• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.31-37
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• 2005

One of the major obstacles confronted in promoting the rainwater harvesting is the concerns of acid rain and heavy metals. Although there are many data concerning the quality of rainwater precipitation for the study of acid rain, the study on the quality of stored rainwater has been limited. In this study, we monitored the quality of stored rainwater at Galmoe middle school, where a rainwater harvesting system is installed and in use for more than two years. We measured water quality parameters such as pH, Electro Conductivity(EC), Dissolved Oxygen(DO), and some metals (aluminium (Al), chromium(Cr), manganese(Mn), zinc(Zn), copper(Cu), arsenic(As), cadmium(Cd), lead(Pb)). The monitoring period was during one year from September 9th 2003 to August 5th 2004. It was observed that the average pH of stored rainwater is neutral. DO is similar to tap water and EC is lower than tap water. Metal Concentrations are within the concentration specified in Drinking Water Quality Standard. Overall, the stored rainwater quality is good enough for sundry use and there's no threat of acid rain and air pollution, if the rainwater harvesting system is well designed and maintained.

• Clean Technology
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• v.17 no.4
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• pp.353-362
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• 2011

In our nature, the utilization of rainwater is essential for healthy water recirculation. This is one of the solutions of the increment of impermeability surface according to the development of new cities; this study of the improvement of rainwater quality has been carried on through the improvement of collecting and restoring system of rainwater. The southwestern region of Daejeon City, the rainwater coefficient of run off was 0.40 and this number had computed to 0.59 after the development. After filtration of rainwater, the heavy metal (Cu, As, Cr, Fe, Mn) contents level were lower than underground water. Moreover, collected rainwater showed better quality than underground water in following criteria; hardness, permanganate consumption quality, chloride, evaporation residue, sulfates and nitrate nitrogen. This water quality met the gray water quality standards. The rainwater quality was still suitable to use as bathroom flushing and gardening after 100 days of storage. This study proved that modification (installation of cover with gutter to existing rainwater collection system, proper filtering, and installation of underground storage tank) of collection system could improve quality of water and maintain this approximately 100 days.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.461-468
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• 2010

This study investigated variation of rainwater quality by seasonal and storage duration of rainwater in Changwon city. Seasonally, the pollutants concentration of rainwater were higher in spring and winter. In the case of rainwater and storage rainwater quality, pH of rainwater was 4.3, storage rainwaters were 6.0 and Turbidity increased about 8 times from 1.82 NTU to 14.61 NTU. The changes of storage water quality during the storage period, initial KMnO4 consumption rainwater was exceeded drinking water standard. Total solid in rainwater was detected as 116 mg/L, it tended to stable at around 70∼80mg/L after storage period for a 6day.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.131-138
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• 2007

A rainwater utilization facility consists of its catchment area, treatment facility, storage tank, supply facility and pipes in general. The rainwater storage tank which occupies the largest area of the facility has been usually considered quantitatively for determining the storage capacity. Hence, there is little information on water quality improvement by sedimentation in a rainwater storage tank in operation. In this study, we measured the rainwater quality in a rainwater storage tank in operation during late spring and summer, and showed water quality improvement of turbidity removal of 25~46% by sedimentation in a rainwater storage tank under a fixed water level without inflow and outflow after runoff ceased. It is necessary to have a considerable distance between the inlet and outlet of the tank and, if possible, it is recommended that the design should allow for an effective water depth of over 3 m and supply rainwater near the water surface. The operation method which increases the retention time by stopping rainwater supply for insuring low turbidity is recommended when the turbidity of rainwater runoff is high. And also more efficient operation and maintenance of the rainwater utilization facility is expected through the tailored design and operation of the facility considering particle removal and behavior.

• Journal of Environmental Science International
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• v.12 no.3
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• pp.275-279
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• 2003

A water quality analysis of rainwater collected from catchment equipment(2m${\times}$1m) was conducted to determine its suitability for domestic purposes, in this study. As the results of analysis, the pH of rainwater was 6.3${\pm}$0.3, and the turbidity of rainwater was over the 5 times than drinking water guidelines. For the usage of rainwater as the domestic and drinking water, the rainwater is need to treat. The analysis value of BOD was about 3 mg/L and the values of heavy metal as the Pb, Cd, Fe, Mn, Cr$\sub$6/$\^$+/and Cu was satisfied with drinking guidelines. Overall results of analysis support the possibility of rainwater as the domestic and drinking water.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3B
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• pp.355-361
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• 2008

A water quality analysis of rainwater collected from catchment equipment ($2m{\times}1m$) was conducted to determine its suitability for domestic purposes, in this study. As the results of analysis, the pH of rainwater was $6.3{\pm}0.3$, and the turbidity of rainwater was over the 5 times than drinking water guidelines. For the usage of rainwater as the domestic and drinking water, the rainwater is need to treat. The analysis values of heavy metal as the Pb, Cd, Fe, Mn, ${Cr_6}^+$ and Cu was satisfied with drinking guidelines. Rainwater quality was improved in the rainfall duration. Overall results of analysis support the possibility of rainwater as the domestic and drinking water.

• Journal of Wetlands Research
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• v.14 no.1
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• pp.11-20
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• 2012

The aim of this study is to accumulate the data about the roof-harvested rainwater quality characteristics for the better rainwater management. According to the results of rainwater quality indicators (pH, COD, TSS, T-N, T-P, $NH_4$-N, $NO_3$-N, enteric bacteria, heterotrophs, Pb, Cd, Cu), the rainwater qualities of the first flush of roof-harvested was the most polluted about 2 or 3 times (more than 100 times in microbial contamination) compared to the qualities of directly collected rainwater. In the first 10 min flush, over the 60% amounts of contaminant were released from the roof during 30 minute rainwater monitoring. Through statistical factor analysis, relatively close items(variables) can be categorized. It is expected that the continuous monitoring of the roof-harvested rainwater will help to design the safe and economical rainwater storage system in Korea.

• Journal of Korean Society on Water Environment
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• v.27 no.3
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• pp.300-305
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• 2011

This study aimed at analyzing the runoff quality by the layer thickness and material of soil roof to make best use of the rainwater falling on it in terms of safety and efficiency and resulted in the following assessments. It turned out that the concentrations decreased more in T-N, $NO_3$-N, $NH_4$-N, T-P and $PO_4$-P in roof rainwater except 30 cm for the RW1 soil roof after passing through it than those of first rainwater. On the other hand, the concentrations in rainwater passing through gravel roof turned out to be equal or same to those of the first rainwater. As a result of analysis of metallic stuff in runoff, there was no indication of Cd, Cr, Mn and Pb as well. The concentration of Cu, Fe and Zn in rainwater through soil roof became less than that of the first rainwater. In this research, the soil roof showed the good efficiency in lowering the concentration of such components as nitrogen, phosphorus and metals. Based on the results from this work, more practical study would be required further in the future in relation to soil roof when installing the rainwater-utilizing facilities.

• Journal of Wetlands Research
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• v.16 no.1
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• pp.33-39
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• 2014

The purpose of this study is to monitor the rainwater flowing from the roof of buildings and to maximize the effectiveness of the rainwater storage. This study also analyses the changes in rainwater characteristics before and after subsequent chlorination disinfection. The stored rainwater was disinfected by chlorine and then analyzed for COD, TN, TP, enteric bacteria, and general microbial population changes over time. There was an observed 99% reduction of enteric bacteria and common microbes within two weeks after chlorine injection. Thus, chlorine disinfection of rainwater improves water quality for long-term storage and future use.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.1
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• pp.66-72
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• 2004

In this study, quantity and quality of collected rainwater by sand, gravel, soil, lawn and concrete surface, as collection materials were investigated and Rainwater Collection Prediction Model was developed to predict the amount of collected rainwater. The quantity of collected rainwater in concrete surface, gravel, sand, soil and lawn collection system was 1,067L(93.2%), 1,006L(87.8%), 902L(78.8%), 800L(69.9%), 788.5L(68.8%) for 8 months period, respectively. The average turbidity of collected rainwater in concrete surface, gravel, sand, soil and lawn collection system was 3.2NTU, 2.2NTU, 1.9NTU, 1.7NTU, 1.5NTU for 8 months period, respectively. For sand collection material, predicted amount by the Model and actual collected amount were 931.5L and 902L, which were very closed. For gravel collection material, predicted amount by Model and actual collected amount were 1,028.21. and 1,006L, which were very closed. To simulate the optimal rainwater storage volume, the rainfall and evaporation data in Dae-jeon city were used. For sand collection system with 30m2 area, the maximum storage volume was $17m^3$ and 62% of the year was secured for use of 240L/day.