• Journal of Korean Society of Water and Wastewater
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• v.26 no.2
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• pp.295-302
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• 2012

The coagulation of combined sewer overflows ($CSO_{s}$) was investigated by jar-testing with several commercial coagulants. $CSO_{s}$ sample showed different characteristics of coagulation from secondary wastewater with three common coagulants, aluminum sulfate, ferric chloride and polyaluminum chloride (PACl). Jar-tests showed that relatively wide range of optimal SS and T-P removal yielded with alum and ferric chloride compared with cationic polymers, though efficient SS and T-P removal can be achieved with all three coagulants. The decrease of pH was caused by the increase in dosage of aluminum sulfate, ferric chloride and PACl as coagulants. The pH was changed from 7.0 to 4.7 with the dosages of ferric chloride 25 mL/L. Aluminum sulfate revealed pH of 5.0 and PACl was highest pH of 5.4 after dosing of coagulants. The optimal pH to treat $CSO_{s}$ with aluminum sulfate were 6-6.5; with PACl 6-7, and with ferric chloride higher than 7.

• The Korean Journal of Food And Nutrition
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• v.33 no.5
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• pp.576-583
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• 2020

The purpose of this study was to compare the quality characteristics of silken tofu products from the commercial market in Korea. Seven types of commercial silken tofu were sampled and their physicochemical properties, including soluble solid contents, salinity, pH, total acidity, moisture contents (total solid contents), crude protein and fat contents were evaluated. The TPA results suggest that the texture of silken tofu was very different from one another according to the type of and the amount of coagulant. The commercial silken tofu showed a range of pH 5.53~6.48, total acidity of 0.12~0.32%, soluble solid contents of 2.62~5.07 °Brix, salinity of 2.28~4.30%, and moisture contents of 87.10~92.24%, respectively. In terms of the coagulant of tofu, besides the GDL (glucono-δ- lactone), other coagulants such as MgCl₂ for making 'silken tofu' in the Korean tofu market. The quality characteristics differed depending on the constituents of sample and the coagulants of tofu used. These results are expected to be useful in identifying new trends in the domestic silken tofu industry.

• Journal of Environmental Health Sciences
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• v.19 no.3
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• pp.29-35
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• 1993

This study was performed to obtain optimal conditions for reduction of color in dye wastewaters using coagulation-sedimentation processes with redox reactions. The reduction of color as well as organic matters variation was observed after coagulation-sedimentation processes using FeSO$_4$ $\cdot$ 7H$_2$O and NaOCl. Coagulation-redox reaction was done with the dose of Coagulant and oxidant at various pH values. Redox reaction was done through jar-mixing and aeration. The results of study were as follows: 1. In the coagulation-sedimentation processes using FeSO$_4$ $\cdot$ 7H$_2$O, color reduction was heigher at pH 3. With variance of dosage of FeSO$_4$ $\cdot$ 7H$_2$O, color reduction was higher at 250 mg/l. When coagulation-sedimentation using FeSO$_4$ $\cdot$ 7H$_2$O 250 mg/l was added at pH 3, the reduction of color, COD$_{Mn}$, and COD$_{Cr}$ showed 47.6%, 21.3% and 22.1%, respectively. 2. When NaOCI was added at level of 100 ppm in raw wastewater at pH 3, the reduction of color, COD$_{Mn}$, and COD$_{Cr}$ showed 30.2%, 5.5% and 6.2%, respectively. 3. After coagulation-sedimentation processes by addition of FeSO$_4$ $\cdot$ 7H$_2$O, when NaOCl was added at level of 250 mg/l in supernant, color reduction was 47.8% in aeration and 37.5% in jar-mixing. 4. Color reduction by aeration was higher than that by jar-mixing.

• Environmental Engineering Research
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• v.20 no.3
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• pp.285-289
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• 2015

Complicated and expensive seawater desalination technology is a big challenge in boron removal process. Conventional seawater desalination process of coagulation utilized for pre-treatment is difficult to remove boron. Boron can be removed more effectively in Reverse Osmosis (RO) process than any other processes. In this study, a coagulant with the name Mineral Cluster was examined its boron removal ability. Boron removal efficiency of Mineral Cluster depended on pH value and Mineral Cluster dosage. Desalination process combines the pre-treatment process with Mineral cluster diluted at the ratio of 1:2500 and the RO membrane process. The original sea water could be desalinated to drinking water quality, 1 mg/L, without any pH adjustments. Therefore, if the Mineral cluster is added without any other chemicals for adjusting pH, the desalination process would be much safer, efficient and economical.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.5
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• pp.323-334
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• 2021

Pilot-scale coagulation and sedimentation processes were operated to investigate the T-P (Total phosphorus) removal efficiency. A multiple regression model was also derived to predict the water quality improvement effect with river water characteristics. The inflow rates for the pilot-scale facility were 157-576 m³/day, and the coagulant doses were in the range of 13.7-58.5 mg/L (average 38.9 mg/L) for PAC (Poly alum chloride) and 16.5-62.1 mg/L (average 36.0 mg/L) for alum. The results found that the influent BOD (Biochemical oxygen demand) and T-P concentrations were 4.9 mg/L and 0.115 mg/L, and the removal efficiencies were 52.7% and 59.4%, respectively. T-P removal efficiencies on wet weather days were higher by 10% than dry weather days because influent solids influenced T-P's coagulation process. The pH of river water was 6.9-7.8, and the average pH was 7.3. Although the pH variation was not significant, the trend showed that the treatment efficiency of T-P and PO₄-P removal increased. Thus, the pH range considered in this study seems to be appropriate for the coagulation process, which is essential for phosphorous removal. The T-P removal efficiencies were 19.6-93.3% (average 59.2%) for PAC and 16.4-98.5%(average 55.9%) for alum; thus, both coagulants showed similar results. Furthermore, the average coagulant doses were similar at 42.4 mg/L for PAC and 41.3 mg/L for alum. When the T-P concentration of the effluent was compared by the [Al]/[P] ratio, the phosphorus concentration of the treated water decreased with an increasing [Al]/[P] ratio, and the lowest T-P concentration range appeared at the [Al]/[P] ratio of 10-30. A seasonal multiple regression analysis equations were derived from the relationships between 10 independent and dependent variables (T-P concentration of effluent). This study could help lake water quality maintenance, reduce eutrophication, and improve direction settings for urban planning, especially plans related to developing waterfront cities.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.2
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• pp.66-73
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• 1999

This study was carried out to derive the removal characteristics of target materials(DOC and turbidity) during the coagulation process after the injection of coagulants(PACl and FeCl3). Used apparatus were a jar test and a pilot plant. A great portion of DOC among the total removed DOC was achieved at the slow mixing process among the coagulation process. The ranges of removed DOC and optimum pH for each coagulant were 0.45~1.47mg/l and 6.0~6.5 by PACl, and 0.97~2.61mg/l. and 5.0~5.5 by FeCl3, respectively. Both of coagulants showed little increase of DOC removal above coagulant dosage 20mg/l Molecular weight distribution(MWD) of removed DOC was measured by get filtration(GF) technique. The MWD variation by gel filtrationin(GF) for removed DOC in the coagulation process were as follows; for raw water, the percentages of each MWD for total area were < MW 6,500 25.5%, MW 6,500~66,000 67.1%, and > MW 66,000 7.4%. For the same coagulant dosage(12mg/l), the percentages of each MWD for total area by PACl were < MW 6,500 20.5%, MW 6,500~66,000 48.7%, and > MW 66,000 9.1%, and those of FeCl3 were MW 66,000 18.2%. For each coagulant, the removal percentage of MW 6,500~66,000 occurred a little, but at a part of

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.6
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• pp.489-495
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• 2006

In recent years, there has been an interest to use Moringa oleifera as the natural coagulant due to cost, associated health and environmental concerns of synthetic organic polymers and inorganic chemicals. However, it is known that M. oleifera as the natural coagulant is highly biodegradable and has a very short shelf life. This research was carried out to investigate the effects of storage temperature, packaging methods, and freeze-drying on the preservation of M. oleifera seeds powders. Non freeze-dried M. oleifera was prepared into different packaging namely open container, closed container and vacuum packing, whilst, freeze-dried M. oleifera was stored in closed container and vacuum packing. Each of the packaging was stored at room temperature ($30\;to\;32^{\circ}C$) and refrigerator ($4^{\circ}C$). The turbidity removal efficiencies of stored M. oleifera were examined using jar test at monthly interval for 12 months. The results indicated that non freeze-dried M. oleifera kept in the refrigerator ($4^{\circ}C$) would preserve its coagulation efficiency. In addition, closed container and vacuum packing were found to be more appropriate for the preservation of non freeze-dried M. oleifera, compared to open container. Freeze-dried M. oleifera retained its high coagulation efficiency regardless the storage temperature and packaging method for up to 11 months. Besides, higher increment in zeta potential values for water coagulated with freeze-dried M. oleifera indicated the higher frequency of charge neutralization and better coagulation efficiency of freeze-dried M. oleifera, compared to non freeze-dried seeds. As a coagulant, M. oleifera did not affect the pH of the water after treatment.

• Journal of environmental and Sanitary engineering
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• v.12 no.3
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• pp.127-130
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• 1997

The removal of algae was conducted by loess, aluminum sulfate and PAC on a laboratory scale. The loess was consists of organic matter 1.4%, T-N $289{\mu}g/g$, T-P $17{\mu}g/g$, $Al841.2{\mu} g/g$, Fe $592.7{\mu}g/g$, Ca $10.6{\mu}g/g$, Mg $85.5{\mu}g/g$ and Mn $6.6{\mu}g/g$. Test water was dominated by Microcystis aeruginosa. When test water was mixed with 0.01, 0.05. and 0.1 g/$\ell$ of the loess in 5 minutes, after settled in 1 hour, the removal of chl-a was 2, 22, and 36% respectively. The removal of chl-a was 69%, 70% in pH 4.5 and 9.0 and above 92% between pH 5.0 and 8.0 after the $2mg/{\ell}$ of aluminum sulfate was added. When the $2mg/{\ell}$ of PAC and $0.05g/{\ell}$ of loess were added to test water together, the removal of chl-a was 95-99% in pH 4.0-8.0, 60% in pH 9.0, and 18% in pH 10.0. The removal of chl-a was higher when loess, aluminum sulfate and PAC was used together than used alone.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.9
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• pp.590-596
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• 2012

Enhanced coagulation is best available technologies to treat NOM in water to produce clean drinking water. In this research, the comparison experiments between conventional coagulation (CC) and enhanced coagulation (EC) using 4 type coagulants i.e., ferric chloride, aluminium sulphate (alum), poly aluminium sulphate organic magnesium (PSOM) and poly aluminium chloride (PACl) were performed in terms of surrogate parameters such as dissolved organic carbon (DOC), trihalomethane formation potential (THMFP), haloacetic acid formation potential (HAAFP) and zeta potential variation in order to find out the most effective coagulant and conditions to fit Nakdong River water. When applied to EC process, the turbidity removal efficiency did not increased gradually compared to the CC process when adding coagulants. Furthermore, the removal efficiency of turbidity became decreased much more as coagulants were added increasingly whereas the removal efficiency of DOC, THMFP and HAAFP became increased by 13~18%, 9~18% and 9~18% respectively compared to the CC process. The characteristics of turbidity removal showed relatively high removal efficiency considering the pH variation in entire pH range when using $FeCl_3$ and PACl. Additionally, in case of alum and PSOM steady removal efficiency was shown between pH 5 and pH 8. In terms of DOC surrogate the coagulants including 4 type coagulants indicated high removal efficiency between pH 5 and pH 7. The removal efficiency of dissolved organic matter (DOM) in EC between less than 1 kDa and more than 10 kDa augmented by 11~21% and 16% respectively compared to the CC process. The removal efficiency of hydrophobic and hydrophilic organic matter proved to be increased by 27~38% and 11~15% respectively. In conclusion, the most effective coagulant relating to EC for Nakdong River water was proved to be $FeCl_3$ followed by PSOM, PAC and alum in order.

• Food Science and Preservation
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• v.20 no.5
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• pp.636-642
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• 2013

Quality and sensory characteristics of tofu prepared with concentrated to 8 $^{\circ}Brix$ deep ground sea-like water (SW) were investigated to check the availability for coagulants. The tofu was coagulated with three kinds of commercially coagulant, such as $MgCl_2$, $CaSO_4$ and glucono-${\delta}$-lactone. Different amounts of SW and soybean milk were added: SW-20 g/L, SW-25 g/L and SW-30 g/L. The moisture content and pH were significantly lower in which preparation with glucono-${\delta}$-lactone coagulated tofu, and others has not significantly difference each other. The mineral contents in the coagulant influenced the mineral content of the tofu, which contained larger quantities of major minerals. However, the mineral content of the tofu was not affected of the mineral concentration in the coagulant. The L and b values of the tofu prepared with SW were not significantly different. The hardness of the tofu prepared with the commercial coagulants was significantly lower than that of the tofu produced with the SW. The sensory property was lower when the hardness was lower and higher. In conclusion, the quality characteristics of SW-prepared tofu were not significantly different from those of the tofu prepared with the commercial coagulants, but the texture and the taste of the SW-prepared tofu were excellent.