• KSBB Journal
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• v.27 no.2
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• pp.103-108
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• 2012

The harvesting of microalgae is a critical step that precedes biodiesel conversion. The most widely used harvesting technology is flocculation and floatation. In this study, the efficiency of the flocculants aluminum sulfate and poly aluminum chloride were evaluated for harvesting the alga Dunaliella tertiolecta in conjunction with dissolved air floatation. Using the jar test the optimum concentration range for aluminum sulfate was 1.0~1.5 g/L and for poly aluminium chloride, 1.5~2.0 g/L. The degree of coagulation was visualized by microscopy. Further analysis in combination with dissolved air floatation showed that the optimal concentration for aluminum sulfate was 1.1 g/L and for poly aluminum chloride, 1.6 g/L.

• Journal of Veterinary Clinics
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• v.4 no.2
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• pp.491-498
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• 1987

In an effort to compare parasite egg detection efficiencies, fecal samples from 231 dairy and Korean native cattle in the area of Hongsung - Gun, Kangwon-Do, were examined by the sedimentation and floatation methods. The results obtained were summarized as follows : 1. Detection rates of Fasciola hepatica were 27.2% by the sedimentation method and 61.6% by the floatation method, and those of Paramphistomum spp., were 48.9% and 66.2% respectively. 2. In the Fasciola hepatica, the numbers of cattle contained over a hundred eggs were one by the sedimentation method, but ten by the floatation method. For the Paramphistomum spp., the numbers of cattle contained over a hundred eggs were six by the sedimentation method, but thirty three by the floatation method. Thus, the number of the parasite eggs detected were greater when examined by the floatation method than by the sedimentation method. 3. The numbers of cattle from which eggs were detected only by the sedimentation methods were three and four for Fasciola hepatica and Paramphistomum spp., respectively, while those by the floatation method only were 55 and 44. respectively. 4. Trematodes, nematodes. protozoa and cestodes were floatated by the floatation method using zinc sulfate solution (specific gravity 1.27).

• Parasites, Hosts and Diseases
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• v.47 no.4
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• pp.353-357
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• 2009

Cryptosporidium can cause gastrointestinal diseases worldwide, consequently posing public health problems and economic burden. Effective techniques for detecting contaminated oocysts in water are important to prevent and control the contamination. Immunomagnetic separation (IMS) method has been widely employed recently due to its efficiency, but, it is costly. Sucrose floatation technique is generally used for separating organisms by using their different specific gravity. It is effective and cheap but time consuming as well as requiring highly skilled personnel. Water turbidity and parasite load in water sample are additional factors affecting to the recovery rate of those 2 methods. We compared the efficiency of IMS and sucrose floatation methods to recover the spiked Cryptosporidium oocysts in various turbidity water samples. Cryptosporidium oocysts concentration at 1, $10^1$, $10^2$, and $10^3$ per $10{\mu}l$ were spiked into 3 sets of 10 ml-water turbidity (5, 50, and 500 NTU). The recovery rate of the 2 methods was not different. Oocyst load at the concentration < $10^2$ per 10 ml yielded unreliable results. Water turbidity at 500 NTU decreased the recovery rate of both techniques. The combination of sucrose floatation and immunofluorescense assay techniques (SF-FA) showed higher recovery rate than IMS and immunofluorescense assay (IMS-FA). We used this SF-FA to detect Cryptosporidium and Giardia from the river water samples and found 9 and 19 out of 30 (30% and 63.3%) positive, respectively. Our results favored sucrose floatation technique enhanced with immunofluorescense assay for detecting contaminated protozoa in water samples in general laboratories and in the real practical setting.

• Resources Recycling
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• v.25 no.6
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• pp.98-104
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• 2016

The purpose of this study is to obtain an optimum condition of the concentrate by floatation using Australian low grade copper ore of suitable particle size by crushing, grinding and sizing. The effect of the dosage of collector, activator, depressant and change of acidity on the floatation was investigated. The floatation conditions comprising of pH 9.0 acidity, 500g/t $CuSO_4{\cdot}5H_2O$ activator, 500g/t K.E.X. collector, 1500g/t $Na_2SO_3$ depressant and 25wt.% plup density were optimized. Grade and recovery of copper in the concentrate obtained by froth floatation under optimum conditions were 4wt.% and 65wt.% respectively.

• Economic and Environmental Geology
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• v.19 no.2
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• pp.85-96
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• 1986

The Bupyeong Silver mine which is located approximately 35km west of Seoul is currently the leading silver producer in Korea. The deposits occur as stockwork deposits hosted in Jurassic pyroclastic rocks. Occurrences of ore deposits and mineral paragenesis suggest a division of mineralization into four stages: Stage I, deposition of iron oxide and base metal sulfides; Stage II, deposition of tin oxide and silverm inerals; stage III, deposition of native silver and other silver minerals; Stage IV, formation of pyrite bearing siderite veinlets, Silver minerals in ore are native silver, argentite, freibergite, pyrargyrite, canfieldite, polybasite, dyscrasite and Ag-Fe-S mineral. The most important silver mineral is native silver among them. Chemical composition of important silver minerals were determined by electron probe microanalyser. Assay, size and modal analyses for floatation products were carried out. In floatation products, relative proportion of native silver for total important silver minerals have following ranges: feed, 64.7 to 74.74 wt.%; A-cleaner concentrate, 80.58 to 98.79 wt.%; and final tailing, 28.12 to 72. 57 wt. %. Average degree of liberation for native silver in feed and A-cleaner concentrate are 60.49% and 77.57% respectively. Negative relationship can be recognized between native silver and argentite in their abundance and behavior in floatation precesses.

• KSBB Journal
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• v.16 no.3
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• pp.225-232
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• 2001

The hydrophobicity of the microbial cell surface is responsible for the various interactions between microorganisms and different surface, and results in the flocculation of microbial cells, their adhesion to liquid or solid materials, and the floatation of microorganisms at the air-water interface. Accordingly, cell surface hydrophobicity is important not only in medicine but in other areas of biotechnology. This article reviews the role of cell surface hydrophobicity and its applications.

• Journal of Soil and Groundwater Environment
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• v.20 no.5
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• pp.41-46
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• 2015

Three types of experiments, based on the physical properties of oily sludge landfilled soil, were conducted to recover total petroleum hydrocarbons (TPH) from the soil. These experiments included gravity separation, solvent extraction using water, and air floatation. The oil portion was not easily separated from the wet (raw) soil because water molecules aggregate the soil particles, despite the fact that the soil was sandy. However, the drying and grinding processes destroyed the aggregates, causing the TPH recovery to increase to approximately 60% when air floatation was used. The drying process decreased the specific gravity of the soil sample, thereby enhancing the overall recovery of TPH from the soil. Although thermal desorption and/or incineration are common choices for heavily dumped sites, physical separation can recover the oil portion instead of simply removing it.

• Journal of the Korean Professional Engineers Association
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• v.27 no.3
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• pp.83-90
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• 1994

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.479-489
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• 2014

Membrane backwashing waste shows seasonally different characteristics and it has bad settleability differently from general backwashing waste in water treatment plant. When chemicals was injected to membrane backwashing waste, the settleability was better than chemicals was not injected. However, when settled lower sludge was not discharged, flowing sludge continuously was concentrated over a certain surface and floatation penomena occurred according to flowing velocity. When the lower sludge was discharged continuously in the thickener to prevent floatation penomena of turbidity materials, the depth of sludge surface was the least and the settleability increased.

• Journal of Environmental Health Sciences
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• v.24 no.2
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• pp.9-19
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• 1998

Laboratory experiments were carried out to investigate the performance of anaerobic sequencing batch reactor(ASBR) for digestion of a municipal sludge. Each cycle of the ASBR comprised feeding, two-or three-day reaction, one-day thickening, and withdrawal. The reactors were operated at an HRT of 10days and 5days with an equivalent organic loading rate of 0.8-1.54 gVS/l/d, 1.81-3.56 gVS/l/d at 35$\circ$C, respectively. Solids accumulation was remarkable in the ASBR during start-up period, and directly affected by settleable solids in the feed sludge. Floatation thickening occured in the ASBRs, and Solids profiles at the end of thickening step dramatically changed at solid-liquid interface. Slight difference in solids concentrations was observed within thickened sludge bed. Efficiencies through floatation thickening were comparable to that of additional thickening of the completely mixed control reactor. Average solids concentrations in the ASBRs were 2.2-2.6 times higher than that in the control throughout the total operation period. The dehydrogenase activity had a strong correlation with the solids concentration. Organics removals based on clarified effluent of the ASBRs were consistently above 86%. Remarkable increase in equivalent gas production of 27-52% was observed at the ASBRs compared with the control though the control and ASBRs showed similiar effluent quality. Thus, digestion of a municipal sludge was possible using the ASBR in spite of high concentration of solids in the sludge.