• KIEAE Journal
• /
• v.12 no.3
• /
• pp.53-60
• /
• 2012

This research is an illustrative research to verify the thermo environmental change created after introduction of indoor pond through abridged model test and simulation analysis. Especially, temperature and comfort level are analyzed by adjusting factors like size of water space, distance length, and location. Summary of the research is as follows. First, the most effective size of water space is 7% of the indoor size, from southern side. Temperature reduction effect is about $1.6^{\circ}C$(5.5%), and for the comfort level, it is found that pmv index increases 8%. Second, based on the simulation of distance length with the sphere, it is more effective as it is close to the surface. If distance length is more than 0.5m, there is no effect on reduction of temperature and comfort level of indoor environment. Lastly, for the analysis by location of the introduced water space, simulation is undertaken by dividing the water space (14% of the indoor size) with front, side, rear and center types. Temperature reduction effect is found to be : front type ($-1.53^{\circ}C$), side type ($-0.82^{\circ}C$), rear type ($-0.44^{\circ}C$), center type ($-0.28^{\circ}C$), respectively. The indoor environment change data by introduction of water space, found in this research, is at initial phase, but it is deemed to be a basic data to refer when planning actual water space.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2001.10a
• /
• pp.11-14
• /
• 2001

This paper is studied on waste water maintenance management system for Integrated computing environment. This computing environment consist of Waste-Water Maintenance Management and GIS(Geographic Information System). This system can be developed by constructing Database which is set of rules occurring while management work of waste water system is processed. This system will help person who has responsible for making decision. Objective of such computing environment is providing efficient working environment for waste water facility management. Especially we analyzed problems of existing waste water maintenance management. We carried out efficient management of water facility and it will provide solution for major decision making work with low cost using Waste-Water Maintenance Management System

• Korean Journal of Ecology and Environment
• /
• v.50 no.3
• /
• pp.325-336
• /
• 2017

The ecosystem in the Gwangju Stream has taken a wide range of disturbance such as the discharging water of sewage treatment plant, the lake water and the river water from different water system over the past decade. This study was figured out some significant influence factors by analyzing the relationship between biotic and abiotic factors in the urban stream. Abiotic components included 15 water quality variables which were measured in five sampling sites along the stream from October 2014 to July 2015, whereas the benthic macroinvertebrates found in those sites were used to estimate various biotic indices representing the ecological status of the community. The results of correlation analyses indicated that abiotic factors by human activities affected on the inhabitation of benthic macroinvertebrates more than biotic factors. The results of cluster analyses and ANOVA tests also showed that biotic and abiotic characteristics were clearly different in season. The main influence factors of cluster analysis by sites were $NH_3-N$, EPT(I) and DO. It was considered that more various statistical analyses would be necessary to find some different relationships and influence factors between biotic and abiotic variables in the urban stream.

• The Journal of Engineering Geology
• /
• v.30 no.2
• /
• pp.119-129
• /
• 2020

Sand dam is a successful water harvesting method in mountainous areas with ephemeral rivers. The success is dependent on several factors including material type, hydrogeology, slope, riverbed thickness, groundwater recharge, and streamflow. In this study, the effect of a sand dam on the groundwater level in the Chuncheon area, South Korea was assessed using the MODFLOW model. Using the model, multiple scenarios were tested to understand the groundwater head before and after the construction of the sand dam. The effect of groundwater abstraction before and after sand dam construction and the sand material type were also assessed. The results show, the groundwater level increases substantially after the application of a sand dam. The comparison of model outputs, simulated groundwater head before and after sand dam application with and without pumping well, shows a clear difference in the head. The material type has also an effect on the groundwater head. As the conductivity of the material increases, the head showed a significant rise.

• Journal of Korean Society on Water Environment
• /
• v.22 no.1
• /
• pp.17-22
• /
• 2006

This study is about backwash condition and membrane fouling at continuous coagulation/ultrafiltration process in water treatment. The capacity of pilot plant was $0.06m^3/d$. The result of the test, Backwash cycle time and duration time had a significant effect on the efficiency of system and backwash. Backwash duration time was determined to be fixed in 30 seconds for the system with more than 95% recovery rate, It needed 30 minute backwash frequency. During the continuous operation, membrane fouling was analyzed by determining the filtration resistance ($R_i$) and cake layer resistance ($R_c$). At the initial stage, filtration resistance highly influenced the fouling behavior. But after 1.5 hours, cake layer resistance became more important than filtration resistant.

• Journal of Korean Society on Water Environment
• /
• v.30 no.3
• /
• pp.261-268
• /
• 2014

Four clays (both natural and commercial types) mainly used in Korea were tested for removal efficiency of Microcystis spp. and ecotoxicity on Daphnia magna and Vibrio fischeri. Four clays (clay A~D) were composed of 91.9~100% of sand (0.02~0.2 mm in particle size). Clay D consisted of lager particles than other clays. Major elements of the four clays were $SiO_2$ (45.3~62.8%), $Al_2O_3$ (18.5~29.7%) and $Fe_2O_3$ (5.4~7.9%). They contained kaolinite (clay mineral), quartz, muscovite, and so on. Clay C and D contained montmorillonite, one of the clay minerals improving clay-cell aggregation. For clay A, B and C, removal efficiency of Microcystis spp. was over 60% at 2 g/L. It reached about 100% at over 5 g/L. For clay D, it was over 60% and 95~100% at 5 g/L and 20 g/L respectively. After adding clays, pH decreased. The greatest drop of pH appeared at clay C. Except for addition of 100 g/L clay C, ecotoxicity on D. magna and V. fischeri didn't appeared at all dose of clays.

• Korean Journal of Ecology and Environment
• /
• v.49 no.1
• /
• pp.1-10
• /
• 2016

The increases of industrial and technological development and human activities have disturbed the balance of natural nitrogen (N) circulation. These phenomena have induced that large amounts of N are to be present in excess in air, soil and water environment. We investigated the effects of excess of reactive nitrogen ($N_r$) compounds on soil and water environment ecosystems through literature and case studies, and suggested the strategy of mitigating the acidification in soil and water ecosystems. $N_r$ moves to air, soil and water media, can be converted to different types, and interacts with other chemical compounds. As an efficient N management plan, the evaluation (application of monitoring and safety index) and the chemical restoration (research and development) of the acidification in soil and water environment ecosystems are required to minimize the effects of $N_r$ as well as policies to regulate the various emission sources and amounts of $N_r$.

• Journal of Korean Society on Water Environment
• /
• v.37 no.3
• /
• pp.190-203
• /
• 2021

Water quality, benthic macroinvertebrate communities, and other factors were investigated to explore the effects of the effluent discharge from a sewage treatment plant into Jwagwang stream in Busan in 2019. During the study period, the flow rate of this stream was in the range of 10,400 m³/day to 52,200 m³/day except for the discharge of about 24,000 m³/day of the effluent. After discharge, the flow velocity increased by about 65% and the water depth increased by about 40%. At sites downstream of the discharge point, BOD, COD, TOC, T-N, T-P, and other water quality values were worse than those of the upstream sites. The periphytic algal chlorophyll-a concentrations in the natural substrata were higher than those of the upstream sites, especially in May and August. However, at sites downstream of the discharge point, the individual numbers of Annelida were decreased and individual numbers of the insecta of arthropoda were increased. Also, species numbers and the diversity and dominance indexes were improved in the sites downstream of the discharge point. The functional feeding groups (FFGs) of collector-filterers were increased and the habitat orientation groups (HOGs) of sprawlers, burrowers, and clingers were especially increased at the sites with additional reclaimed wastewater effluent flow. Regardless of the effluent discharge, BMI, an indicator of ecological stream health using benthic macroinvertebrate species, did not show large gaps between the study points. Although the water quality of the sites downstream of the discharge point was much worse than those upstream, their ecosystem soundness was better than those of the upstream sites from an ecological perspective.

• Environmental Engineering Research
• /
• v.19 no.1
• /
• pp.41-45
• /
• 2014

The peels of Carya cathayensis Sarg. (PCCS) were treated under subcritical water conditions ($130^{\circ}C$ to $280^{\circ}C$ for 0 to 120 min). The extract from PCCS included reducing sugar, proteins, and compounds with radical scavenging activity. Addressing the reducing sugar that is a resource of bioethanol, we could maximize the reducing sugar under the subcritical water ($190^{\circ}C$ for 60 min) and obtain 0.24 g/g-sample together with 9.7 units/mg-sample of radical scavenging activity. The obtained extract was estimated to correspond to 1 L of bioethanol/100 g-sample. It was therefore considered that the treatment by subcritical water could yield reducing sugar and natural compounds with radical scavenging activity.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.11 no.2 s.23
• /
• pp.83-96
• /
• 2005

As recently, 'International convention for the control and management of ship's ballast water and sediments' was adopted, it is necessary to accept the international convention in Korea The movements of foreign countries for ship's ballast water control and management were investigated, and domestic environment-related laws were reviewed and compared regarding the discharge of industrial wastewater and ship's ballast water. Alternative measures of domestic legislation were suggested for acceptance of the international convention.