• KIEAE Journal
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• v.10 no.4
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• pp.9-17
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• 2010

The purpose of this study is to draw out objective bases for selecting various applicable facilities in case of the establishment of rainwater management strategies. To do so, sixteen facilities were selected from decentralized rainwater management systems that induce rainwater infiltration and detention as well as centralized end-of-pipe type infiltration and detention facilities in local areas. With these facilities, it attempted to evaluate them in terms of sustainability, pollutant elimination, flood control capacity and costs and subsequently analyzed correlations between each characteristic. The outcomes of the analysis were as follows: First was the analysis of characteristics between decentralized rainwater management systems and end-of-pipe rainwater management systems. From the decentralized rainwater management systems, the mulden-rigolen system and grass swale at street level had the highest in the total of the four items while the totals of the underground detention tank and temporary detention site were highest in end-of-pipe rainwater management systems. After analyzing the correlation between different types of facilities and each variable, it can be said that decentralized rainwater management systems have a higher correlation than end-of-pipe rainwater management systems in terms of sustainability whereas the latter are better in flood control capacity than the former. Second, the analysis of correlation in variables of each facility is as follows: first, there is a negative correlation between sustainability value and flood control capacity value; and there is a positive correlation between flood control capability and pollutants elimination. In addition, it revealed that the higher the flood control and pollutant elimination capability the higher the facility costs. Based on these assessments, it is possible to use them as objective selection criteria for facility application in case of site development project or complex plan.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.87-95
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• 2020

The worldwide shortage of water resources is a major environmental issue. Using pure water for drinking and domestic purposes is a bigger issue than other environmental issues. Industrialization and Urbanization have even polluted rainwater. In China, when it rains, rainwater is stored on the roof or other sources of storage for daily use resulting in pollution. Several studies have been conducted to treat rainwater. The objective of this study is to evaluate the efficiency of constructed wetlands by using ACF as a medium. So, this study aims to treat rainwater in Wuhan city through a Composite Vertical Flow Constructed Wetlands. First, rainwater was stored in the tank while it flows out of the roof, further it is processed in constructed wetlands. The constructed wetlands is consisted with plants Calamus and Chives, adding ACF (prepared from luffa) has achieved great results in this study. Results show that the pollutants have been removed to a considerable level, there were significant differences in removal rates under different HRT at 6h, 9h and 12h respectively. Therefore, Composite Vertical Flow Constructed Wetlands is recommended for total nitrogen and Ammonia nitrogen and total phosphorus.

• Asian Journal of Business Environment
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• v.10 no.4
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• pp.29-34
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• 2020

Purpose: Town of Woldia, a semi-arid region in the Northern Wollo region of Ethiopia, faces water supply shortage in general, though the town possesses a running stream of clean water throughout the year. This study is aimed at analyzing the possibility of using rainwater for water scarcity and non-potable water needs of the Woldia University. A careful study and analysis have been made to assess the feasibility of using rainwater in place of the tap water supply. Research design and methodology: This study was done inside the main campus of Woldia University located in Woldia town. The runoff water from the roof of buildings was studied, by the time of rainfall in the town. Also, the budget needed for implementing a rainwater harvesting system was calculated. Results: The findings of the study clearly indicates that the requirements of the water to use for flushing, cleaning, and washing toilets in the administrative buildings and classrooms can be satisfied by using rainwater as an alternative to tap water. Conclusion: Based on the results the study finds it is benefitable for the Woldia University to install the rainwater harvesting system at the earliest to solve the water problems prevailing in the current situation.

• 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.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1925-1928
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• 2007

Water cycle analysis was performed for Gunja basin located in metropolitan Seoul using Aquacycle model in order to assess the problems of urban water cycle. From the water cycle analysis of Gunja basin, it was found that 75% of total rainfall occurred in the form of surface runoff, and groundwater recharge only accounted for about 7%. This suggests serious distortion of water cycle which can be attributed to urbanization. Feasibility analysis of reuse scenarios such as rainwater use and wastewater reuse was then performed to examine their influences on improving the water cycle. From the analysis of water reuse options, it was shown that imported water supply savings of 13% can be achieved through rainwater use, and water supply savings of 31% through wastewater reuse.

• KIEAE Journal
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• v.7 no.4
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• pp.9-15
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• 2007

As environmental problems and water-shortage phenomenon become a global issue, many states look for the effective method to use water resources. So, decentralized rainwater management is recognized as a new water management system that rainwater can be infiltrated and used on-site. But it is little difficult to build a park, lake, and forest for evaporating rainwater in city because the land price of city is very high. In order to build an excellent infiltration system for a dwelling and a park in Korea, KICT has developed Linear infiltration system. This infiltration system is consist of first flush treatment, storage and infiltration, overflow control system. These elements are connected closely and working as a combined system. A storm sewer can be changed by the linear infiltration system. This study is to show real application idea about Linear infiltration system with improving some detail in apartments. For this purpose, we devide application idea into the artificial ground and the natural ground and each ground type, suggest a method to cooperate with the other landscape and linear infiltration system. Through this study, we came to recognize a recognition difference of an expert and a commoner about decentralized rainwater management.

• KIEAE Journal
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• v.11 no.2
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• pp.59-65
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• 2011

To analyze changes in the water-balance before and after using decentralized rainwater management facilities, this study carried out hydrologic modeling based on data including roof planting, rainwater use, infiltration and detention facilities applied to the sites. The results of the analysis are as follows: First, the total runoff quantity after facility installation was about 24% less than before. In particular, it showed that the surface runoff declined significantly. Second, the analysis of the effects of different decentralized rainwater management facilities revealed that the rooftop planting contributed to about a 3.5 times increase in actual evaporation than before. Third, the analysis of the effect of decentralized management facilities by different rainfall events showed that it turned to have about a 30% decreasing effect after facility installation for a monthly rainfall over 500mm or so and about 50% declining effect for a monthly rainfall about 200mm. As discussed above, the study confirmed that it is important to implement decentralized rainwater management facilities to improve inevitable changes in water-balance arising from development as it would be a significant alternative for sustainable urban development.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.4 s.117
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• pp.84-95
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• 2006

This study begins by examining the reason for the lack of urban planning that takes the water cycle into consideration. While there are institutions that support environmentally friendly development or smooth water circulation, these designs are not reflected in planning nor in the real world. After reviewing foreign case studies, policy suggestions and possible policy implications for Korea are derived. In Korea, there is not a sufficient level of relevant laws or institutions systematically established to make it possible to deal with rainwater in a decentralized way. Instead, facility standards or guidelines are considered separately for the control of water and for preventing natural disasters. And even though an environmentally friendly approach is stipulated in relevant laws in terms of spatial planning, there are no planning systems or implementation tools to actualize this kind of approach. The factors that make decentralized rainwater management possible in urban planning are analyzed based on the case study of Germany. Germany requires developers to plan in order to achieve ecological urban development. In addition, as a detailed implementation tool to promote conservation of the water cycle, the law provides for various kinds of measures such as restrictions on the proportion of impervious surface area according to the use of the land, required compensation measures for environmental degradation following development, introduction of a fee for rainwater runoff and the establishment of ecological landscape planning. The actual reason these measures can be implemented however is the provision of planning guidelines and design criteria for rainwater utilization, absorption and containment, and the construction of a database for various environmental information.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.333-341
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• 2014

To supply substitution water, $2m^3$ of capacity of rainwater harvesting system is designed calculating rainfall, catchment area and LPCD and has a effects to 34.4% of substitution water supply and 237 days of service day. Rainwater of drinking water quality was judged to be suitable except for bacteria problem, however, groundwater is exceeded in nitrate nitrogen, the evaporation residue and also bacteria, which means that the rainwater is suitable for use as water supply. In addition, to consider cost-benefit ratio, economic analysis conducted. The result is that B/C ratio of RWHS (10 years) is 1.70. It means total benefit is bigger than cost. Except to social factor in this study, there are a variety of benefit such as flood or drought prevention, educational effects inspiring water conservation awareness.

• Journal of the Korean housing association
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• v.25 no.3
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• pp.53-62
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• 2014

This paper investigates whether the use of Rainwater Harvesting Systems (RWHSs) to provide water for washing machines in Hong Kong residential buildings would be financially attractive. In such systems, rainwater is accumulated and reused for doing laundry, garden irrigation, flushing toilets, and even drinking. Thus, the analysis of RWHSs' financial feasibility is essential for construction projects. RainCycle is used to validate financial feasibility, considering particular circumstances and data relevant to the Hong Kong context. A range of different scenarios by adjusting three factors are evaluated: catchment area, water demand, and discount rate. It is suggested that $2,000m^2$ would be a suitable catchment area in a typical Hong Kong residential building and it is demonstrated how water demand and discount rate influence the financial performance of RWHSs. In particular, the financial performance of RWHSs is sensitive to discount rates. The results suggest that the RWH system would be worthwhile for buildings with a lower number of floors, but would barely achieve financial validation in Hong Kong's super high-rise residential buildings.