• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3660-3671
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• 2022

A new methodology to derive a dose constraint for radioactive effluent from a unit of nuclear power plant (NPP) through retrospective assessment was developed to reflect operational flexibility in line with international standards. The new dose constraint can retain the safety margin between the offsite dose and the past dose constraints. As case studies, the new approach was applied to 24 Korean NPPs to address the limitations of the existing seven dose constraints that do not fully comply with current international radiation protection standards. Therefore, an effective dose constraint for Korean NPPs was proposed as no less than 0.15 mSv/y, which is comparable to the international practices and previous studies (0.05-0.3 mSv/y). Although the lower bound of the equivalent dose constraint was calculated as 0.17 mSv/y, it is not proposed in this study since the compliance with the derived effective dose constraint can prevent accompanied equivalent doses to any organs from exceeding equivalent dose limits. The new framework and the case studies are expected to contribute toward and support the revision of existing dose constraints for radioactive effluent from NPPs, ensuring better compliance with the current international safety standards as well as reflect the operational flexibility in practice.

• Journal of Environmental Science International
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• v.15 no.5
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• pp.439-446
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• 2006

The effluent discharge standards of industrial wastewater has become more stringent since 2003. Many industrial wastewater treatment plants has been upgraded to advanced treatment facilities. There are high concentrations of nitrate(>200 mg/L) and ammonium(>50 mg/L) nitrogen in the acrylic fiber wastewater of H textile Co. Wastewater from acrylic fiber industry containing acrylonitrile, which may affect the subsequent biological treatment process. Manufacturing of acrylic fiber also produces shock loadings. Excessive acrylonitrile and polymer debris produced in the polymerization process was screened, coagulated with CaO and settled down. A preaeration system was added to treat this high pH effluent to remove volatile organic compound and ammonia nitrogen by the air stripping effect. it was found that nitrification rate was not sufficient in the Anoxic/Oxic(AO) process. One denitrification tank was converted to nitrification reactor to extend HRT of nitrification. Nitrification rate of ammonia nitrogen was promoted from 32% to 67% by this modification and effluent nitrogen concentration was well satisfied with the effluent standards since then.

• Journal of Environmental Impact Assessment
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• v.14 no.5
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• pp.337-346
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• 2005

Pollution load allocation can likely be much controversial, which is essential to formulate the total water pollution load management plan. Existing rules(or guidances) in Korea, can provide no specific criteria for load allocation. Therefore, this paper studied(comprehensively) possible standards how or why to choose any particular allocation method, which was applied in the Gwangju City's load allocation for the satisfaction of set water quality goal. This load allocation is basically focused on the load reduction of domestic wastewater rather than industrial wastewater, because the land-use is strictly regulated and larger sources of pollution are few in the Gwangju City. This paper recommends the city to increase the capacity of sewage treatment plants, promote sewerage maintenance, and set higher effluent standards.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.2
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• pp.44-54
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• 1999

Agricultural water quality standards were reviewed through rice culture using treated sewage irrigation . The seqage from school building of Konkuk University was treated by a constructed wetland system, and theeffluent of the systeml was irrigated for rice culutre after nutrient concentration adjusted by dilution. Average concentration of COD, SS, T-N and T-P in irrigated water was 22.3mg/$\ell$, 6.5mg/$\ell$, 25.8 mg/$\ell$and 2.2mg/$\ell$, respectively. Treatment include irrigation of adjusted effluent with conventional fertilization (TWCF), adjusted effluent with no fertilization (TWNF). and effluent of the wetland system as it was with no fertilization (SWNF). These treatment plots were compared with control plot irrigated by tap water with conventional fertilization (CONTROL). Other environmentals for rice culture were identical for all the plots. Among them, TWCF showed the best growth rate and the highest yield, and constituents in the harvested rice showed not much difference among them. Which implies that irrigation with relatively high nutrient concentration compared to the current water quality standards may cause no adverse effect on rice culture and could be even beneficial . Although T-N for this study was 25 times greater than the current standards, rice culture wasnot adversely affected by irrigatino water quality and even beeter results were observed than the CONTROL. It could be mistakenly that clean irrigation water produces better agricultural product, however, it is not necessarily true. Irrigation water with moderate nutrient concentration can enhance the plant growth, and better result might be expected. Therefore, peer review and modification if necessary are needed to the current agricultural water quality standards, especially for the nutrient components.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.2
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• pp.249-255
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• 2014

So many drinking water treatment plants are under various difficulties by new reinforced effluent standards. Since the target turbidity, much higher than annual average, for designing sludge thickener have to be set to confront high turbidity season, the sludge at thickener should be put up for a long time during usual days. So the soluble manganese and chloroform may be formed under the anaerobic environment in the sludge thickener when the sludge retention time is longer with low turbidity. This phenomenon results in difficulties to keep regulatory level of the discharged effluent. For an effort to overcome the problems, a sludge aeration was successfully implemented into the thickening process. As a result, the final effluent quality and sludge volume were much improved; 41 % of manganese, 62 % of chloroform and 35 % of sludge volume. Additionally, effluent quality was improved ; 61 % of Manganese on aeration with pH control and we could make sure of stability effluent quality despite a long sludge retention time. We recommended the standard of installation sludge aeration equipment to nationally supply water treatment plant under effluent water quality problem ; Manganese, Chloroform, etc.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.470-474
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• 2001

A pilot study was performed at the experimental field of Konkuk University in Seoul, to examine the waste water treatment using constructed wetland and pond system. The effluent of the wetland system in winter often exceeded effluent water quality standards for sewage treatment plant, therefore, pond system could be applied to additional system. As a result, removal rate of $BOD_{5}$, SS was 84.4%, 81.5% and effluent concentration was 4.6mg/L and 5.0mg/L respectively, when surface water of pond system was discharged in March. So we concluded that pond system stored wetland effluent in winter and discharged surface water of pond system in March, so met water quality standard.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.139-148
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• 2002

Pilot study was performed to examine the feasibility of the pond system for further polishing of treatment wetland effluent from December 2000 to June 2001. The wetland system used for the experiment was highly effective to treat the sewage during the growing season, but it was less effective and its effluent was still high to discharge to the receiving water body. Therefore, the wetland effluent may need further treatment to prevent water quality degradation. Pond system could be used to hold and further polish the wetland effluent during the winter season and ots feasibility was evaluated in this study. Additional water quality improvement was apparent in the pond system during winter season, and the pond effluent could be good enough to meet the effluent water quality standards if it is properly managed. Timing of the pond effluent discharge appears to be critical for pond system management because it is a closed system and whole water quality constituents are affected by physical, chemical, and biological pond environments. Once algae started to grow in mid-April, constituents in the pond water column interact each other actively and its control becomes more complicated. Therefore, upper layer of the pond water column which is clearer than the lower layer my need be discharged in March right after ice cover melted. In the experiment, water quality of the upper water column was markedly clear in March than ant other times probably because of freezing-thawing effect. The remaining lower water column could be further treated by natural purification as temperature goes up or diluted with better quality of wetland effluent for appropriate water uses. This study demonstrated the feasibility of pond system for subsequent management of wetland effluent during the winter season, however, more study is needed for field application.

• Journal of Environmental Science International
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• v.15 no.7
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• pp.659-667
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• 2006

This research aims at applicability of adsorption process in order to satisfy the restricted Effluent Quality Standards for dyeing wastewater. The dyeing wastewater treated by biological process with carrier imbedded microorganisms was directly applied to the activated carbon adsorption in Process A, The dyeing wastewater treated by Fenton oxidation for the effluent of biological process was applied to the adsorption in Process B. It was found that the optimum conditions of adsorption with granular activated carbon are $20^{\circ}C$ and 120 minutes for the batch experiment. Langmuir equation was fitted better than Freundlich equation to the experimental data. The breakthrough time of adsorption column was determined by color rather than $COD_{Mn}$ for both Process A and Process B. The results revealed that the breakthrough time of adsorption for two processes was extended by the treatment of Fenton oxidation for dyeing wastewater treated by biological treatment than the direct application of dyeing wastewater treated by the biological treatment. Adsorption process can be applied in order to meet the restricted Effluent Quality Standards for dyeing wastewater.

• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.608-614
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• 2012

The effluent limitation of industrial wastewater is based on uniform regulatory criteria for effluent discharge facilities of all in Korea. But, an individual effluent limitation on each effluent discharge facility is widely applicable for regulation of industrial wastewater in US.EPA. To decide an individual effluent limitation, TBEL (Technology-based effluent limitation) and WQBEL (Water quality-based effluent limitation) are used. TBEL is based on the capability of a treatment technology to reduce the pollutants. WQBEL is based on ambient water quality standards. In this study, TBEL were derived for the pulp, paper and paper board manufacturing based on best practicable control technology currently available. It was suggested that effluent limitations were $BOD_5$ 4.7 mg/L, $COD_{Mn}$ 44.3 mg/L, SS 13.2 mg/L, TN 1.4 mg/L, TP 0.15 mg/L and best practicable control technology currently available (BPT) was neutralization, activated sludge treatment and coagulation and sedimentation for the pulp, paper and paper board manufacturing.

• 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.