• 수산해양기술연구
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• 제58권1호
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• pp.59-67
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• 2022

This study assessed the levels of water qualities and microbials contamination of inland olive flounder farms in Jeju in the summers from 2015 to 2017. Three farms (A-C) located in a concentrated area using mixing coastal seawater and underground seawater and one farm (D) located in an independent area using only coastal seawater were selected. Total ammonia nitrogen (TAN) reached a maximum of 0.898 ± 1.024 mg/L as N in the coastal seawater of A-C, which was close to the limit of the water quality management goal of the fish farm. TAN in the influent from A-C was up to three times higher than that of D, so that the discharged water did not spread to a wide range area along the coast and continued to affect the influent. TAN of the effluent in A-C increased by 2.7-4.6 times compared to the influent, resulting in serious self-pollution in the flounder farm. Heterotrophic marine bacteria in the influent of A-C was about 600 times higher than D, and the discharge of A-C was increased by about 30 times compared to the influent.

• 상하수도학회지
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• 제34권4호
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• pp.267-276
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• 2020

In this study, air scouring cleaning was selected and applied among 5 small blocks (S1~S5) in domestic S cities to analyze the cleaning effect of particles causing discoloration. In order to identify the cleaning effect, 10 locations were selected as water quality investigation point, such as the stagnant or water mains ends. Removal of solids, variation of particle components, weight and concentration were analyzed. And the level of the cleanness of the surface inside water mains using endoscope was investigated. As a result of analysis, the solids discharged after cleaning were mainly sand and gravel, pieces related to pipe materials, and corrosion products. As a result of analyzing the concentrated particles of the filter before and after cleaning, it was found that the change in discoloration on the filter was large. In addition, as a result of comparing the weight and the concentration of the particles, it was found that the particles causing discoloration were significantly removed after cleaning. From the results of the endoscopy, it was confirmed that most of the precipitated and accumulated dark yellow discoloration matters inside water mains were removed through cleaning. Therefore, it seems that the particles causing discoloration in water decreased after cleaning. Therefore, it is expected that, if properly cleaning was applied, matters that cause discoloration can be removed from the water mains, and customer's complaints can also be reduced through water quality improvement.

• 한국물환경학회지
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• 제22권5호
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• pp.943-951
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• 2006

Spatial distribution of water pollution in the Gap Stream was investigated from October to November, 2005. Sampling was conducted three times including effluents discharged from a wastewater treatment plant (WWTP) and a dam reservoir during the low-flow period. As a typical urban stream, total nitrogen and inorganic nitrogen concentrations increased toward downstream. Ammonia concentration was the highest in the treated water of the wastewater treatment plant and the lowest nitrate concentration was found in the effluent of the dam reservoir. A part of soluble reactive phosphorous (SRP) in total phosphorous was 22~54% in the upstream reach of WWTP in the Gap Stream whereas 68~73% in the downstream reach. Mean chlorophyll-a concentration ranged from 1.6 to $11.0{\mu}g/L$ and it tends to increase toward downstream except for WWTP effluent. As expected, untreated wastewater and WWTP effluent were suggested as the major sources of water pollution in the Gap Stream. In this study, the water pollution of the Gap Stream is a significant undergoing typical eutrophication, caused by excessive phosphorus and nitrogen nutrients from WWTP located in the watershed. As a result, the critical factor for the water pollution was evaluated to dissolved inorganic nitrogen and phosphorus nutrients. Particularly, SRP is a most important for the eutrophication. It suggest that may occur in the most urban streams of Korean peninsula. Therefore, because the necessity of water pollution management in the urban stream, inorganic N and P nutrients should be included as an essential component of water quality criteria in the advanced water quality project of Korean Government by enforcing of water quality assessment and total maximum daily loads (TMDLs).

• 한국환경보건학회지
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• 제10권1호
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• pp.13-20
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• 1984

The hospital wastewaters have to be so disposed as to prevent disease and to protect water resources from hazardous substances disinfectants, medicines, and chemicals. Polyvinylpyrrolidone-iodine complex (povidone-iodine) is widely used in the hospital as one of disinfectants. This study was carried out to manifest the effect of disinfectants in growth of activated sludge in treatment of the hospital wastewater by the activated sludge process. The results are as follow. 1. An average water quality of the hospital wastewater showed 7.2 in pH, 3.2 ppm in DO, 293.3 ppm in SS, 96.0 ppm in BOD, 151.1 ppm in COD, 0.4 ppm in povidone-iodine, 0.5 ppm in phenols, 5.4 ppm in surfactants, 1.6 ppm in o-phosphate, 4.6 ppm in $NH_3-N, 249\times 10^4$ counts/100 ml in coliform group organisms, and $1,369\times 10^2$ counts/ml in general counts of bacteria. And wastewater amounts discharged per bed was calculated 70 l/d/bed. 2. In batch culture activated sludge process, each of cresol and povidone-iodine was not effected in less than 0.1 ppm concentration, but the more concentration, the more inhibit the growth rate of activated sludge. In the mixture of two disinfectants, the growth was more inhibited the effect of single disinfectants. So that this reaction is considered as addition effect of two disinfectants. 3. The removal rates of the disinfectants-by continuous culture activated sludge process were 77.6% in 0.4 ppm povidone-iodine, and in BOD was 85.6%. 4. It is desirable that the hospital wastewater is planed in order to be discharged to two system separately, sewer from life system and wastewater from medical system. From those results, it has been concluded that the hospital wastewater has to be treated safely by the activated sludge process.

• 한국수산과학회지
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• 제51권1호
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• pp.1-7
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• 2018

We investigated patterns of antimicrobial resistance in Escherichia coli isolated from the water discharged from inland pollution sources in the Hansan-Geojeman and Jaranman-Saryangdo areas of Korea. A total of 217 strains of E. coli were isolated from 23 point-sources. These strains were tested for their susceptibility to 16 antimicrobial agents used in Korea for medical or veterinary therapy. The highest level of antibiotic resistance among the isolated strains was to tetracycline 10.6%, followed by ampicillin (3.2%), nalidixic acid (2.8%), rifampin (1.8%), trimethoprim (1.8%), trimethoprim/sulfamethoxazole (1.8%), chloramphenicol (1.4%), streptomycin (1.4%), cephalothin (0.5%) and gentamicin (0.5%). Resistance to at least one antimicrobial agent was present in 17.1% of the E. coli isolates. Only four of the isolated strains of E. coli showed multiple antibiotic resistance, which is defined as resistance to more than four antibiotics.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.104-104
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• 2018

Kori Unit 1 is the first permanent shutdown nuclear power plant in Korea and it is on June 18th, 2017. Spent fuel assemblies began to be discharged from the reactor core to the spent fuel pool(SFP) within one week after shutdown of Kori unit 1 and the campaign was completed on June 27th, 2017. The total number of spent nuclear fuel assemblies in SFP of Kori Unit-1 is 485 and their discharging date is different respectively. So, decay heat was evaluated considering the actual enrichment, operation history and cooling time of the spent fuel assemblies stored in SFP of the Kori Unit-1. The code used in the evaluation is the ORIGEN-based CAREPOOL system developed by KHNP. Decay heat calculation of PWR fuel is based on ANSI/ANS 5.1-2005, "Decay heat power in light water reactors" and ISO-10645, "Nuclear energy - Light water reactors - Calculation of the decay heat power in nuclear fuels. Also, we considered the contribution of fission products, actinide nuclides, neutron capture and radioactive material in decay heat calculation. CAREPOOL system calculates the individual and total decay heat of all of the spent fuel assemblies in SFP of Kori Unit-1. As a result, the total decay heat generated in SFP on June 28th, 2017 when the spent fuel assemblies were discharged from the reactor core, is estimated to be about 4,185.8 kw and to be about 609.5 kw on September 1st, 2018. It was also estimated that 119.6 kw is generated in 2050 when it is 32 years after the permanent shutdown. Figure 1 shows the trend of total decay heat in SFP of Kori Unit-1.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.44-60
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• 2021

In this paper, we validate the decay heat calculation capability via a two-step method to analyze spent nuclear fuel (SNF) discharged from pressurized water reactors (PWRs). The calculation method is implemented with a lattice code STREAM and a nodal diffusion code RAST-K. One of the features of this method is the direct consideration of three-dimensional (3D) core simulation conditions with the advantage of a short simulation time. Other features include the prediction of the isotope inventory by Lagrange non-linear interpolation and the use of power history correction factors. The validation is performed with 58 decay heat measurements of 48 fuel assemblies (FAs) discharged from five PWRs operated in Sweden and the United States. These realistic benchmarks cover the discharge burnup range up to 51 GWd/MTU, 23.2 years of cooling time, and spanning an initial uranium enrichment range of 2.100-4.005 wt percent. The SNF analysis capability of STREAM is also employed in the code-to-code comparison. Compared to the measurements, the validation results of the FA calculation with RAST-K are within ±4%, and the pin-wise results are within ±4.3%. This paper successfully demonstrates that the developed decay heat calculation method can perform SNF back-end cycle analyses.

• 한국환경농학회지
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• 제42권3호
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• pp.177-183
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• 2023

Rendering, is attracting attention as a technology that can stably and quickly process livestock carcasses. However, large amounts of livestock carcass solid residues are discharged in this process and limited methods are available for recycling them. In this study, rendered animal carcass solid residues were pyrolyzed to produce carbonized materials (350℃; RACR-C) and their chemical properties were investigated. Further, RACR-C were applied to cabbage cultivation for investigating their crop growth characteristics and soil improvement effects. RACR-C contained large amounts of fertilizer components such as nitrogen and phosphorus, and showed no toxic effects on the seedling growth of crops. The content of water-soluble nutrients released from RACR-C under the reaction time increased rapidly within 30 min, but was insignificant compared to the total content. Thus, most fertilizer components in RACR-C were not readily soluble in water. The optimal application amount for applying RACR-C to cabbage cultivation based on the changes in cabbage growth, inorganic content, and soil chemistry was 200 kg/10a. Overall, pyrolysis of solid residues after rendering livestock carcass to produce carbonized material as a soil improver is an effective method to recycle the waste discharged from the rendering process.

• 핵의학기술
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• 제14권1호
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• pp.28-34
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• 2010

갑상선암 환자가 증가함에 따라 고용량 방사성옥소 치료환자 또한 적체되고 있는 추세이다. 따라서 현재 시설의 수용 능력을 고려하여 치료할 수 있는 병실의 최대치를 산출해 보고자 한다. 본원에 입원하는 고용량 방사성옥소 치료 환자의 방출 오 폐수량과 오 폐수의 방사능을 측정하고 고용량 방사성옥소 치료 병실에서 대기 중으로 방출하는 공기 중의 방사능 농도를 측정한다. 측정된 오 폐수의 방사능과 방출하는 공기 중의 농도가 교육과학기술부에서 고시하는 기준인 배수 중의 배출 관리 기준 30 Bq/L 및 배기 중의 배출관리기준 3 $Bq/m^3$을 만족할 때 치료 가능한 병실의 최대치를 계산한다. 가장 보수적인 수치로 계산하여 환자 1명을 치료할 경우 배출되는 오 폐수의 평균 방사능의 농도는 8 MBq/L였으며, 정화조에서 117일의 감쇠 시간을 거친 후의 평균 방사능의 농도는 29.5 Bq/L였다. 환자 2명을 치료할 경우 배출되는 오 폐수의 평균 방사능의 농도는 16 MBq/L였으며, 정화조에서 70일의 감쇠 시간을 거친 후의 평균 방사능의 농도는 29.7 Bq/L였다. 또한 같은 조건일 경우 치료 병실에서 RI 배기 filter를 통과하여 방출된 공기 중의 방사능 농도는 0.38 $Bq/m^3$였다. 수용 능력을 고려하여 치료할 수 있는 고용량 방사성옥소 치료 병실의 최대치를 산출하여 현재의 시설에 적용하고 병실 내 구조개선 등으로 2인실로 운영한다면 적체되어 있는 환자의 치료 대기 기간을 단축할 수 있으리라 사료된다.

• 대한환경공학회지
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• 제36권10호
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• pp.719-723
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• 2014

수질오염총량관리제의 효율적인 시행을 위해 본 연구에서는 비점오염원의 분류, 비점부하량(발생, 배출) 산정, 비점 오염원 관리지역의 선정, 비점오염물질 관리 등을 포함한 비점오염원 관리방안을 제시하고자 하였다. 무엇보다도 먼저 점오염원과 비점오염원의 정의는 학술적 법률적 관점에 기초하여 명확히 구분 관리하여야 한다. 특히, 사업활동과 사람의 활동에 의해서도 환경피해가 발생하지 않는 임야, 초지, 하천 등은 별도로 자연배경오염원으로 구분하여야 한다. 비점오염원 발생 및 배출부하량의 원단위는 유역의 실제여건에 맞도록 우선적으로 변경하여야 하며, 비점오염원 발생 및 배출부하량의 산정방법은 유역의 강수량 및 강수 지속시간을 고려하도록 수정하여야 한다. 한편, 수질오염총량관리제를 시행함에 있어 비점 오염원 관리지역은 강우시 하천의 오염물질 농도가 중권역 목표(관리목표)를 초과하거나 초과할 우려가 있는 유역을 대상으로 하며, 전체 유역 가운데 초지, 임야를 제외한 도시지역, 농경지, 그리고 대지 가운데 비점오염물질의 배출밀도가 높은 지역을 비점오염원 관리지역으로 최소화하여 선정하여야 한다. 비점오염물질저감시설은 단위면적당 비점오염물질 배출량, 오염물질 초과농도 지속시간, 처리의 실현가능성, 점오염원 대비 처리비용 효과 등을 고려하여 단위면적당 비점오염원 발생부 하량이 많은 지역과 강우시 수질농도가 중권역 목표를 초과하는 유역에 설치하여야 한다.