• Journal of Environmental Science International
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• v.24 no.12
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• pp.1551-1558
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• 2015

In Korea, many drinking water treatment plants (DWTPs) have introduced and are going to introduce biological activated carbon (BAC) process to treated dissolved organic matter (DOM) in water which are difficult to control by conventional water treatment processes. Even though more decade have passed since introduced BAC in Korea, most of BAC operating method was followed to the modified sand filter operating manuals. In case of BAC backwashing, many DWTPs set the periods of backwashing about 3~5 days. In this study, we have collected data to set the proper BAC backwashing periods from both pilot-plant and real DWTPs. We had measured heterotrophic plate count (HPC), turbidity, water temperature, dissolved organic carbon (DOC) and headloss from just after backwashing to the next backwashing time for two years. Considering water quality factors, the BAC run time from backwashing to the next backwashing could extend more 30 days without water quality deterioration if the head loss do not reach the limited level which depends on each BAC facilities' condition. It means the BAC treated water could be saved in the proportion of extended the backwashing period to the existing backwashing period.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.431-444
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• 2020

The relationship between dam construction and water quality has recently come to be considered an important issue. A dam is a physical factor which causes changes to the river system around it. Considering these points, this study was conducted to obtain basic data by analyzing the relationship between water level fluctuations and water quality parameters in the short-term. In terms of methodology, the new construction of the Yeongju Dam (M5) in 2016 was divided into Stage 1 as the lotic system and Stage 2 as the lentic system, with four years in each period, and the water level fluctuations and water quality were analyzed using official data. As a result of this study, M5, a stagnant area in which organic matter and nutrients accumulate, was found to be an important factor in water quality management. In addition, the water level changed rapidly (0.9±0.2 m → 10.9±7.1 m) as the river environment condition was converted from the lotic system to the lentic system. In addition, water quality parameters such as BOD, COD, TOC, and Chl-a significantly changed in the short-term. Further, since the transport of organic matter and nutrients occurred well in the lotic system, sedimentation was expected to be dominant in the lentic system. Therefore, it was determined that when the river flow is blocked, autochthonous organic matter is an important factor for long-term water quality management in the future. This process can increase the trophic state of the water body. As a result of this study, the TSI_KO value was converted from mesotrophic in Stage 1 to eutrophic in Stage 2. Eventually, short-term changes in the river environment will affect not only changes in water level but also changes in water quality. Thus, a comprehensive and strategic approach is needed for long-term water quality management in the future.

• Journal of Korean Society on Water Environment
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• v.37 no.6
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• pp.425-432
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• 2021

A tidal power plant (TPP) has been in operation since the end of 2011 to improve the water quality of Shihwa Coastal Reservoir (SCR). Tidal mixing rate increased 5.6 times after the TPP operation so that in this study, its effects on water quality was assessed through statistical analysis of long-term water quality monitoring data. It was found that the increased tidal mixing contributed to solving the hypoxia problem in the bottom water by preventing the summer stratification. The analysis also showed that the increased tidal mixing had different effects depending on the relative concentration difference for each water quality substances between the SCR and the outside of SCR. The average concentrations of some substances (chemical oxygen demand, total phosphorus, chlorophyll-a) with higher concentrations than the outside of SCR decreased due to the dilution effect, but the other substances (total nitrogen, dissolved inorganic nitrogen, dissolved inorganic phosphorus) with lower concentrations compared to the outside ones increased on the contrary. Factor analysis also showed a consistent result that the first factor accounting for the water quality was changed from the organic-related substances to the nutrient-related substances after the increased tidal mixing. These results imply that the focus of future water quality management needs shifting from the organic substances to the nutrients, particularly dissolved inorganic nutrients. Considering the effect of inflow seawater on the nutrients, the management area should be extended to cover not only SCR but also a certain area outside of SCR.

• Culinary science and hospitality research
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• v.24 no.3
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• pp.104-112
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• 2018

The purpose of this study was to examine the quality characteristics of white pan bread according to the different types of water (tap water (still water), purified water, still water, light water, classical water, and bold water). Pan breads were statistically analyzed using texture profile analysis, fermentation, texture, suitability, image analysis, color, moisture content, and statistical analysis. This result will contribute to the commercialization of pan bread using various kinds of water. Ultimately, we analyzed the quality characteristics of various kinds of water, depending on the carbonic acid content on the dough and the pan bread, and to derive the optimum kinds and ratios of the water to be applied to the pan bread. As a result of the study, the best findings were obtained with water containing carbonic acid content more than the classical water according to overall characteristics, durability (Width of Tail and Integral), foot efficiency, softness, volume and preference check. Therefore, when white pan bread is produced by using water containing a carbonic acid content (5~7.5 mg/L) or more of the classical water, it affects the quality characteristics and a good obtains positive response to from consumers. In this study, the quality characteristics of pan bread based different kinds of water which were not available in the past, and the quality characteristics of pan bread, which can be used as the basic data for future research, were well analyzed.

• Journal of Environmental Impact Assessment
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• v.18 no.2
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• pp.59-67
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• 2009

Water quality of the Lake Youngrang in the Sokcho City is eutrophic. Jangcheon is the largest inflow source to the lake. Major pollutant sources are stormwater runoff from resort areas and various land uses in the Jangcheon watershed. A storm sewer on the southern end of the lake is also an important pollution source. In this study, water quality modelling for Lake Youngrang was carried out considering the rainfall-runoff pollution loads from the watershed. The rainfall-runoff curves and the rainfall-runoff pollutant load curves were derived from the rainfall-runoff survey data during the recent 4 years. The rainfall-runoff pollution loads and flow from the Jangcheon watershed and the storm sewer were estimated using the two kinds of curves, and they were used as the flow and the boundary data of the WASP model. With the measured water quality data of the year 2005 and 2006, WASP model was calibrated. Non-point pollution control measures such as wet pond and infiltration trench were considered as the alternative for water quality management of the lake. The predicted water quality were compared with those under the present condition, and the improvement effect of the lake water quality were analyzed.

• Journal of Environmental Science International
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• v.24 no.9
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• pp.1123-1129
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• 2015

This research was performed by means of several different virgin granular activated carbons (GAC) made of each coal, coconut and wood, and the GACs were investigated for an adsorption performance of iodine-131 in a continuous adsorption column. Breakthrough behavior was investigated that the breakthrough points of the virgin two coals-, coconut- and wood-based GACs were observed as bed volume (BV) 7080, BV 5640, BV 5064 and BV 3192, respectively. The experimental results of adsorption capacity (X/M) for iodine-127 showed that two coal- based GACs were highest (208.6 and $139.1{\mu}g/g$), the coconut-based GAC was intermediate ($86.5{\mu}g/g$) and the wood-based GAC was lowest ($54.5{\mu}g/g$). The X/M of the coal-based GACs was 2~4 times higher than the X/M of the coconut-based and wood-based GACs.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.364-372
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• 2020

The "Master Plan for the Revitalization of Water in the Nakdong River" is designed for the fundamental improvement of water quality in the Nakdong River. The water quality and flow of the Nakdong River system tributaries was monitored in this study. Among the living environmental standard parameters of 195 rivers, BOD (Biochemical oxygen demand), T-P (Total phosphorus) and TOC (Total organic carbon) were assessed to analyze the water quality from 2012 to 2019. We examined the role of TOC. It was found that 12 rivers exceeded the water quality of the second grade (3.0 mg/L BOD standard, 0.1 mg/L T-P standard, 4.0 mg/L TOC standard) based on BOD and T-P concentrations: the Gumi stream, Gisegok stream, Yongha stream, Yongho stream, Changnyeong stream, Gajwa stream, Gwangok stream, Yeongsan stream, Toerae stream, Hwapo stream, Sangnam stream and Hogye stream. These rivers require strategies to improve the quality of the Nakdong River. Based on the ongoing project, it is possible to supplement the "Master Plan for the Revitalization of Water in the Nakdong River" and manage it after verifying it as a component of people's life and therefore used to establish water quality control measures.

• Journal of Environmental Science International
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• v.14 no.7
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• pp.649-655
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• 2005

Microcystis aeruginosa is common form of cyanobacteria (blue-green algae) capable of producing toxic heptapeptide (microcystin) that cause illness or death. The comparison of molecular genetic method with the morphological characteristics of cyanobacteria was conducted. We have designed PCR primers (JJM98F, JJM1141R) for cyanobacterial 16S rRNA and phycocyanin intergenic spacer (PC-IGS) gene domain. To confirm the production of microcystins, PCR primers for the N-methyltransferase (NMT) domain of microcystin synthetase gene mcyA were designed using 21 cyanobacteria strains Most of isolated strains from the Nakdong River was classified as Microcystis aeruginosa and the similarities were $99\%$ with M. aeruginosa AF 139292. $38.1\%$ of isolated strains contained microcystin synthesis gene. NMT (N-methyltransferase) were not detected in isolated strain in several strains, which means non-toxic. However, the NMTs of the strains were detected during the cultivation.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.2
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• pp.155-163
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• 2015

Many advanced treatment processes have been introduced to WTPs, however, the consumer confidence on tap water is still low and the percentage of drinking water directly from the tap is less than 2 %. One of the methods to improve the credibility of tap water is to introduce a drinking water certification system. By introducing the system, water treatment processes can be optimized, which in turn, can significantly improve drinking water quality. In this paper, 6 water quality parameters(i.e., turbidity, CT, residual chlorine, geosmin, 2-MIB, Mn) which have significant influences on tap water quality and consumer confidence were identified, and their recommended guidelines were proposed. 3-Star or 5-Star certification can be awarded to the WTPs which have met the certification criteria. The drinking water certification system can be carried out as a voluntary program among drinking water suppliers.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.933-942
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• 2012

The purpose of this study is to evaluate the degree of waterbody impairment according to the flow conditions and present to the appropriate water quality improvement alternatives using observed water quality and flow for Total Maximum Daily Load (TMDL) implementation at 39 unit watersheds the nakdong river basin. Observed water quality data for 7 years are divided into five cumulative flow frequency group and comparing the each observed water quality data and TMDL Target water quality (TWQ) the last evaluate the water quality is impaired group. We found that the cumulative flow frequency group-specific the average excess rate of V group was the highest (32.86%), followed by the IV group (26.04%), group III (23.36%), II group (22.67%), I group (20.70%), the degree of impaired waterbody tended to be inversely proportional to the flow rate. Resulted from cumulative flow frequency group of impaired water quality assessment, 13 unit watersheds are impaired from a group IV and group V affected by point sources. Therefore, improvement of sewage discharge and the initial composition of the riparian buffer zone are needed. Nakbon F, Namkang D and Namkang E within 13 unit watersheds are impaired from group II and III affected by non-point sources. Therefore, application of Best Management Practices (BMPs) is needed for these watersheds. Evaluation of impaired waterbody using Cumulative flow frequency group is able to determine the extent of the judgment to TWQ exceeded by the flow conditions and helps proper setting Standard flow and planning pollutant reduction for TMDL.