낮은 것을 알 수 있었다.