• 상하수도학회지
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• 제20권1호
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• pp.115-121
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• 2006

The purpose of this study was to investigate applicability of pretreatment on the existing biological treatment for domestic wastewater reclamation. From Jar Tests, it was found that optimum dosage of coagulant was PAC 0.5mg/L and $FeCl_3$ 180mg/L for urban sewage. In this study, PAC 0.5mg/L was selected considering sludge production and the amount of coagulant required. In a continuous experiment performed with combining chemical coagulation and biological treatment, a considerable removal efficency was obtained in term of BOD, SS, T-N, T-P and ABS. When the raw sewage was supplied into the pre-chamical treatment facility, the removal of BOD and SS was 48.3% and 81.1%. However T-N removal was very low which means T-N consists of $NH_3-N$ mostly. T-P was almost completely recluced by the chemical addition. The effluent BOD & SS was 57~76 and 21~43mg/L, which could reduce the size of biological treatment facility. From the cost estimation pre-chemical treatment could save around half of the area required for biological treatment with post ceagulation.

• 한국환경과학회지
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• 제19권3호
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• pp.371-377
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• 2010

The purpose of this study is to investigate treatment efficiency in dyeing wastewater treatment by the high rate aeration system(HRA) and a combination of the HRA with magnetized wastewater treatment system(MWS). At the hydraulic retention time of 16hr, 24hr, 30hr, BOD removal efficiencies of HRA system were 93%, 96% and 98%, combination of the HRA with MWS system were 94%, 96.8% and 98.2%, respectively. In ease of COD, at the hydraulic retention time of 16hr, 24hr, 30hr, COD removal efficiencies of HRA system were 66%, 77.1% and 83.1%, combination of the HRA with MWS system were 70.2%, 80.1% and 86.6%, respectively. The comparison of the HRA and combination of the HRA with MWS, effluent BOD of the former was 22.7mg/${\ell}$ and the latter was 19.4mg/${\ell}$, theretore biological treatment efficiency identified to increase by the MWS.

• KSBB Journal
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• 제15권4호
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• pp.370-374
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• 2000

제약폐수처리장과 판지폐수처리장의 활성슬러지 또는 폭기 조 media로부터 분리한 균들과 type culture들을 첨가할 경우 제약폐수와 판지폐수의 처리에 도움을 주는지를 알아보았다 폐수에 균틀을 배양하였을 때, 제약폐수에서는 charcoal m media로부터 분리한 Bacillus종 (PC-3)이 특이하게 잘 증식하 여 24시간 배양후의 생균수가 $1.1{\times}10^6m/L$를 나타내었으며, 판지폐수의 경우에는 type cultute인 Bacillus subtilis KCTC 1028이 가장 잘 증식하여 24시간 배양후의 생균수가 $1.1{\times}10^7m/L$를 나타내었다. PC-3률 첨가하는 제약폐수의 회분식처 리실험에서 균첨가효과가 확인되었으며8일째의 첨가구의 C COD제거율이 무첨가구의 COD제거율에 비해 18% 더 높았다. Bacillus subtilis KCTC 1028 을 첨가하는 판지폐수의 회 분식처리실험에서도 균첨가효과가 확인되었으며, 24시간후의 첨가구의 COD제거율이 무첨가구의 COD제거율에 비해 14% 더 높았다. Bacillus subtilis KCTC 1028은 전분질원료 주정 폐 액에서 잘 증식하였으므로, 전분질원료 주정폐액을 Bacill따 s subtilis KCTC 1028의 경제적인 생산배지로 이용할 수 있다.

• Journal of Ecology and Environment
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• 제41권11호
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• pp.318-327
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• 2017

Background: A typical sewage treatment plant is designed for organic and nutrient removal from municipal sewage water and not targeted to eliminate micropollutants such as pesticides, pharmaceuticals, and nano-sized metals which become a big concern for sustainable human and ecological system and are mainly discharged from sewage treatment plant. Therefore, despite contaminant removal by wastewater treatment processes, there are still remaining environmental risks by untreated pollutants in STP (sewage treatment plant) effluents. This study performed aquatic toxicity tests of raw wastewater and treated effluents in two sewage treatment plants to evaluate toxicity reduction by wastewater treatment process and analyze concentration of contaminants to reveal potential toxic factors in STP effluents. Methods: Water samples were collected from each treatment steps of two STPs, and acute and chronic toxicity tests were conducted following USEPA (United States Environmental Protection Agency) and OECD (Organization for Economic Cooperation and Development) guidelines. Endpoints were immobility for mortality and reproduction effect for estrogenicity. Results: Acute $EC_{50}s$ (median effective concentration) of influents for Seungki (SK) and Jungnang (JN) STPs are $54.13{\pm}32.64%$ and $30.38{\pm}24.96%$, respectively, and reduced to $96.49{\pm}7.84%$ and 100%. Acute toxicity reduction was clearly correlated with SS (suspended solids) concentration because of filter feeding characteristics of test organisms. Chronic toxicity tests revealed that lethal effect was reduced and low concentration of influents showed higher number of neonates. However, toxicity reduction was not related to nutrient removal. Fecundity effect positively increased in treated wastewater compared to that in raw wastewater, and no significant differences were observed compared to the control group in JN final effluent implying potential effects of estrogenic compounds in the STP effluents. Conclusions: Conventional wastewater treatment process reduced some organics and nutritional compounds from wastewater, and it results in toxicity reduction in lethal effect and positive reproductive effect but not showing correlation. Unknown estrogenic compounds could be a reason causing the increase of brood size. This study suggests that pharmaceutical residues and nanoparticles in STP effluents are one of the major micropollutants and underline as one of estrogenic effect factors.

• 수산해양기술연구
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• 제52권3호
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• pp.271-275
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• 2016

Recently, pollution problem in coastal water has become more serious and pollution including red tide serves as a main reason for reduction of fishes resources. Particularly, nutrients such as nitrogen and phosphorus are the most serious pollutants. Normally, biological wastewater treatment process is used in removing such nutrients. However, it is difficult to adopt the biological wastewater treatment process to a small-scale fish processing factory in case of using seawater as wash water. Thus, removing nutrients through struvite crystallization is investigated in this study for treating shrimp processing wastewater. Experiments were conducted by varying molar ratio of $Mg^{2+}:NH^4-N:PO^4-P$ from 1:1:1 to 2:1:1. It can be concluded that optimum molar ratio is 1:1:1. Struvite crystallization process is compared with chemical coagulation process using PAC and struvite crystallization process is proven as the more effective process in removing nutrients from wastewater. In view of results obtained from these experiments, struvite crystallization process is a promising method in removing nitrogen and phosphorus from wastewater; however, not so good in removing organics. Thus, struvite crystallization process is suitable as the pre-treatment process in treating shrimp processing wastewater and additional biological process is needed to remove organics.

• 상하수도학회지
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• 제34권6호
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• pp.445-462
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• 2020

Industrial wastewater often contains a number of recalcitrant organic contaminants. These contaminants are hardly degradable by biological wastewater treatment processes, which requires a more powerful treatment method based on chemical oxidation. Advanced oxidation technology (AOT) has been extensively studied for the treatment of nonbiodegradable organics in water and wastewater. Among different AOTs developed up to date, ozonation and the Fenton process are the representative technologies that widely used in the field. Based on the traditional ozonation and the Fenton process, several modified processes have been also developed to accelerate the production of reactive radicals. This article reviews the chemistry of ozonation and the Fenton process as well as the cases of application of these two AOTs to industrial wastewater treatment. In addition, research needs to improve the cost efficiency of ozonation and the Fenton process were discussed.

• 상하수도학회지
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• 제28권6호
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• pp.747-753
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• 2014

• 상하수도학회지
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• 제19권1호
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• pp.61-67
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• 2005

The objective of this study was to investigate community structure of attached algae and microbes in sedimentation basin of water and wastewater treatment plants by using respiratory quinone profile. There was an evident difference, in microbial community structure and attached algae species, between inclination plate settler and drainage canal in the sedimentation basin. The algae was composed of species in following order; Chlorophyceae>Bascillariophyceae>Cyanophyceae. The dominant quinone types of attached microorganisms in the wastewater treatment plant were plastoquinone (PQ)-9, vitamin(V)K-1 followed by UQ-8, but those for water treatment plant were VK-1, PQ-9 followed by UQ-8. These results suggests that nutrients, seasons and material of sedimentation basin have notable influence on composition of attached algae and microbial community structure in water and wastewater treatment plants.

• 한국환경과학회지
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• 제8권5호
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• pp.611-616
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• 1999

The diagnostic software for the wastewater treatment plant using activated-sluge process is developed in order to increase the efficiency of management of the wastewater treatment plant. This software is based on the expert system and the visualized user interface, including the diagnosis of quantitative and qualitative data. For the generalization of this software, the initialization of each unit process and updating the files can be possible.

• 한국환경과학회지
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• 제16권2호
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• pp.227-232
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• 2007

Water pollution in enclosed water bodies such as lake and river has become a serious problem over the world. Domestic wastewater is responsible for more than 60 % pollution load in public water area in Korea. Effluent of the treated domestic wastewater at low removal level is abundantly fed rivers and lakes and thus be an serious cause of lake pollution. Therefore, effective implement of domestic wastewater treatment in basin of lake and river must be prepared. The septic tank is one of the effective domestic wastewater treatment equipment and used in individual treatment for a unit of household, The purpose of septic tank as biological treatment system is simultaneously to remove BOD, T-N, T-P and reduce turbidity from influent. Accordingly, the appropriate control of functional microorganisms is important subject for the establishment of stability and economy of the biological treatment method. Especially, microanimals as a high-ranked microorganisms of food-chain are important, because microanimals control the other microorganisms especially various bacteria and effect on function of treatment. Therefore, it is necessary that functional predator like rotifers are attached in wastewater treatment process. In this study, the methods for attachment high density the rotifer to and improvement of transparency in the effluence by a dense rotifer was examined using laboratory scale biological treatment reactor simulated septic tank and real one.