• Microbiology and Biotechnology Letters
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• v.50 no.1
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• pp.110-121
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• 2022

The effluents from industries processing vegetable oils are extremely rich in sulfates, often exceeding the maximum concentration allowed to release them to the environment. Biological sulfate reduction is a promising alternative for the removal of sulfates in this type of wastewater, which has other particularities such as an acidic pH. The ability to reduce sulfates has been widely described for a particular bacterial group (SRB: sulfate-reducing bacteria), although the reports describing its application for the treatment of sulfate-rich industrial wastewaters are scarce. In this work, we describe the use of a natural SRB-based consortium able to remove above 30% of sulfates in the wastewater from one of the largest edible oil industries in Peru. Metataxonomic analysis was used to analyse the interdependencies established between SRB and the native microbiota present in the wastewater samples, and the performance of the consortium was quantified for different sulfate concentrations in laboratory-scale reactors. Our results pave the way towards the use of this consortium as a low-cost, sustainable alternative for the treatment of larger volumes of wastewater coming from this type of industries.

• KSBB Journal
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• v.19 no.3
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• pp.236-240
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• 2004

Korean wastewaters have higher nitrogen concentrations than typical wastewaters of other countries. Most treatment processes such as activated sludge processes will need to supplement extra carbon sources for a complete removal of remaining nitrogen after the initial wastewater treatment, Because of these difficult matters, we have searched wastewater treatment methods that require no additional carbon sources. Wastewater treatment by microalgae in photobioreactors, using a green eukaryotic microalgae, Chlorella kessleri, showed a promising results and thus was selected to study further. This system is not intended to replace the conventional system but is to assist the existing biological treatment systems as a supplemental nitrogen removal process. Thus the secondary treated livestock wastewater was tested. Column type photobioreactors developed in our laboratory were used. When aerated with 5% CO$_2$ balanced with air at 1 vvm and illuminated at 100 ${\mu}$mol/㎡/s under 25$^{\circ}C$ and PH 7-8 by CO$_2$ buffering effect, the maximum nitrogen removal rate was 2.6 mg/L/hr. The results confirmed a possibility of microalgal wastewater treatment system as a secondary system to remove extra nitrogen sources. Based on these experimental results, the size of the optimal microalgal wastewater system was calculated. For the wastewater whose initial nitrogen concentration of 150 mg/L, the optimal batch system was found to be a 2 stage system with a combined retention time of 4.6 day. From the continuous experiments, nitrogen removal rates were examined under different dilution rates and 2 stage system was also found to be the optimal system. The combined retention time for the continuous system was 3.5 days. It is expected that conventional biological wastewater treatment systems followed by microalgal systems would reliably decrease the nitrogen concentration below the government criteria even for the livestock wastewater with low C/N ratio.

• Environmental Engineering Research
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• v.20 no.2
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• pp.199-204
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• 2015

In this study, a novel phosphorus removal filter made of brass scrubber with higher porosity of over 96% was fabricated and evaluated. The brass scrubber was surface-modified to form copper hydroxide on the surface of the brass, which could be a phosphate removal filter for advanced wastewater treatment because the phosphates could be removed by the ion exchange with hydroxyl ions of copper hydroxide. The evaluation of phosphate removal was performed under the conditions of the batch type in wastewater and continuous type through filters. Filter recycling was also evaluated with retreatment of the surface modification process. The phosphate was rapidly removed within a very shorter contact time by the surface-modified brass scrubber filter, and the phosphate mass of 1.57 mg was removed per gram of the filter. The possibility of this surface-modified brass scrubber filter for phosphorus removal was shown without undesirable sludge production of existing chemical phosphorus removal techniques, and we feel that it would be very meaningful as a new wastewater treatment.

• Membrane and Water Treatment
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• v.1 no.1
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• pp.83-92
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• 2010

To improve the antifouling characteristics of polypropylene hollow fiber microporous membranes in a submerged membrane-bioreactor for wastewater treatment, the surface-modification was conducted by Ar plasma treatment. Surface hydrophilicity was assessed by water contact angle measurements. The advancing and receding water contact angles reduced after the surface modification, and hysteresis between the advancing and receding water contact angles was enlarged after Ar plasma treatment due to the increased surface roughness after surface plasma treatment. After continuous operation in a submerged membrane-bioreactor for about 55 h, the flux recovery after water cleaning and the flux ratio after fouling were improved by 20.0 and 143.0%, while the reduction of flux was reduced by 28.6% for the surface modified membrane after 1 min Ar plasma treatment, compared to those of the unmodified membrane. Morphological observations showed that the mean membrane pore size after Ar plasma treatment reduced as a result of the deposition of the etched species; after it was used in the submerged membrane-bioreactor, the further decline of the mean membrane pore size was caused by the deposition of foulants. X-ray photoelectron spectroscopy and infrared spectroscopy confirmed that proteins and polysaccharide-like substances were the main foulants in the precipitate.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.89-95
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• 1997

The current processer of the textile wastewater treatment are mostly consisted of a combination of a physico-chemical and a biological treatment. The overall efficiency of these processes is, however, assessed to be fairly low. It is even worse during the summer season when temperature of the wastewater rises above 40$\circ $C. Therefore, a feasible process of the textile wastewater treatment which can work efficiently at higher temperatures was investigated in this work. We used a bench scale reactor consisted of one 4 liter anaerobic and one 8 liter aerobic tank, and the thermophilic symbiotic PVA degraders, Pasteruella hemolytica KMG1 and Pseudomonas sp. KMG6 that had been isolated in our laboratory. In the preliminary flask experiments, we observed that the thermophilic symbiotic PVA degraders could not grow in the wastewater substrate. Then, we isolated the mutant strains by acclimating the KMG1and KMG6 strains to the wastewater medium. The mutant symbionts (KMG1-1 and KMG6-1) were isolated through 6 times successive transfers into the fresh wastewater medium after 5 days culture for each. The mutant strains obtained grew well in the mixed medium composed of 75% wastewater and 25% synthetic medium, and supplemented with 0.5% PVA as a sole carbon source. During the culture for 14 days at pH 7.0 and 40$\CIRC $C, the bacteria assimilated about 89% of the added PVA. The symbionts degraded equally well all the PVA substrates of different molecular weight (nd=500~30000). In contrast to the flask experiments, in the reactor system the mutant strains showed very low levels of the PVA and COD removal rates. However, the new reactor system with an additional aerobic tank attained 82% removal rate of COD, 94% of PVA degradation and 71% of color index under the conditions of 5% inoculm on the tank 2, incubation temperature of 40$\circ $C, dissolved oxygen level of 2~3 mg/l and retention time of 30 hours. This result ensures that the process described above could be an efficient and feasible treatment for the PVA contained textile wastewater at higher temperatures.

• Journal of Environmental Science International
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• v.13 no.3
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• pp.251-262
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• 2004

To identify the characteristics of wastewater flow generated in treatment basins of Seogwipo-city, we selected 3 stations representing the basin and performed 7 times of field survey including 5 times in dry periods and 2 times in wet periods from Feb. 25 to May 27, 2002 for the selected stations. From the analysis of flow data measured for more than 60 days in the interval of 5 minutes and concentration data obtained from laboratory analysis, we can draw several conclusions. First, in the analysis of diurnal variation of wastewater flow for land-use types, we could find the following results: in the residential area, it is observed that wastewater flow rates rise early in the morning for the office-going hour and fall gradually and rise again after the office-leaving hour, showing typical residential wastewater flow pattern, while for the residential and commercial area flow rates rise early in the morning at the office-going hour and move up and down repeatedly within wide range and last till the office-leaving hour, which can be resulted from wastewater that is generated by tourists activated after early in the afternoon, while for the touristy area flow rates rise early in the morning and fall gradually and rise again within wide range. Second, in the analysis of temporal variation of wastewater flow for monthly, it can be observed that in the residential area, in the residential and commercial areas the flow rate of May is higher than that of Feb., March, while for the touristy area flow rate is without monthly because it reflects the movement of population, Third, in wet periods concentration of water-quality item such as SS, BOD, and COD_{cr}$ is high in the beginning of rainfall by first flush, and falls down gradually to reach the steady state, which is the level of wastewater in dry periods after the cease of storm water due to diluting effect resulting from additional runoff water through storm sewers.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.901-908
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• 2002

The relationship between the layered structure of granules in UASB reactors and microbial resistance to toxicity was investigated using disintegrated granules. When no toxic materials were added to the media, the intact and disintegrated granules exhibited almost the same ability to decrease COD and to produce methane. However, when metal ions and organic toxic chemicals were added to a synthetic wastewater, he intact granules were found to be more resistant to toxicity than the disintegrated granules, as determined by the methane production. The difference in resistance between the intact and disintegrated granules was maximal, with toxicant concentrations ranging from 0.5 mM to 2 mM for trichloroethylene with toluene and 5 mM to 20 mM for metal ions (copper, nickel, zinc. chromium, and cadmium ions). The augmented COD removal rate by granulation compared to disintegrated granules was also measured in the treatment of synthetic and real wastewaters; synthetic wastewater, $-2.6\%$; municipal wastewater, $2.8\%$; swine wastewater, $6.4\%$; food wastewater, $25.0\%$; dye works wastewater, $42.9\%$; and landfill leachate, $61.8\%$. Continuous reactor operation also demonstrated that the granules in the UASB reactor were helpful in treating toxic wastewater, such as landfill leachate.

• Environmental Engineering Research
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• v.19 no.3
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• pp.283-287
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• 2014

Cultivation of microalgae using wastewater exhibits several advantages such as nutrient removal and the production of high valuable products such as lipid and pigments. With this study, two types of wastewater from instant noodle factory; mixed liquor suspended solids (MLSS) and effluents after sedimentation tank were investigated for green microalga Scenedesmus sp. cultivation under laboratory condition. Optimal wastewater dilution percentage was evaluated in 24 wells microplate. MLSS and effluent without dilution showed the highest specific growth rate (${\mu}$) of $1.63{\pm}0.11day^{-1}$ and $1.57{\pm}0.16day^{-1}$, respectively, in which they were significantly (p < 0.05) higher than Scenedesmus sp. grown in BG11 medium ($1.08{\pm}0.14day^{-1}$). Ten days experiment was also conducted using 2000 ml Duran bottle as culture vessel under continuous light at approximately 5000 lux intensity and continuous aeration. It was found that maximum biomass density of microalgae cultivated in MLSS and effluent were $344.16{\pm}105.60mg/L$ and $512.89{\pm}86.93mg/L$ respectively and there was no significant (p < 0.05) difference on growth to control (BG11 medium). Moreover, cultivation microalgae in wastewater could reduce COD in wastewater by 39.89%-73.37%. Therefore, cultivation of Scenedesmus sp. in wastewater from instant noodle factory can yield microalgae biomass production and wastewater reclamation using photobioreactor simultaneously.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.699-701
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• 2002

The current study demonstrates the ability of the marine cyanobacterium Oscillatoria willei BDU130511 to disinfect raw sewage. Within a holding time of 3 h under laboratory conditions, the organism drastically reduced in the total bacterial and coliform counts at various pH levels, in both unbuffered and buffered sewage, thereby suggesting a potential role for cyanobacteria in wastewater treatment.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2001.12a
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• pp.99-99
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• 2001