• 한국물환경학회지
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• 제24권6호
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• pp.641-650
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• 2008

This paper reviews the infrastructure of the water supply and sewerage system in North Korea. North Korean has similar legal protection to preserve water environment that can be seen in Republic of Korea, but North Korean regulations seemed lack of detailed measures. The critical pollution problems of rivers and lakes in the northern part of peninsula is mainly due to the lack of sewage collection system and poor treatment works. It has been estimated that less than 20% of sewers are connected to the wastewater treatment plants. Although the availability of water resources seemed sufficient, North Koreans suffer the lack of the drinking water supply which needs an urgent attention. Based on the analysis, it has been suggested that the reconstruction of North Korean water and sewage infrastructure needs at least 17.5 trillion Korean Won.

• 상하수도학회지
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• 제29권4호
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• pp.447-457
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• 2015

Water cycle within the human civilization has become important with urbanization. To date, water cycle in the eco-system has been the focus in identifying the degree of water cycle in cities, but in practicality, water cycle within the human civilization system is taking on an increasing importance. While in recent years plans to reuse water have been implemented to restore water cycle in cities, the effect that such reuse has on the entire water cycle system has not been analyzed. The analysis on the effect that water reuse has on urban areas needs to be go beyond measuring the cost-savings and look at the changes brought about in the entire city's water cycle system. This study uses a SWAT model and water balance analysis to review the effects that water reuse has on changes occurring in the urban water cycle system by linking the water cycle within the eco-system with that within the human civilization system. The SWAT model to calculate the components of water cycle in the human civilization system showed that similar to measured data, the daily changes and accumulative data can be simulated. When the amount of water reuse increases in urban areas, the surface outflow, amount of sewer discharge and the discharged amount from sewage treatment plants decrease, leading to a change in water cycle within our human civilization system. The determinant coefficients for reduced surface outflow amount and reduced sewer discharge were 0.9164 and 0.9892, respectively, while the determinant coefficient for reduced discharge of sewage treatment plants was 0.9988. This indicates that with an increase in water reuse, surface flow, sewage and discharge from sewage treatment plants all saw a linear reduction.

• 한국습지학회지
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• 제22권4호
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• pp.321-327
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• 2020

산업발전과 인구증가, 생활수준의 향상으로 하·폐수 발생량 및 하수처리장 연계처리수가 매년증가 하고 있다. 연계처리수는 저유량 고농도의 특징을 가지고 있다. 따라서 하수처리장 운영에 큰 영향을 미치고 연계처리수를 처리하기 위해 많은 비용도 사용되는 것으로 나타났다. 본 연구에서는 연계처리수의 유입 유량을 개별 반응조로 전량 유입시킬 경우 방류수 수질이 적게 상승한 시나리오를 도출했고, 모델링 결과 유입하수, 무산소조에 유입시킬 경우 방류수 수질이 가장 적게 상승하는 것을 확인할 수 있었다. 이와 같은 결과를 바탕으로 연계처리수의 유입 유량을 유입하수와 무산소조로 분배하여 유입시킬 경우에 대하여 분배 비율에 대한 다양한 시나리오를 생성했다. 다양한 시나리오를 통해 모델링을 진행한 결과 유입하수(80%), 무산소조(20%)의 비율로 연계처리수의 유입유량을 분배 유입 시킬 경우 TN, TP의 수질이 가장 적게 상승하는 것으로 나타났다.

• 상하수도학회지
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• 제27권5호
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• pp.603-610
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• 2013

According to industrialization, increased toxic chemicals discharge has been causing water pollution. Especially domestic sewage is a major source of water pollution. Sixty percent of the total wastewater discharged is domestic sewage. Self-purification capacity of rivers and streams is drastically reduced by the emission of domestic sewage, industrial wastewater and livestock wastewater. Although domestic sewage is managed by implementing standards and regulations, toxicity effect of domestic sewage to humans and the environment is not yet clearly understood. In this study, by using daphnia magna, the ecotoxicity of domestic swage was assessed. Cl, Cu, Pb, COD, T-N, DO, pH and residual chlorine were investigated as background concentrations. The experiments were conducted with water samples obtained from three local sewage treatment plants. The experiment results indicated that higher level of toxicity corresponds to the higher pollution concentrations. The higher level of combinations of background concentrations such as heavy metals leads to the worse ecotoxicity. Especially, the Cu concentration affects the TU value.

• 한국해안해양공학회지
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• 제19권4호
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• pp.385-398
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• 2007

주문진항에서 2002년부터 2005년까지 월별로 관측한 일반 수질항목의 정점별, 계절별 변화 양상을 분석하였다. 분석항목은 수온, 염도, pH, SS, DO 항목이다. 일반수질항목의 상층·하층 변화는 뚜렷한 차이를 보이지 않는 것으로 파악되었다. 반면, 계절별 농도변화는 수온 및 DO 농도는 뚜렷한 변화양상을 보였으나, SS 항목 등은 불규칙한 양상을 보이고 있는 것으로 파악되었다. 또한, 지점별, 월별 자료를 영역별, 연도별로 평균하여 해수교환시설 및 하수종말처리시설의 수질개선효과를 정량적으로 분석하였다. 분석 결과, SS농도변화는 하수종말 처리시설 가동에 의한 영향이 매우 미미하게 반영되었으며, 해수교환시설에 의한 영향은 영역 1, 2 각각 26%, 16% 정도의 명확한 농도저감효과를 보이고 있는 것으로 파악되었다. 한편, DO 농도는 하수종말 처리시설 가동 후, 주문진항 내부영역에서 10% 내외로 농도가 저하되는 효과를 보였으나, 해수교환시설 건설 후에는 오히려 10% 내외 증가되는 양상을 보이고, 2005년도 DO 농도는 2002년도에 비하여 변화가 없는 것으로 파악되어 10% 내외의 DO 농도변화는 하수처리장 및 해수순환시설 설치효과로 파악하는 것보다는 자연적인 연변화 범위로 판단하는 것이 적절할 것으로 사료된다.

• 상하수도학회지
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• 제18권1호
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• pp.59-65
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• 2004

The change of the microbial community structure in excess sludge of different sewage treatment plants by ozone treatment was investigated by quinone profiles. The resulting ozone dosage ranged from 0.1 to $0.4gO_3/gTS$. In terms of overall sludge reduction, more than 50% reduction of the total sludge mass could be achieved by ozone treatment at $0.4gO_3/gTS$. Quinone concentration and type in sludge of different treatment plants were remarkably decreases with increasing ozone dose. Ubiquinones(UQs)-8, -10 and MK-8 were still remained in the ozonized sludge at $0.4gO_3/gTS$. The results of this study showed that the remaining microorganisms belong to UQs-8, -10 and MK-8 were difficult to destruct cell membrane or wall by ozonation. Fecal Streptococci and Salmonella were not detected at ozone dose of $0.2gO_3/gTS$, but Fecal Coliform was not detected at ozone dose of $0.4gO_3/gTS$.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.922-927
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• 1991

This study is aimed to investigate a design problem of the fuzzy logic controller for the activated sludge process(ASP) in sewage treatment. The modeling technique proposed by Sugeno is used to express the ASP effectively and identification of a fuzzy model of the ASP is carried out utilizing actual operational data obtained from a metropolitan sewage plants. The model-based fuzzy controller is designed by rules generated from the identified ASP fuzzy model. Feasibility of the designed controller is tested through computer simulations.

• 한국환경보건학회지
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• 제36권2호
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• pp.141-147
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• 2010

Indicator bacteria of fecal pollution were enumerated and compared by various detection methods for influent and final effluent of a sewage treatment plant. Total coliforms were enumerated by four methods including most probable numbers, chromogenic enzyme substrate test, membrane filtration, and plate counts and were about $10^4$ for influent and $10^2{\sim}10^3\;CFU/ml$ for final effluent. Fecal coliforms ranged between $10^3$ and $10^4$ for influent and $10^2\;CFU/ml$ for effluent by chromogenic enzyme substrate test and membrane filtration. Fecal streptococci counts were 1-log less than fecal coliforms counts, $10^2{\sim}10^3$ for influent and $10^1\;CFU/ml$ for effluent. Total coliforms numbers by plate count both in influent and in effluent showed 1-log higher than by the other three methods. Statistical analysis revealed that numbers of total coliforms by plate count in final effluent had the highest average of correlation (r=0.778, p<0.01) compared with those by the other three methods. In addition, total coliforms numbers by plate count showed most significant correlation (r=0.835, p<0.01) with those by chromogenic test which is well-known as its highest recovery efficiency. These results suggest that the plate count would be the optimum detection method for total coliforms in wastewater treatment plants which are the only microbiological standard of final effluent from wastewater treatment plants in the Republic of Korea, considering economic aspects and difficulties in laboratories.

• 유기물자원화
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• 제16권2호
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• pp.81-87
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• 2008

본 연구에서는 버려지는 연탄재를 하수처리에 이용하여 그 처리효율 및 활용성 등을 조사하였다. 본 연탄재 공법에 의해 처리된 처리수의 $BOD_5$, CODcr, SS 등은 각각 1.1 (mg/L), 9.5 (mg/L), 3.8(mg/L)를 나타내며 원수와 비교하여 99%, 92.7%, 96.3%의 처리효율을 보여주었다. 본 연탄재공법에 의한 처리수의 총 세균 및 대장균에 대한 제거효율은 각각 평균 9 (cfu/ml) 및 1.2 (cfu/ml)로 나타나 기존의 하수처리장 방류수와 비교하여 괄목할만한 감소효과를 보여주었다. 한편, 1년 이상의 장기적 운전실험에서는 변함없는 높은 처리효율의 유지와 함께 계절별 처리효율의 변동폭이 매우 낮았으며, 슬러지발생이 차단되는 효과를 보여주었다. 본 연탄재공법은 연탄재를 재활용함은 물론, 높은 처리효율과 슬러지의 발생을 감소시킴으로써 환경친화적인 공법이라 할 수 있으며, 중소규모의 하수처리 및 처리수의 재활용에 매우 유용할 것으로 사료되는 바이다.

• 한국물환경학회지
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• 제20권3호
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• pp.275-280
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• 2004

This study was performed to investigate the disinfection efficiency and the formation characteristics of disinfection by-products(DBPs) by chlorination in the sewage effluent. The effluent was sampled from the sewage treatment plants operated in the activated sludge process and the advanced sewage process. The type of DBPs investigated were Trihalomethanes(THMs), Dichloroacetonitrile(DCAN), Chloral hydrate(CH), Dichloroacetic acid(DCAA), Trichloroacetic acid(TCAA). Major findings are as follows. First, the optimum injection concentration for chlorination in sewage effluent were found to be in the range $0.5{\sim}1.0mg\;cl_2/L$. Also, It was found that the chlorine dosage in the effluent of activated sludge process was higher than in the effluent of advanced sewage process. Second, the maximum formation concentration of THMs were $12.7{\mu}g/L$. The THMs formation reaction was finished in a short time of several seconds and chloroform was mainly formed. Also, it was found that the concentration of ammonium nitrogen is higher, the concentration of THMs is lower. Third, it was found that DCAA and TCAA were mainly formed as DBPs by disinfection.