• Journal of Korean Society on Water Environment
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• v.24 no.1
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• pp.19-29
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• 2008

Hot air sparging is a groundwater remediation technique, in which organic contaminants volatilized into hot air from the saturated to vadose zone. In the laboratory diesel (10,000 mg TPH/kg) was spiked in contaminated saturated aquifer soil. The hot air ($34.9{\pm}2.7^{\circ}C$) was injected in intermittent (Q=1,500 mL/min, 10 minute injection and 10 minute idle) modes. We performed microcosm tests using the groundwater samples to assess TPH reductive remediation activity. For Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis of eubacterial communities in sludge of wastewater treatment plants and soil of experiment site, the 16S rDNA was amplified by Polymerase Chain Reaction (PCR) from the sludge and the soil. The obtained 16S rDNA fragments were digested with Msp I and separated by electrophoresis gel. We found various sequence types for hot air sparging experiment with sludge soil samples that were closely related to Bacillus (149 bp, Firmicutes), Methlobacterium (149 bp, Euryarchaeotes), Pseudomonas (492 bp, ${\gamma}$-Proteobacteria), etc., in the clone library. In this study we find that TPH-water was reduced to 78.9% of the initial value in this experiment aquifer. The results of the present study suggests that T-RFLP method may be applied as a useful tool for the monitoring in the TPH contaminated soil fate of microorganisms in natural microbial community.

• Journal of Korean Society of Water and Wastewater
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• v.38 no.4
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• pp.233-242
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• 2024

This study evaluates the potential of various coagulants to enhance the efficiency of total phosphorus removal facilities in a sewage treatment plant. After analyzing the existing water quality conditions of the sewage treatment plant, the coagulant of poly aluminium chloride was experimentally applied to measure its effectiveness. In this process, the use of poly aluminium chloride and polymers in various ratios was explored to identify the optimal combination of coagulants. The experimental results showed that the a coagulants combination demonstrated higher treatment efficiency compared to exclusive use of large amounts of poly aluminium chloride methods. Particularly, the appropriate combination of poly aluminium chloride and polymers played a significant role. The optimal coagulant combination derived from the experiments was applied in a micro flotation method of real sewage treatment plant to evaluate its effectiveness. This study presents a new methodology that can contribute to enhancing the efficiency of sewage treatment processes and reducing environmental pollution. This research is expected to make an important contribution to improving to phosphorus remove efficiency of similar wastewater treatment plant and reducing the ecological impact from using coagulants in the future.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.2
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• pp.203-209
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• 2015

The purpose of this study is to estimate the applicability of a stable anaerobic digester using a separator membrane to the preprocessing thickening process. The results of the experiments showed about a 47.16% weight loss rate for the sludge under anaerobic condition, and about 41.17% under intermittent aeration condition. The concentrations of rejection water were $SCOD_{Cr}$ 25 mg/L, T-N 16.6 mg/L, and T-P 1.4 mg/L on the average under the intermittent aeration condition, which were lower than the concentrations of rejection water under an anaerobic condition. As for the factors affecting the reduction of the flux, correlation analyses of TTF, MLSS, $SCOD_{Cr}$, and $EPS_{Protein}$, $EPS_{Polysacchride}$ resulted in -0.97, -0.95, -0.84 and -0.86, -0.95, respectively, which showed that TTF had the highest correlation to the reduction of the flux. In addition, it was concluded that MLSS, $SCOD_{Cr}$ and $EPS_{Protein}$, $EPS_{Polysacchride}$ also have close correlations. The results are considered to show that, in the case of the process using a tubular membrane in the preprocessing process of an anaerobic digester, an intermittent aeration condition of the thickener considering the contamination of the membrane and load of rejection water is appropriate for the stable preprocessing process.

• Membrane and Water Treatment
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• v.9 no.5
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• pp.363-371
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• 2018

In this work, it was investigated the usability of artificial bee colony (ABC) and genetic algorithm (GA) in modeling adsorption of Co(II) onto drinking water treatment sludge (DWTS). DWTS, obtained as inevitable byproduct at the end of drinking water treatment stages, was used as an adsorbent without any physical or chemical pre-treatment in the adsorption experiments. Firstly, DWTS was characterized employing various analytical procedures such as elemental, FT-IR, SEM-EDS, XRD, XRF and TGA/DTA analysis. Then, adsorption experiments were carried out in a batch system and DWTS's Co(II) removal potential was modelled via ABC and GA methods considering the effects of certain experimental parameters (initial pH, contact time, initial Co(II) concentration, DWTS dosage) called as the input parameters. The accuracy of ABC and GA method was determined and these methods were applied to four different functions: quadratic, exponential, linear and power. Some statistical indices (sum square error, root mean square error, mean absolute error, average relative error, and determination coefficient) were used to evaluate the performance of these models. The ABC and GA method with quadratic forms obtained better prediction. As a result, it was shown ABC and GA can be used optimization of the regression function coefficients in modeling adsorption experiments.

• Journal of Korean Society on Water Environment
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• v.27 no.3
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• pp.286-292
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• 2011

Preparing for the Standards for Effluents which will be strengthen from 2012, many ways like remodellings and repairs of sewage treatment plant (STP) are considered. The treatment of the recycle water from the sludge treatment process contains high-strength organic compounds and nitrogen is considered as alternative. In the treatment of high-strength nitrogen, nitritation has more economic advantages than nitrification. In this study, lab-scale reactor was operated at the $35^{\circ}C$, $20^{\circ}C$ and $10^{\circ}C$ conditions using effluent of anaerobic digester to investigate the nitrogen removal by nitritation. Long-term stable nitritation was achieved at the $35^{\circ}C$, $20^{\circ}C$ but $10^{\circ}C$. In the stable nitritation states, nitrite conversion was higher at the high temperature of $35^{\circ}C$ than the room temperature of $20^{\circ}C$. Also shorter solid retention time (SRT) was needed to induce high nitrite conversion at the high temperature of $35^{\circ}C$. It was showed that temperature and SRT are important factors to induce nitritation.

• Journal of environmental and Sanitary engineering
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• v.22 no.4
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• pp.119-130
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• 2007

Sea food wastewater including high concentration of organics and nutrients is hard to treat stably by established traditional activated sludge process. This research is aimed to obey more and more of strengthened the law and to secure stable effluents by using advanced treatment process applied membrane filter in aeration tank for treatment of wastewater from marine products. It must maintain pH of influent over 6.0 to keep up stably biological sludge of advanced treatment process. At 38hr of HRT, removal rates of TBOD and TCOD were 99.9% and 99.4% respectively and TSS also removed with high efficiency. Most organics in the effluent was constituted with soluble type materials, it caused that membrane filter installed aeration tank should remove minute suspended particles. The reactor was operated well to get stable treatment results for operation period, in spite of high loading of organics like that $0.67{\sim}1.67\;kgTBOD/m^3/day$ of organics loading and $0.10{\sim}0.21\;kgBOD_5/kgMLSS/day$ of F/M ratio. At $36{\sim}48hr$ of HRT, removal rates of T-N and T-P were $89.7{\sim}90.7%\;and\;91.5{\sim}96.0%$ respectively. It means this treatment process also work to remove nutrients of high concentration. Upon investigation of advanced treatment's operation factors, optimum SRT was about 30days and average SNR that showed tendency to increase according to increase water temperature was calculated 0.014 gN/g MLVSS/d. SDNR was risen in conformity to increase F/M ratio of Non-aeration tank and investigated as $0.038{\sim}0.051\;gN/gMLVSS/d$.

• Journal of Environmental Health Sciences
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• v.32 no.4 s.91
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• pp.336-341
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• 2006

The biological wastewater treatment system is known to have an important role in reducing the quantify of enteric virus in water environments. To clarify the roles of activated sludge microbes in decreasing the virus infectivity, the behavior of the virus in bacteria, protozoa, and metazoa was examined by pure or mixed culture system using poliovirus type 1(Lsc, 2ab strain). In the bacterial culture systems, the virus infectivity in the liquid phase decreased by a reversible adsorption of the virus to the bacteria or bacterial flocs. On the other hand, in the protozoa and the metazoa culture systems using T. pyriformis and P. erythrophthalma, respectively, with a variety of bacterial strains as prey, the main virus decrease mechanism of reversible adsorption in early stage was changed to irreversible predation, which was not eluted in this study. The virus decrease was more effective in the P. erythrophthalma culture system, which had high predation and floc forming abilities. However, in the mixed culture system of Z. ramigera and P. erythrophthalma, the more rapid reversible adsorption of virus to Z. ramigera flocs preceded the irreversible predation of P. erythrophthalma.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.71-76
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• 1987

The purpose of this study was to know reduction of organic matter, degree of humification and composting period by corp. posting of night soil sludge. Laboratory reactor was used for this study. Samples being used in this experimentation was sludge of night soil treatment plant. The degree of composting was investigated by changing moisture content. The laboratory study indicated that the degree of humification was about 175, C/N ratio was about 11~13, composting period was about 10 days and COD reduction was 37mg/l/day in case of 60% moisture content.

• Journal of Applied Biological Chemistry
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• v.52 no.2
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• pp.88-91
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• 2009

• Journal of Korean Society of Water and Wastewater
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• v.35 no.1
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• pp.1-14
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• 2021

Eutrophication and algal blooms can lead to increase of taste and odor compounds and health problems by cyanobacterial toxins. To cope with these eco-social issues, Ministry of Environment in Korea has been reinforcing the effluent standards of wastewater treatment facilities. As a result, various advanced phosphorus removal processes have been adopted in each wastewater treatment plant nation-widely. However, a lot of existing advanced wastewater treatment processes have been facing the problems of expensive cost in operation and excessive sludge production caused by high dosage of coagulant. In this study, the sedimentation and dissolved air flotation (SeDAF) process integrated with sedimentation and flotation has been developed for enhanced phosphorus removal in wastewater treatment facilities. Design and operating parameters of the SeDAF process with the capacity of 100 ㎥/d were determined, and a demonstration plant has been installed and operated at I wastewater treatment facility (located in Gyeonggi-do) for the verification of field applicability. Several empirical evaluations for the SeDAF process were performed at demonstration-plant scale, and the results showed clearly that T-P and turbidity values of treated water were to satisfy the highest effluent standards below 0.2 mg/L and 2.0 NTU stably for all of operation cases.