• Journal of the Korean Society of Marine Environment & Safety
• /
• v.21 no.6
• /
• pp.617-636
• /
• 2015

The Mokpo coastal waters receive discharges from three artificial lakes(Youngsan, Youngam, Geumho) and other terrigenous freshwater inflows(streams, sewage treatment effluent, fresh groundwater), which exhibit very high concentrations of nutrients and/or organic matters. To understand spatial distributions of nutrients(DIN, DIP, DSi) and other water quality parameters(Chl-a, water temperature, salinity, DO, COD, SS), field surveys were conducted at 10 stations in the Mokpo harbor and adjacent estuaries on May, July, September, and November 2008 within 10 days following discharge events from artificial lakes. In this study, the freshwater flow rate influxed by the operation of sea dike sluice had significant influence on water qualities of the Mokpo coastal waters, although nutrient concentrations in other freshwater sources such as streams, sewage treatment effluent, and fresh groundwater were much higher. As a result of statistical analysis, DIN, COD, and Chl-a had a negative correlation with salinity. Therefore it was shown that discharge extents, time, and nutrients from the Youngsan lake were major impact factors dominating the spatial characteristics of nutrients and other water quality parameters in the Mokpo harbor and adjacent waters. However, despite non-discharge from the Youngsan Lake on September of this investigated period, it was observed that the nutrient addition was taking place in the lower layer of the estuary suggesting nutrient supply through different pathways. This result has emphasized the need to implement the combined assessment about the cumulative impacts on the Youngsan Estuary environment and ecosystem due to freshwater inputs derived from the artificial lakes as well as other terrigenous inflows, or benthic releases.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.11
• /
• pp.1945-1954
• /
• 2000

This study provides economical installation capacities for wastewater reclamation and reusing system in 7 areas of South Korea applying to contact aeration process using NPV(net present value) model based on cost-benefit. First. considering only private benefits. economical installation capacities for wastewater reclamation and reusing system applying to contact aeration process in household use were more than $500m^3/day$ in Pusan. $1,000m^3/day$ in Taegu. $2,000m^3/day$ in Kwangju. However. installation capacities in Seoul. Inchen, Taejon, and Ulsan were not optimal for $3,000m^3/day$. Therefore, supply ways of wastewater reclamation and reusing system in household use in the latter areas were more optimal local recirculation system than individual recirculation system. Economical installation capacities for wastewater reclamation and reusing system in business use were more than $100m^3/day$ in Seoul. Pusan. and Kwangju and which were $300m^3/day$ in Taegu, Inchen, Taejon, and Ulsan. Economical installation capacities for wastewater reclamation and reusing system in commercial use were more than $100m^3/day$ in Seoul, Pusan, Taegu, Kwangju, Taejon, and Ulsan, and which were $300m^3/day$ in Inchen. Second, considering only social benefits. economical installation capacity for wastewater reclamation and reusing system applying to contact aeration process was more than $100m^3/day$.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.7 no.3
• /
• pp.171-180
• /
• 2002

The temporal and spatial distributions of phosphorus have been investigated in the Gomso Bay, Korea. TP, PIP, TOP and DIP in sediment were found 548.8mg P kg$^{-1}$ , 426.1mg P kg$^{-1}$ , 122.6mg P kg$^{-1}$ , and 0.217mg P kg$^{-1}$ , respectively with a decreasing order of PIP>TOP>DIP. Any temporal or spatial trend has not been found on the distribution of TP in the sediment, except the high TP values near the mouth of Julpo-chun. We found seasonal patterns high TOP(28.90% of TP) and low TIP(71.10% of TP) in August, but low TOP(15.63% of TP) and high TIP(84.38% of TP) in November. There were three times higher DIP concentration in August than in November. Such case is probably not only due to the enhanced supply of DIP directly from the decomposition of organic matter from overlying water in summer, but also the released phosphate from the adsorbed particulate matter such as PIP under the low pH and Eh conditions at the subsurface layers of the sediment induced by the active microbial respiration of increased organic materials in summer. Primarily, the source of phosphorous from municipal sewage strongly influenced the early stage of the distribution of all the phosphorous in the Gomso tidal flat. Notwithstanding, through the processes of diagenesis in sediment, water temperature and organic contents probably functioned as the key parameters to control the temporal distributions of TOP, TIP and DIP in the Gomso tidal flat.

• Journal of Wetlands Research
• /
• v.11 no.1
• /
• pp.115-121
• /
• 2009

The hybrid constructed wetland(HCW) as tertiary treatment process of a bio industrial wastewater treatment plant was employed to estimate applications for the reuse of final effluent. Raw wastewater was sequently treated through chemical and biological treatment processes and the biologically treated water was flowed into the HCW. The HCW system was composed of two constructed wetlands connected in series; The one is the aerobic constructed wetland with natural air draft system whose driving force for air supply was the difference between the temperature of the air inside the wetland and the ambient air, and the other is the anaerobic/anoxic constructed wetland. Average influent concentrations of BOD, SS, T-N and T-P in the HCW were 53mg/L, 48mg/L, 34mg/L and 3mg/L, respectively. After being treated at HCW, final effluent concentrations of BOD, SS, T-N and T-P were 2.3mg/L, 1.2mg/L, 7.95mg/L and 0.83mg/L, respectively. Referring to a reuse standard for a sewage wastewater, final effluent could sufficiently be reuse as landscaping, washing or agriculture water. HCW system with the aerobic/anaerobic combined constructed wetland could be achieved a high removal efficiency because each constructed wetland was functionalized to be removed efficiently organics, nitrogen and phosphorus. HCW system could be estimated to be successful application as tertiary treatment process of a various industrial and municipal wastewater.

• Korean Journal of Environmental Agriculture
• /
• v.9 no.1
• /
• pp.23-37
• /
• 1990

In order to disclose the contamination of the Mushim-Cheon by pollutants in August and September of 1989 and to establish countermeasures, the collected water samples were analyzed to obtain the following results : 1. The water temperature of the period ranged from 25.8 to $30.8^{\circ}C$ acceptable for the growth of microorganisms and algae to allow the self-purification of the stream. 2. The pHs at the sites during the same period ranged from 6.5 to 8.5 which fall within the allowed values for the first grade water supplies except for site 14. 3. At site 18 which is the confluence of the sewer of the excretion disposal facilities and the main stream, the DO was observed to fall down to 0.7 ppm in September. 4. The BOD value reached a maximum of 62.1 ppm at site 18, which far exceeded the limit of 40 ppm, the allowed value for the discharges from the disposal facilities. In addition, the SS values were 200 and 520 ppm in August and September, respectively, which were three to seven times as high as the allowed limit of 70 ppm. 5. The high $NH_3-N$ value of 46.2 ppm at site 18 in September suggested that the water was heavily contaminated with excretions. 6. The BOD load of the sewage from site 12, the Sajik-Dong Sewer, in September was estimated to be about 0.306 ton/day. 7. The contamination of the influents, the family wastewater, and the discharges from the disposal facilities was greater than that of the main stream. 8. In the samples collected from site 12, the Sajik-Dong sewer at an interval of every two hours, a close correlation was observed between the pollutant load and the life cycle of the nearby inhabitants. 9. Compared with the results obtained from the water samples in 1979, it was observed that the water was heavily contaminated at site 12 (the Sajik-Dong Sewer, under the Chung Ju Great Bridge) and site 15 (Under the 2nd Uncheon Bridge) over the last 10 years, with little difference at site 9(Young Un-Dong water supply source).

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.1
• /
• pp.1-6
• /
• 2006

Biological nutrient removal(BNR) process used in this study, which was packed with EPS(expanded polystylene) media, has more many advantages in aspect of reducing hydraulic retention time(HRT) of the process and having less effect of temperature in the winter season than commercial process in the present. Bench-scale study was performed using domestic wastewater. In the results, it was observed that the T-N removal efficiencies in HRT 6 hr and HRT 4 hr were 55% and 51%, respectively, showing the small reduction (about 4%) of T-N removal efficiency according to shortening of HRT. In comparison of T-N removal characteristic in summer and winter seasons, it showed that T-N removal efficiencies in summer and winter seasons were 65% and 54%, respectively, showing the 11% lower T-N removal efficiency in winter season than in summer season due to deterioration of nitrification in winter season. In the studies of influent loading rate and C/N ratio, the process showed stable effluent quality under the condition of broad influent loading rate and C/N ratio. Therefore, it is anticipated that the developed process in this study could be applicable to small wastewater treatment plant in nutrient removal.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.8 no.3
• /
• pp.129-138
• /
• 1988

In order to develop the design and operational criteria in sewage treatment by indirect aerating submerged biofilter, experimental investigations were performed for the reasonable oxygen supply and effecting factors of treatment efficiency. The experiments were executed for the up-flowing synthetic wastewater and aerated water in the submerged biofilter at $20^{\circ}C$. The obtained results are as follows: 1) Appropriate mean diameter of gravels was about 11mm. 2) $BOD_5$ loading rate based on biofilter volume was more reasonable than that on surface area of gravel for operational criteria. 3) To remove the influent $BOD_5$ more than 90%, $BOD_5$ loading rate must be less than $1.0kg-BOD_5/m^3{\cdot}d$ and circulating flowrate must be more than $189m^3/m^3{\cdot}d$. 4) Reaction rate coefficient $K_1$ is related to diameter of gravel and circulating flow rate based on biofilter volume.

• Environmental and Resource Economics Review
• /
• v.20 no.1
• /
• pp.1-31
• /
• 2011

By employing Environmental Input-Output Table 2005, which has 76 intermediate sector and 21 energy sources, this paper analyses the flow of energy demand and $CO_2$ after estimating an induced $CO_2$ emissions from 76 industrial sectors. Index of $CO_2$ intensity($CO_2/GDP$) and other index of $CO_2$ intensity($CO_2/calory$) showed that final demand sector uses more high calory energy source. Intermediate sector used less environmental friendly energy source and emit more $CO_2$ at same calory. Industries those has high induced $CO_2$ emissions are Thermal Power($32.587CO_2-g/Won$), Cement($10.370CO_2-g/Won$), Road Transportation($7.255CO_2-g/Won$), Cokes and Other Coal Products($5.791CO_2-g/Won$), Steam and Hot water supply, Sewage, Sanitary services($4.575CO_2-g/Won$). It is shown that industry such as Iron and Steel which has low $CO_2$ intensity, high backward linkage effect and high forward linkage effect makes high induced $CO_2$ emissions. Environmental load and $CO_2$ emissions in overall economy will decrease when not high $CO_2$ intensity industry but also low $CO_2$ intensity industry makes lower $CO_2$ intensity.

• Journal of the Korean Geotechnical Society
• /
• v.34 no.7
• /
• pp.17-27
• /
• 2018

Sinkholes have occurred in various places around the world and concerns about public safety have been raised in recent years. Particularly, a ground subsidence may occur due to a variety of conditions when developing underground spaces. Ground subsidence refers to the sinking of the Earth's surface caused by the loss of the soil constituting ground due to a certain artificial cause in the ground. Ground subsidence is induced by artificial causes such as the leakage of water supply/sewage pipes and groundwater disturbance, and it is different from a sinkhole, where the sinking of the Earth's surface is induced by the cavity formed due to the melting of limestone in the ground with limestone bedrock. In recent underground development in the urban areas of Korea, damages to surrounding buildings have frequently led to many difficulties with civil complaints and compensation issues, and the collapse of some buildings has resulted in the loss of lives and property. Accordingly, the central government has legislated the Special Act on Underground Safety Management, which will take effect from January 1, 2018. This law specifies an underground safety management system for securing underground safety, under which underground safety impact assessment is performed for projects involving underground excavation work that exceeds a certain size, and safety inspection is regularly performed for underground facilities and the surrounding ground. In this study, the contents of the special act on underground safety management are reviewed, and the direction of development of underground safety policy for preparing preemptive underground safety management preparation and response system is suggested.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.39 no.6
• /
• pp.429-435
• /
• 2021

The integrated underground space map shows the underground facility(water supply, sewage, gas, electric power, communication, heating), underground structures (subway, underpass, underground walkway, underground parking lot, underground shopping mall, common ward), ground(drilling, coffin, geology) refers to a map constructed so that a total of 15 types of underground information can be checked at a glance on a three-dimensional basis. The purpose of this study is to develop a technology to correct the problem of curved surface processing and the unevenness of underground facility pipelines that occur in converting 2D underground facility data into 3D-based underground space integrated map(3D underground facility model). do it with. To this end, we first investigated and reviewed the domestic and foreign status of technologies that generate data on underground facilities based on three dimensions, and developed a surface correction algorithm and an unevenness correction algorithm to solve practical problems. Algorithms to verify the developed algorithm This applied correction program was developed. Based on the above process, the three-dimensional model of the underground facility could be produced identically to reality. This study is judged to have significance as a basic study to improve the utilization of the underground spatial integration map.