• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.3
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• pp.83-92
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• 1998

Field experiment was performed from August 1996 to January 1998 to examine the applicability of constructed wetland system for wastewater treatment in rural area. The pilot plant was installed in Kon-Kuk University and the school building septic tank effluent was used as an influent to the treatment basin. Hydraulic loading rate was about 0.1 6$0.16^3/m^2$ day and theoretical detention time in the system was 1.38 days. The treatment basin was composed of sand and reed. The influent DO concentration was low and many cases close to zero, but effluent concentration was higher than the influent which implies that oxygen was supplied naturally. The average concentration of influent BOD was 126mg/L, and with average removal rate of 69 % the average effluent concentration was 4Omg/L which satisfied the effluent water quality standard for the system of interest. The average influent concentration of COD was 2Olmg/L and average effluent concentration was 75mg/L with average removal rate of 60%. The performance of BOD and COD tends to deteriorate in the low temperature, and appropriate action needs to be taken during the cold winter time for stable operation. The average influent concentration of SS was 5Omg/L, and effluent was 1 1mg/L with average removal rate of 76% which satisfied the effluent water quality standard for the system of interest. The results for the regulated components, SOD and SS, from the experiment showed that constructed wetland system can meet the effluent water quality standards. The average influent concentration of total phosphorus was 25.6mg/L and average effluent concentration was 7.8mg/L with average removal rate of 63%. Not like the performance of the above components, average nitrogen removal rate was only 11.2% which is not satisfactory. Although, nitrogen is not regulated at this moment, it can cause many environmental problems including eutrophication. Therefore, nitrogen removal efficiency should be improved for actual application. From the result of the field experiment, constructed wetland system was thought to be an appropriate alternative for wastewater treatment in rural area.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.4
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• pp.579-589
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• 2012

To reduce extensive energy costs of the internal recycling for the purpose of denitrification in the advanced wastewater treatment, a post-treatment process using an electro-coagulation to treat nitrate in the secondary effluents is evaluated in this study. Removals of phosphorus and organics in the secondary effluents by the electro-coagulation were also evaluated to propose an alternative advanced wastewatert treatment process. A series of experiments of the electro-coagulation were carried out with the following 4 different samples: synthetic solution containing nitrate only, synthetic solution containing nitrate as well as phosphorus, secondary effluents from activated sludge cultivated in laboratory, and secondary effluents from real wastewater treatment plants. Removals of nitrate and phosphorus in the synthetic solution were 30 and 97 % respectively, which verified the feasibility of the process. Removals of nitrate, phosphorus and COD in the secondary effluents from the cultivated sludge in laboratory were 49, 90 and 19 % respectively. Removal efficiency of the total nitrogen, nitrrate, phosphorus and COD in the secondary effluent from real wastewater treatment plant were 50, 61, 98 and 80 % respectively. The removal of the total nitrogen was less than the nitrate as expected, which is due to the formation of ammonia nitrogen in the cathode. But the proposed scheme could be an energy saving and alternative process for the advanced wastewater treatment if further studies for the process optimization are carried out.

• Journal of environmental and Sanitary engineering
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• v.23 no.3
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• pp.23-30
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• 2008

This study was carried out to get efficient of nutrient removal effects on the treatment of paper making wastewater using submerged biological film process. The concentration of average BOD at raw wastewater was $324mg/{\ell}$ and COD was $435mg/{\ell}$. The average BOD of effluent was maintained $24.2mg/{\ell}$ and average COD was $37mg/{\ell}$. The concentration of average T-N at raw wastewater was $16.5mg/{\ell}$ and T-P was $1.2mg/{\ell}$. The average T-P of effluent was maintained $2.3mg/{\ell}$ and average T-P was $0.08mg/{\ell}$. The concentration of average SS at influent wastewater was $263mg/{\ell}$. The average SS of effluent was maintained $28.2mg/{\ell}$. The result of this experiment was wastage sludge did generated and the removal efficiency of nutrients were kept equilibrium.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.905-912
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• 2006

In this paper, simulation methods of the system dynamics model developed by Das et al. (1997) for activated-sludge wastewater treatment plants are illustrated in an attempt to determine the operating rules and the policies related to capacity expansion of an activated-sludge wastewater treatment plant. For existing conditions, the analyses were performed by varying activated-sludge return rate to observe changes in effluent water quality and treatment efficiency. The effluent water quality is also analyzed for various average daily inflow conditions and activated-sludge return rates. As a result, without expanding the aeration tank, maximum average daily inflow that can satisfy the effluent water quality standard of BOD $0.02kg/m^3$ was determined as $2,840m^3/hr$, subject to 100% of activated-sludge return rate while other factors remain constant. When the activated-sludge return rate is less than 100%, expansion of the aeration tank is necessary and minimum sizes of the aeration tank to satisfy the effluent water quality standard were determined for various activated-sludge return rates. In addition, the total operating and maintenance as well as unit treatment cost regression equations for activated-sludge wastewater treatment plants are suggested by using the cost data that are obtained from Water and Wastewater Division, Ministry of Environment. The regression analyses showed that the economies of scale phenomena exist in the operating and maintenance costs of activated-sludge wastewater treatment plants.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.41-50
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• 2010

The influent and effluent baffle configurations seriously affect the hydraulic characteristics of the secondary clarifier in wastewater treatment plant. In this study, those baffle configurations were optimized by computational fluid dynamics(CFD) analysis and particle image velocity(PIV) test in order to obtain uniform flow in inlet region and to minimize upflow velocity in outlet region of the secondary clarifier. Theoretical analysis using CFD showed that more uniform flow could be accomplished when the influent baffle was located closely to the inlet opening. Effects of effluent baffle configuration on the upflow velocity in the outlet region of the secondary clarifier were analyzed with four types of effluent baffles which are widely adopted for secondary clarifier design. From the CFD analysis, McKinney baffle(EB-2) was estimated to be the most effective for restraining the upflow velocity in the outlet region and these trends were identified by PIV tests. In addition, the McKinney baffle showed the most uniform overflow velocity distribution around the weir.

• Journal of Industrial Technology
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• v.16
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• pp.13-24
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• 1996

This research aims to investigate the effects of an internal carbon source in the denitrification of piggery wastewater. In this study, the raw wastewater and the effluent from each of anoxic basin and anaerobic basin were used as the internal carbon sources. The experiments were carried out in batch system and the results are as follows ; i) Denitrification rates were the highest in the raw wastewater and the lowest in the anaerobic effluent. ii) The piggery wastewater contained about 60 percent of the readily biodegradable organic(RDCOD), which led to a conclusion that the raw wastewater could be used as the internal carbon source for the denitrification. For the efficient denitrification, pre-denitrification process was found profitable. iii) In denitrification, alkalinity production rates were in the range of 3.4 to $3.6mgCaCO_3/mgNO_3-N$. iv) The denitritation of piggery wastewater came out to be possible, and the rate of organic carbon consumption decreased about 10 percent.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.57-64
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• 2019

We investigated influence of connected influent on the treatability of a wastewater treatment plant (WWTP), recently accepting effluent from a sludge carbonization facility. Based upon the pollutant loading rates (kg/d) of each connected influent, food waste leachate and livestock wastewater contributed to high BOD and COD loadings, while sludge carbonization facility effluent certainly contributed to T-N and $NH_3-N$ loadings. The nitrification rate in aerobic tank decreased to 55% with the carbonization facility effluent entering to the WWTP, while it was 89% with no carbonization facility effluent entering. The sludge carbonization facility effluent may need to be pretreated to reduce T-N and $NH_3-N$ loadings before entering to the WWTP for further treatment.

• Molecular & Cellular Toxicology
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• v.5 no.3
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• pp.265-271
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• 2009

Concentrations of industrial, agricultural and natural chemicals have been increasing in secondary effluents without their combined sub-lethal effects having been elucidated. In this study, two assays (the comet and acetylcholinesterase assays) were combined to evaluate the genotoxic and neurotoxic effects of effluent from the Noksan wastewater treatment plant (WWTP) on two local marine fish species (flounder and sea eel). The fish were exposed to WWTP secondary effluent that had been diluted with filtered seawater to final concentrations of 1%, 10% and 50%. Analysis of fish samples collected 3 and 5 days after exposure showed that DNA damage occurred in flounder exposed to 50% effluent and in sea eels exposed to 10% or 50% effluent. Furthermore, it was found that acetylcholinesterase (EC:3.1.1.7, AChE) activity decreased in both species when exposed to 10% effluent, indicating the presence of large amounts of genotoxic and neurotoxic chemicals in the effluent. Our results indicate that the comet and AChE assays are promising tools for biomonitoring of secondary effluents.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.281-288
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• 2005

BAT (Best Available Technology economically achievable) assessment is indispensible to effective management policy of industrial wastewater discharging facilities such as setting effluent limitations guidelines for individual industry based on the wastewater characteristics and treatment efficiency, making effluent limitations guidelines for new sources, and calculation of the reducible amount of emission load conforming to a total emission general plan and enforcement plan. This study reviewed foreign cases of BAT assessment and condition of domestic wastewater discharging facilities, and suggested BAT assessment guideline suitable for the domestic conditions. The major assessment factors and flow are; (1) Identification of pollution source characteristics, (2) Identification and survey on technology, (3) Selection of candidate technology, (4) Assessment of legislation adaptation, (5) Assessment of environmental factor, (6) Assessment of economical acceptability, (7) Total weighting value factor assessment on technological factor, and (8) Total assessment and final BAT selection. The result of this study can be utilized as a major policy data and a base of industrial wastewater management system.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.479-484
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• 2005

A GIS-based integrated system for reuse of effluent from wastewater treatment plants was developed in this study. The GIS-supported program classified attribute data which the effluent's quantity and quality and agricultural thematic map data according to the 5 big river basin area. From the database, showing the spatial variation of the water quality of the effluent, thereby proposing proper mitigation strategies over the watershed. Also, this system enables the users who is going to reuse the reclaimed water for their paddies to provide of all the wastewater treatment plant data and agricultural structures and thematic map data.