• 한국환경과학회지
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• 제3권3호
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• pp.285-296
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• 1994

The objective of this study was to examine and compare to transient response to quantitative and hydraulic shocks which produce equal changes in mass rate of organic feed in aerobic fixed-film process. The general experimental approach was to operate the system at several growth rates under steady-state(pre-shock) conditions, then to apply step changes during day 3 in dilution rate(hydraulic shock) , or feed concentration(Quantitative shock) at the same organic mass loading rate. Performance was assessed in both the transient state and the new steady-state (post- shock). Shock load of different type did not produced equivalent disruptions of effluent quality for equal increases in mass loading rate. Based on effluent concentrations, a hydraulic and a Quantitative shock at the same mass loading caused equal increase in total effluent COD, but the increase was primarily a result of suspended solids the hydraulic shock and COD in the quantitative shock. The time which effluent COD came to peak values were about 32~48 hours at the low organic loads and 52 ~ 72 hours at the high organic loads, respectively A quantitative shock produced a much greater increase in effluent COD than did a hydraulic shock at the same mass loading. Mean and peak values of effluent concentration weve increased in 2.8~4.2 times at low organic loading rate, 5.2~6.6 times at the high organic loading rate, respectively. Key words : Aerobic fixed-film reactor, Quantitative shock, hydraulic shock, mass loading rate.

• 한국환경농학회지
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• 제19권5호
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• pp.426-432
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• 2000

Field experiment was performed from August 1996 to December 1999 to examine the feasibility of constructed wetland system for sewage treatment in rural areas. A pilot system was installed in Konkuk University and the effluent of septic tank for school building was used as an influent to the wetland treatment basin. The system was composed of sand and reed, and operated continuously including winter time. Average removal rate of about 70% was observed for BOD, COD, and SS, about 50% for T-P, and about 25% for T-N. The reason for poor T-N removal might be due to high loading rate and short retention time. The system demonstrated satisfactory effluent concentration and stable performance in growing season. And it also worked adequately in wintertime even below $10^{\circ}C$ without freezing, and removal was still significant. The amount removed in BOD, COD, and SS was almost the same as in the growing season, and the amount removed in nutrients was about half of the one in growing season. Overall performance of the experimental system was compared with existing data base (NADB, 1994), and it was within the range of general system performance. As study period increased, removal rates for BOD, COD, SS, and T-P were consistently maintained and even enhanced, but removal rate for T-N decreased slightly. Wetland system was thought to be a feasible alternative for sewage treatment in rural area considering its low cost and low maintenance requirement. However, the effluent of the experimental wetland system often exceeded current effluent water quality standards, therefore, further treatment could be required if the effluent should be discharged to public waters. Wetland system of interest locates in rural area and is a part of rural ecosystem, therefore, ultimate disposal of reclaimed sewage for agricultural purpose or subsequent land treatment might be available and further research in this matter is recommended.

• 한국미생물·생명공학회지
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• 제23권6호
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• pp.755-762
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• 1995

A phenolic resin industrial wastewater containing about 41,000 mg/l of phenol and 2,800 mg/l of formaldehyde was biologically treated by a mixed culture GE2 immobilized on ceramic beads. This study was carried out with three experimental groups : Control-only added the sludge of papermill wastewater ; GE2 treatment-added GE2 to Control ; Ceramic treatment-applied ceramic carrier to GE2 treatment. When the original wastewater was diluted 80 times with aerated tap-water, influent COD$_{Mn}$ WaS 1,140 mg/l and that of the effluent was in the range of 22-35 mg/l, which was not much different among the experimental groups. However, at 20-times dilution, influent COD$_{Mn}$ was 4,800 mg/l and the effluent COD$_{Mn}$ of Control, GE2 treatment and Ceramic treatment was 179, 128 and 94 mg/l, respectively. COD$_{Mn}$, removal efficiency by Ceramic treatment was the highest, at 98.0%. At this time, the effluent phenol concentration of Control, GE2 treatment and Ceramic treatment was 10.71, 7.93 and 5.60, respectively. As the dilution times decreased, the removal efficiency of COD$_{Mn}$ and phenol did not change much, but COD$_{Mn}$ and phenol concentration of the effluent increased. Consequently, it is likely that the phenolic industrial wastewater containing phenol and formaldehyde can be biologically treated using a GE2 and ceramic carrier and that at 40-times dilution, the effluent completely meets the effluent standards for industrial wastewater treatment plant.

• 상하수도학회지
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• 제18권3호
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• pp.377-384
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• 2004

In the present study, a feasibility of an advanced oxidation process using UV/Hydrogen peroxide($H_2O_2$) system equipped with a medium pressure lamp for secondary effluent reclamation was investigated. Initial concentration of $H_2O_2$ and pH were changed to determine the optimum operation condition for the system. The removal efficiency of color was than 80% with 14.3mg/L of initial $H_2O_2$ and 5 minute of contact time in the UV/$H_2O_2$ system. The color removal was analyzed using first-order reaction equation. The dependence of rate constant (k) on initial $H_2O_2$ represented the rational relationship with maximum value. Residual $H_2O_2$ caused increase of effluent COD, since analyzing agent, dichromate, reacted with $H_2O_2$ in the sample. Therefore, excess initial concentration of $H_2O_2$ would significantly affect effluent COD measurement. At pH variation experiment, both residual $H_2O_2$ and color showed peak in the neutral pH range with the same pattern. Effect of $H_2O_2$ dose also enhanced color removal but raised residual $H_2O_2$ problem in the continuous operation UV system. In conclusion, these results indicated that medium pressure UV/$H_2O_2$ system could be used to control color in the secondary effluent for reclamation and reuse.

• 해양환경안전학회지
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• 제24권2호
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• pp.203-214
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• 2018

이염화이소시아뉼산나트륨(NaDCC) 주입 선박평형수처리설비(BWMS, ballast water treatment system)에 의해 처리된 배출수 내에는 브롬 및 염소계열의 활성물질과 소독부산물질(DBPs, disinfection by-products)들이 포함되어 있다. 본 연구에서는 NaDCC로 처리된 선박평형수가 해양환경에 미치는 생태위해성을 파악하기 위하여 생태독성시험(WET test, whole effluent toxicity test)과 생태위해성평가(ERA, ecological risk assessment)를 수행하였다. 배출수독성 시험종은 규조류(Skeletonema costatum, Navicula pelliculosa), 녹조류(Dunaliella tertiolecta, Pseudokirchneriella subcapitata), 로티퍼(Brachionus plicatilis, Brachionus calyciflorus) 및 어류(Cyprinodon variegatus, Pimephales promelas)로 8개의 해양 및 담수종을 이용하였다. 생태독성시험결과, 규조류 및 녹조류를 이용한 성장저해시험에서만 명확한 독성영향이 나타났으며 해수의 시험 조건에서 무영향농도(NOEC, no observed effect concentration), 최저영향농도(LOEC, lowest observable effect concentration) 및 반수영향농도(EC50, effect concentration of 50 %)는 각각 25.0 %, 50.0 % 및 > 100.0 %로 가장 민감한 영향을 나타냈다. 하지만 로티퍼 및 어류를 이용한 독성시험의 경우 모든 염분 구간에서 독성영향이 나타나지 않았다. 한편, 배출수에 대한 화학물질분석결과, bromate, isocyanuric acid, formaldehyde, chloropicrin과 trihalomethanes (THMs), halogenated acetonitriles (HANs), halogenated acetic acid (HAAs) 등 총 25개의 소독부산물질들이 검출되었다. ERA결과, 25개의 소독부산물질들 중, 지속성(P), 생물축척성(B) 및 생물독성(T)의 특성을 모두 보이는 물질은 없었다. 예측환경농도(PEC, predicted environmental concentration) / 예측무영향농도(PNEC, predicted no effect concentration) 비율은 일반적인 항구 환경에서는 모든 물질이 1.0을 초과하지 않았지만 선박 최 인접지역의 경우 Isocyanuric acid, Tribromomethane, Chloropicrin 및 Monochloroacetic acid가 1.0을 초과하여 위해성이 있을 것으로 나타났다. 하지만 실제 배출수를 이용한 생태독성시험결과의 NOEC (25.0 %)를 적용한 결과 NaDCC로 처리된 선박평형수가 해양에 배출되었을 때 선박 최 인접지역을 포함한 일반적인 항구 환경에 수용 불가한 생태위해성을 가지지 않는 것으로 판단된다.

• Environmental Engineering Research
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• 제14권3호
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• pp.174-179
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• 2009

The InSub system(applied for a patent) was developed, as it combined the indirectly aerated submerged biofiltration(InSub) reactor and Anaerobic/ Anoxic reactor. This system which can eliminate organism and nutrient materials at the same time, which is safe and economical to be maintained and managed is more simple process than the complicated existing biological advanced sewage treatment system. The most suitable HRT of this study showed 9 hours. As looking into the effluent concentration and removal efficiency of each item at 9 hours of HRT, each effluent concentration for $SS,\;BOD5,\;COD_{Mn},\;and\;COD_{Cr}$ was 1.46 mg/L, 7,09 mg/L, 9.84 mg/L and 16.42 mg/L. And their removal efficiency was 96.98%. 90.59%, 77.18% and 83.92%, respectively. Each effluent concentration of T-N and T-P was 10.42 mg/L and 1.04 mg/L. Their removal efficiency was 73.38% and 61.62%, respectively. This pilot plant experiment(the state was without the internal recycling.) followed a variety of HRT. The results confirmed that it was to be advanced sewage treatment system with high efficiency when it combined with the internal recycling.

• 한국수자원학회논문집
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• 제34권6호
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• pp.725-733
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• 2001

본 연구에서는 모형배수지를 이용하여 유출량의 변동여부와 도류벽의 설치여부에 따른 유출수의 잔류염소농도의 변화를 추적하였다. 모형배수지의 실험결과를 고찰해 보면, 유출량을 변동시킨 경우에 있어서 도류벽이 없을 때와 도류벽이 2개 있을 때, 유출수의 평균 잔류염소농도의 차이가 유출량을 일정하게 유지한 경우에 비하여 줄어 들었다. 이는 유출량 변동의 영향에 의한 것으로 유출량의 변동이 심한 배수지에 있어서는 유출량의 변동이 심하지 않은 정수지에서 보다는 도류벽 설치의 효과가 작은 것으로 판단된다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.191-194
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• 2001

The electrokinetic apparatus for remediation of the soil contaminated with Cs$^{+}$was designed. After kaolin clay was compulsorily contaminated by Cs$^{+}$ solution, the remediation characteristics by electrokinetic method were analyzed. After remediation experiment, the pH of the cathode side of the soil column was increased to 12.7 due to the generation of OH in cathode reservoir, but no hydroxide cesium form in the cathode side. Effluent rate from the cathode almost was constant and cesium concentration of effluent decreased with time passage. The 49% of a total of Cs$^{+}$ in the column was decontaminated for 0.4 day, the 72% of a total of Cs$^{+}$ in the column was decontaminated for 0.8 day, the 83% of a total of Cs$^{+}$ in the column was decontaminated for 1.2 days, the 89% of a total of Cs$^{+}$ in the column was decontaminated for 1.6 days, and the 93% of a total of Cs$^{+}$ in the column was decontaminated for 2.1 day Meanwhile, the predicted values of residual concentration by the developed model were quite similar to those obtained from experiments.m experiments.

• Journal of Radiation Protection and Research
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• 제43권3호
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• pp.124-129
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• 2018

Background: Effluent Concentration Limits (ECLs) were re-evaluated via direct calculation using dose coefficients based on radiation protection quantity introduced in Korea and the intrinsic breathing rates of Korean residents. Materials and Methods: The re-evaluated ECLs were compared with the domestic standards given in the Notice of the Nuclear Safety and Security Commission (NSSC), as well as with ECLs specified in the Code of Federal Regulations (CFR). Results and Discussion: The relative ratios of the re-evaluated ECLs to the currently applied domestic standards differed depending on the radionuclide type, but it was clearly shown that, for tritium ($^3H$) and radiocarbon ($^{14}C$), which significantly affect radiological dose to the public during the normal operation of nuclear power plants, the re-evaluated ECLs were higher than the domestic standards. This implies that Korean standards are relatively conservative. Conclusion: The re-evaluated results for each age group showed that $^{131}I$ (radioiodine), one of the significant radionuclides, had the lowest values, but nonetheless, the domestic standards for radioiodine were lower than the ECLs given in the CFR and the re-evaluated ECLs via a method given in the CFR.

• 한국농공학회지
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• 제41권5호
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• pp.86-92
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• 1999

Effluent concentration estimation equations for wetland system were developed throught statistical analysis of treatment wetland experimental data. Existin g empirical equations were reviewed for thier accuracy with experimental data, and compared with the estimatin equations. About 70 experimental data sets were used for multiple regression, and variables include influent concentration, hydraulic loading rate, average daily air temperature , and plant coverage. The estimatin equations developed for BOD5 , SS ,T-P, and T-N predicted effluent concentrations moderately well, and coefficient fo determination ($R^2$) for them was 0.74 , 0.60, 0.59 and 0.58 respectively. The equations obtained from same data but excluding plant coverage showed relatively lower $R^2$ than the former case, and it was 0.66, 0.52, 0.41 and 0.57 respectively. The EPA, WPCF , and Kadlec and Knight equations worked poorly and $R^2$ for them was significantly lower than the estimation equation developed in the study. The reason might be that the existing equations were oversimplified that they did ot include important parameters such as air temperature and plant coverage. Therefore, developing reasonable estimation equations from experiment under realistic condition is highly recommended rather than using exiting estimation equations.