• 상하수도학회지
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• 제30권1호
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• pp.77-85
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• 2016

The characteristics of filter/adsorber granular activated carbon (F/A GAC) were investigated by measuring various parameters, which include surface area, pore volume, abrasion number, floater, and water-soluble ash. The correlation between parameters was also evaluated. Moreover, rapid small-scale column test (RSSCT) was conducted for adsorption characteristics. Thirteen F/A GAC were tested, and the average values of abrasion number and water-soluble ash were 88.9 and 0.15%, respectively. F/A GAC with the larger external surface area and greater mesopore volume had the lower abrasion number, which indicated that it was worn out relatively easily. Water-soluble ash of coconut-based GAC (about 2.6%) was greater than that of coal-based GAC (less than 1%), and the pH of solution was increased with GAC, which had the higher water-soluble ash. On the other hand, floater of thirteen F/A GAC was divided as two groups, which one group had relatively higher floater (2.7~3.5%) and the other group had lower floater (approximately 0.5%). The results of RSSCT indicated that coconut-based GAC (i.e. relatively higher water-soluble ash) had less adsorption capacity. Moreover, adsorption capacity of coal-based GAC with larger surface area and greater mesopore volume was superior to others.

• 생명과학회지
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• 제22권9호
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• pp.1237-1242
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• 2012

정수처리 공정에서 생물활성탄(BAC) 공정은 미생물의 유기물 제거능을 극대화시킨 일종의 생물여과 공정이다. 본 연구는 낙동강 원수를 이용하여 재질이 다른 생물활성탄을 사용하고 있는 정수장을 대상으로 세균 군집을 조사하였다. 실험결과 석탄계 재질의 BAC 부착세균 생체량 및 활성도가 각각 $1.20{\sim}34.0{\times}10^7$ CFU/g, 0.61~1.10 mg-C/$m^3{\cdot}h$의 범위를 보여 세균 생체량과 DOC 제거율은 석탄계 재질이 가장 높은 것으로 나타났다. 부착세균을 동정한 결과 Pseudomonas 속이 우점하였으며, 그 다음으로 Chryseomonas 속, Flavobacterium 속, Alcaligenes 속, Acinetobacter 속, Sphingomonas 속 등의 순으로 동정되었다. 그리고 Pseudomonas cepacia는 석탄계 재질, Chryseomonas luteola는 목탄계 재질의 우점세균으로 조사되었다.

• 한국도로학회논문집
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• 제8권3호
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• pp.115-127
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• 2006

현재 중부내륙 고속도로 시험도로(test road)에는 환경하중에 대한 도로 포장체의 환경적인 거동 특성을 파악하기 위하여 다져진 노상토에 WCR형태의 함수량계로 측정되는 체적 함수량이 현장 밀도의 영향등으로 부정확하게 예측되는 경향을 나타내고 있다. 따라서 본 연구에서는 흙의 특성과 현장 밀도를 고려하여 현장에 적합한 함수량 보정을 실내 및 현장시험을 각각 실시하고 이를 토대로 보정방정식을 제안하였다. 연구 결과 보정된 함수량은 현장의 측정치에 근접하게 판명되었다. 따라서 WCR을 활용하여 다짐된 노상토 지반의 체적 함수량을 측정시 사용된 흙의 종류 및 다짐조건 등이 고려되어야 한다.

• 한국물환경학회지
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• 제37권5호
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• pp.355-362
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• 2021

This study investigated the fate of dissolved organic matter (DOM) in a water reclamation facility (WRF) in Korea. The WRF consists of coagulation, sedimentation, microfiltration, and reverse osmosis (RO) components. The production capacity of WRF is 90,000 m³/day. The reclaimed water is reused as industrial water. We also characterized DOM in raw, processed, and finished waters based on analysis of dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm (UVA₂₅₄), fluorescence excitation emission matrix (FEEM), and DOC fractions via liquid chromatography-organic carbon detection (LC-OCD). Based on the results of DOC, UVA₂₅₄, and FEEM analyses, neither the coagulation/sedimentation nor the microfiltration at the WRF effectively removed DOM. The RO process removed more than 94% of DOM. The raw water (i.e., secondary treated effluent obtained from a wastewater treatment plant) exhibited tryptophan-like peaks, which are a promising marker of wastewater, in the FEEM analysis. Coagulation and microfiltration failed to eliminate the wastewater marker, whereas RO completely removed it. The raw water also carried high levels (89.4%) of hydrophilic and low-molecular weight substances, which are difficult to remove via coagulation-sedimentation or microfiltration. Humic substance was a major component of the hydrophilic fractions. Based on the LC-OCD analysis, RO effectively removed the humic and polymeric materials from DOM.

• 산경연구논집
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• 제11권10호
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• pp.39-48
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• 2020

Purpose: Management of water is a crucial issue globally and is becoming more critical due to climate change. The purpose of this study is to explore water resource management by considering price and water usage based on river basins and to suggest more efficient residential water demand management in South Korea. Research Design, data, and methodology: This study applied data of water usage and water price of 15 regions in four major river basins by considering up and downstream locations from 1997 to 2017 collected by Ministry of Environment in Korea. This study applied regression analyses, ANOVA, and 2-Way ANOVA to verify its claims. Results: The results found that effects of price on water usage showed significant in many cities. The results also showed that means of water usages differ based on location (upstream and downstream) and river basins. Conclusion: The findings provide important policy and management implications for the improvement of water resource management in terms of demand. The results also indicate that water price should be reconsidered by comparing water price levels with those of OECD countries. Furthermore, the results imply that water management in Korea needs to improve in terms of supply to cope with climate change.

• 상하수도학회지
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• 제10권3호
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• pp.100-114
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• 1996

Besides insufficient water, water contamination confronts us with 'water crises' of both quantity and quality. However, the daily water consumption per capita of Korea is greater than that of other developed countries. Because of the current low water price, which is lower than a half of production cost, not only does it become difficult to cope promptly with rapidly increasing water demand and water contamination, but it also causes waste of water. We should, therefore, switch over from supply side management-oriented policy to demand side management-oriented policy through a raise of the water rate. This study carries out a cost analysis based on fair return method which is the principle of water pricing in Korea, and it estimates, through equilibrium analysis, long run marginal cost(LRMC), which satisfies allocative efficiency and reflects true social cost to additional one-unit water supply. Based on the results, this study proposes that the estimated LRMC is the optimal price level in water pricing, which is the most important of the demand side management policies. In the end, water conservation effect, price pervasive effect, and social welfare effect are analyzed.

• 상하수도학회지
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• 제8권3호
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• pp.26-33
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• 1994

To slove the problems by the scum, which causes operational and water quality problems in water treatment plants, several researches were conducted based on the site investigations on twelve large water treatment plants, biological and chemical analysis of scum, analyzing raw water quality data. Two types of scum, which are from scum and floe scum, can be classified based on the analysis and site investigations. The major parameter generating floe scum was indicated as fine bubbles dissolved in the water. The fine bubbles dissolved in the water can be generated by over-saturated air in the water, adding aluminum surface as the coagulant, conducting the break point pre-chlorination and so on. The water spray method, which is one of the physical treatment methods for removing scum, was selected for conducting experiments on the removal efficiency in the flocculation basin of the real water treatment plant. The water spray method was successfully applied for removing scum with the advantages of using spiral nozzles in case of using the raw water rather than the cleaned water.

• 한국산업보건학회지
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• 제11권1호
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• pp.17-25
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• 2001

The purpose of this study is to substitute water-based painting materials for the current solvent-based ones used in motor-repairing process to minimize the exposure of organic solvents to the painters. This study assessed the exposure of organic solvents to the painters using water-based and solvent-based painting materials and compared compositions, painting processes and the health hazards of the application of these alternative painting mate rials. The results of this study are as follows. 1. solvent-based painting materials used in motor-repairing process consist of various organic solvents, which consist primarily of toluene, xylene, ethyl benzene, ethyl methyl benzene, trimethyl benzene, ethyl acetate, butyl acetate, methyl isobutyl ketone, 2-ethoxy ethanol, 2-ethoxy ethyl acetate and toluene-2,4-diisocianate and the others. These organic solvents are known as health-hazardous substances. But water-based painting materials are high-solid, low-solvent one sand consist of such two organic solvents as 2-butoxy ethanol and 2-heptanone and the others. 2. The painters us ing solvent-based painting mate rials in motor-repairing process are exposed to various organic solvents which consist of toluene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, trimethyl benzene, 2-ethoxy ethanol, and 2-ethoxy ethyl acetate. But the painters using solvent-based ones are only exposed to 2-butoxy ethanol and 2-heptanone. 3. By using water-based painting materials in stead of solvent-based painting materials containing health-hazardous organic solvents, the exposure of such organic solvents in the painter's breathing zone can be largely prevented. 4. This study recommends water-based painting materials as substitutes for the current solvent-based ones used in motor-repairing process to minimize the exposure of organic solvents to the painters.

• 한국환경과학회지
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• 제8권3호
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• pp.331-336
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• 1999

The monthly water quality data measured at 14 stations located in the Geum-River watershed were clustered into 2 to 7 clusters. Furthermore, factor analyses were conducted on Gabcheon and Yugucheon to characterize the water qualtiy, based on the information obtained from the results of culster analysis. The results of cluster analysis show that the water quality charactersitic of main stream of the Geum-River is somewhat different from that of substream of the Geum-River. Furthermore, the water quality characteristic of Gabcheon which is expected to have the most serious water quality problems in the Geum-River watershed shows the most different water quality characteristic from Yugucheon. Based ont he factor loadings in each factor, Gabcheon and Yugucheon have their own water quality characteristics. This is mainly because of composite factors such as different population density, industrial activities, and land use conditions in Gabcheon and Yugucheon subwatersheds.

• 제어로봇시스템학회논문지
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• 제15권7호
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• pp.688-693
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• 2009

In terms of water meter reading, the majority of 16 million houses use mechanical water meter in korea. So, a member of the utility's staff needs to access periodically the water meter and the value of the metered volume. However, due to the use of mechanical water meter, many issues have been appeared as cost, time, errors, accessibility, and readability. To settle these issues, we developed the walk-by meter reading system of digital water meter and outside indicator based on ubiquitous. And we could get the characteristics and the economical efficiency for water meter reading system. Thus, this study shows that the system can be widely used to the block system and the meter reading system for stable water supply.