• 생태와환경
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• 제38권spc호
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• pp.54-57
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• 2005

It is important to assess the change of water environment in the present and past. In this study, present-day water quality standards are applied to the expressions in literary works to reconstruct the historical water environment including the quality. As the result, the historical reconstruction of water quality has been made distribution of water quality from 1905 to 1935 for the Sumida River in Tokyo.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1081-1083
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• 2007

The study in river basin has been performed for the identify water quality impaired stream segments, to create a priority ranking of those segments, and to calculate the heavy metal ion distribution for each impaired segment based on chemical and physical water quality standards. Two methods for modeling the potential area-specific heavy metal distribution are pursued in this study. First, a novel approach focuses on distance. Heavy metal distribution can be associated with a particular small geographic area. Based on the derived estimates an distribution map can be generated. Second, the approach is used the near watershed by means of kriging interpolation algorithm. These approaches provide an alternative distribution mapping of the area. The exposure estimates from both of these modeling methods are then compared with other environmental monitoring data. A GIS-based model will be used to mimic the hierarchical stream structure and processes found in natural watershed. Specifically, the relationship between landscape variables and reach scale habitat conditions most influential found in the Abandoned mine will be explored.

• 한국환경보건학회지
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• 제28권3호
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• pp.9-18
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• 2002

This study was to observe the occurrence of heterotrophic bacteria in terms of free chlorine residuals in two different water distribution systems belong to both K and Y water treatment plant. The data analyzed in this study showed that in distribution systems(DS), the free chlorine residuals were decreased from 0.10 to 0.56 ㎎/1 for K, and 0.51 and 0.78 ㎎/l for Y The decay of free chlorine were clearly higher in both March and August than those in January. The HPC in DS were ranged from 0 to 40 CFU/ml for K,0 to 270 CFU/ml for Y, on R2A medium. In particular, Its level was relatively high at consumers' ground storage tanks, taps and point-of-end area of Y, The predominant genera found in the distribution systems were Acinetobacter, Sphingomonas (branch of Pseudomonas), Microroccus, Bacillus, Staphylococcus. The diversity of heterotrophic bacteria was increased in the end-point area. Most of them were either encapsulated cells or cocci of gram-positve. In conclusion, the point-of-end area in distribution systems showed that the longer flow distance from WTP the greater diversity and higher level of heterotrophic bacteria due to the significant decay of free chlorine residuals.

• 한국환경보건학회지
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• 제28권2호
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• pp.51-60
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• 2002

Concerning the water quality management plan about Buk-stream, Ohsip-stream and Gagok-stream water systems in this research, which objectives of abstract is as follows. The result of cleanness degree evaluation of water quality in this research, the first grade was 91% shared in Buk-stream water system. The most point of the middle and upper stream of Buk-stream was maintain extremely clean water quality. Among the researched water system, the first grade of water quality in Ohsip-stream water system was most poor, its first garde rate was 68%. In all water quality check point of Gagog-stream water system was accomplished extremely clean water quality condition of first grade of BOD. The calculation result of pollutant loading density, which were 8.2, 21.5, 4.0kg/day.$\textrm{km}^2$. respectively and basin of Buk-stream and Gagok-Stream have high development potentiality.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1114-1119
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• 2004

The biofilms on pipe walls in water distribution systems are of interest since they can lead to chlorine demand, coliform growth, pipe corrosion, and water taste and odor problems. As such, the study described in this paper is part of an AWWARF and Tampa Bay Water tailored collaboration project to determine the effect of blending different source waters on the water quality in various distribution systems. The project was based on 18 independent pilot distribution systems (PDS), each being fed by a different water blend (7 finished waters blended in different proportions). The source waters compared were groundwater, surface water, and brackish water, which were treated in a variety of pilot distribution systems, including reverse osmosis (RO) (desalination), both membrane and chemical softening, and ozonation-biological activated carbon (BAC), resulting in a total of 7 different finished waters. The observations from this study consistently demonstrated that unlined ductile iron was more heavily colonized by a biomass than galvanized steel, lined ductile iron, and PVC (in that order) and that the fixed biomass accumulation was more influenced by the nature of the supporting material than by the water quality (including the secondary residual levels). However, although the bulk liquid water cultivable bacterial counts (i.e. heterotrophic plate counts or HPCs) did not increase with a greater biofilm accumulation, the results also suggested that high HPCs corresponded to a low disinfectant residual more than a high biofilm inventory. Furthermore, temperature was found to affect the biofilms, plus the AOC was important when the residual was between 0.6 and 2.0 mg $Cl_2/l$. An additional aspect of the current study was that the potential of the exoproteolytic activity (PEPA) technique was used along with a traditional so-called destructive technique in which the biofilm was scrapped off the coupon surface, resuspended, and cultivated on an R2A agar. Both techniques indicated similar trends and relative comparisons among the PDSs, yet the culturable biofilm values for the traditional method were several orders of magnitude lower than the PEPA values.

• 한국환경과학회지
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• 제17권10호
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• pp.1121-1127
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• 2008

The free-living amoeba and Acanthamoeba sp. are widely distributed in fresh water, soil, air and dust in the world. We studied distribution of amoeba from low Nakdong River(Mulgum and Maeri) and removal efficiency in water treatment process of Busan metropolitan city. During this investigation, water quality showed pH $7.4{\sim}9.6({\pm}1.1)$, water temperature $2.0{\sim}29.0({\pm}17)^{\circ}C$, turbidity $4.8{\sim}27.4({\pm}11.0)$ NTU, chlorophyll-a $10.3{\sim}109.0({\pm}44.3)\;mg/m^{3}$, BOD $1.7\sim4.9({\pm}2.6)$ mg/L, COD $3.1\sim-6.9({\pm}5.0)$ mg/L and total coliform $17\sim920({\pm}200.5)$ MPN/100 mL. The free-living amoeba were detected highly than Acanthamoeba sp., 11 out of 22 in raw water samples were positive (50%) for Acanthamoeba sp. from February 2005 to December 2005. The seasonal characteristics of tree-living amoeba and Acanthamoeba sp. in raw water were mainly distributed through the spring to the early fall. When tree-living amoeba and Acanthamoeba sp. were passed through the water treatment of pilot-plant, approximately 80% was sure to be removed through pre-ozonation, sedimentation, send filtration. 100% was removed after post-ozonation process. All of the isolated amoebas from Nakdong River were Acanthamoeba sp. AC311 18S ribosomal RNA gene with 98% nucleotide sequence homology.

• 상하수도학회지
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• 제12권3호
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• pp.118-124
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• 1998

To use chlorine residual as an surrogate parameter of the water quality change during the transportation in the water distribution system(WDS), the correct prediction model of chlorine residual must be established in advance. This paper shows the procedure and the result of applying the water quality model to the field WDS. To begin with, hydraulic model was calibrated and verified using fluoride as an tracer. And chlorine residual was predicted through simulation of water quality model. This predicted value was compared with the observed value. With adjusting the bulk decay coefficient(kb) and the wall decay coefficient(kw) according to the pipewall environment, the predicted chlorine residual can represent the observed value relatively well.

• 한국환경과학회지
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• 제15권5호
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• pp.447-459
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• 2006

Long-term trends and distribution patterns of water quality were investigated in the Cheonsu Bay of Korea from 1983 to 2004. Water samples were collected at 4 stations and physicochemical parameters were analyzed including water temperature, salinity, suspended solids (SS), chemical oxygen demand (COD), dissolved oxygen (DO) and nutrients. Spatial distribution patterns were not clear between stations but the seasonal variations were distinctive except COD, SS and nitrate. Twenty two year long-term trend analysis by PCA revealed the significant changes in water quality in the study area. Water quality during 1980's and early 1990's showed high SS, low nutrients and low COD which increased during the mid and late 1990's and early 2000's. Overall water duality in the Cheonsu Bay indicated the increase in nutrients and COD concentration.

• 환경영향평가
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• 제8권2호
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• pp.95-107
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• 1999

The organic contents of reservoir sediment can offer a good indicator to events in history of lake life. Reservoir sediment have many information of the past and future fingerprint about development direction of life cycle in biological animals. So, in this study we made an effort to know the distribution of organic contents in Daecheong reservoir sediment. Items for this investigations are such as follows: Loss on ignition, COD, Organic carbon, TN, TP, heavy metal contents, Loss on ignitions were determined in 6.44~15.91% and COD were determined in 1.606~6.859%, organic carbon in 1,077~3.743%. Contents of TP and TN were in the range of 0.083~0.757%, and 0.645~0.926%, respectively.

• 한국환경과학회지
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• 제23권9호
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• pp.1635-1642
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• 2014

Haloacetic acids (HAAs) concentrations have been observed to decreased at drinking water distribution system extremities. This decrease is associated with microbiological degradation by pipe wall biofilm. The objective of this study was to evaluate HAAs degradation in a drinking water system in the presence of a biofilm and to identify the factors that influence this degradation. Degradation of monochloroacetic acid (MCAA), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) was observed in a simulated distribution system. The results obtained showed that different parameters came into play simultaneously in the degradation of HAAs, including retention time, water temperature, biomass, and composition of organic matter. Seasonal variations had a major effect on HAAs degradation and biomass quantity (ATP concentration) was lower by 25% in the winter compared with the summer.