• 한국물환경학회지
• /
• 제39권1호
• /
• pp.46-60
• /
• 2023

Climate change causes fluctuations in water quality in the aquatic environment, which can cause changes in water circulation patterns and severe adverse effects on aquatic ecosystems in the future. Therefore, research is needed to predict and respond to water quality changes caused by climate change in advance. In this study, we tried to predict the dissolved oxygen (DO), chlorophyll-a, and turbidity of the Paldang reservoir for about two weeks using long short-term memory (LSTM) and gated recurrent units (GRU), which are deep learning algorithms based on recurrent neural networks. The model was built based on real-time water quality data and meteorological data. The observation period was set from July to September in the summer of 2021 (Period 1) and from March to May in the spring of 2022 (Period 2). We tried to select an algorithm with optimal predictive power for each water quality parameter. In addition, to improve the predictive power of the model, an important variable extraction technique using random forest was used to select only the important variables as input variables. In both Periods 1 and 2, the predictive power after extracting important variables was further improved. Except for DO in Period 2, GRU was selected as the best model in all water quality parameters. This methodology can be useful for preventive water quality management by identifying the variability of water quality in advance and predicting water quality in a short period.

• 산업기술연구
• /
• 제32권A호
• /
• pp.57-64
• /
• 2012

In order to examine the tailorability of advanced sewage treatment of a separated sewer pipe, we observed the quality of leaked water in a reactor. A2C affiliation and MBR affiliation decreased by over 78% in cases of BOD, COD, and SS. SBR affiliation decreased by 79.1% in a case of T-N. Overall, the efficiency of T-N on the above affiliations was low. SS had the high efficiency in MBR affiliation. In the end, examination of water quality improvement showed that the quality was improved from 20% to 90%; hence, it is expected that this treatment can protect the water resources of the Hongcheon River and makes it easier to use the water of the river.

• 상하수도학회지
• /
• 제11권1호
• /
• pp.99-108
• /
• 1997

This study examined the feasbility of upgrading D waste water treatment plant which treats incoming wastewater by primary sedimentation only. By adding 20-40 ppm of Hi-PAX into the outlet of the aerated grit chamber, BOD and SS removal efficiences were improved from 29% and 36% to 53 % and 73%,respectively. However, chemically enhanced primary treatment failed to meet the upcoming wastewater quality standard(BOD and SS <20 mg/l) consistently. This was suspected to result from the deteriorated plant return stream. The wastewater treatment by chemical treatment should have increased the amount of the sludge to be removed as the sludge production was increased. Chemically enhanced primary treatment is anticipated to consistently produce effluent of the 1996 standards quality by adjusting the amount of the sludge to be removed. Besides BOD and SS removal, chemically enhanced primary treatment resulted in the improved T-P removal from 30% to 64-74%. However, such benefit was not observed in T-N removal. Improved T-P removal will be expected to help control water pollution in Masan bay.

• 한국물환경학회지
• /
• 제25권6호
• /
• pp.902-909
• /
• 2009

With various reservoirs, dams and reduction of water velocity in downstream, rivers in Korea often have characteristics of accumulation of pollutants. Therefore, the main focus of water quality modeling in Korea needs to be shifted from DO to algae and organic matter. Moreover the structures of water quality models should be modified to have capability of simulating BOD which is a key factor of total water pollution load management in Korea as laboratory experiment BOD (Bottle $BOD_5$). In the SWAT model which is one of the widely used water quality models in Korea, the channel water quality module is using main algorithm of the QUAL2E model which has limitations in simulating algae, organic matter and Bottle BOD5 etc. To overcome this hindrance, in this study, the improved channel water quality module of the SWAT model (Q-SWAT) was proposed by linking the algorithms of the QUAL-NIER model which was developed based on the QUAL2E model to the SWAT model. The algorithms estimating the increase of internal organic matter by fractionization algal metabolism process and calculating Bottle $BOD_5$ were added and the results of proposed model were compared to those of the original SWAT model. The results of comparison test are showing that more accurate BOD values can be obtained with the Q-SWAT model and it is anticipated that the Q-SWAT model can be used as an effective tool of decision support through the water quality simulation and long term pollution source analysis.

• 한국수자원학회논문집
• /
• 제36권5호
• /
• pp.863-878
• /
• 2003

본 연구에서는 하천의 유지용수를 확보하기 위하여 하수처리장에서 처리하여 방류하는 하수처리수를 활용하기 위한 방안을 검토하고 이를 하천유지용수로 직접 활용하기 위하여 역순환시스템의 활용을 검토하였다. 역순환시스템은 하천 하류에 위치한 하수처리장으로부터 방류되는 하수처리수를 펌핑하여 하천상류부로 이송함으로써 하천에 부족한 유지유량을 확보하는 방법으로 여러 가지 형태의 이송방안을 조합하여 하천의 특성에 맞는 최적의 시스템을 구성하고 간단한 수처리를 적용함으로서 하수처리수의 수질을 추가적으로 개선할 수 있는 특징이 있다. 또한 이송된 하수처리수를 하천에 유입시키는 방안들은 시각적으로 친수적인 경관을 제공하고 폭기 등에 의한 수질개선효과를 얻을 수 있다. 이러한 하수처리수를 활용한 역순환시스템을 하천유지용수확보에 적용하기 위하여 국내 하수처리장의 처리수 활용실태 및 수질 상태 등을 검토하였고, 국내의 하수처리수 활용 사례를 조사하였으며 외국의 유사사례 조사를 통해 국내에 적용하기 위한 방안을 마련하고 실제 하천을 대상으로 역순환시스템의 적용방안을 제시하였다.

• Membrane and Water Treatment
• /
• 제10권5호
• /
• pp.339-352
• /
• 2019

Long term water quality change was analyzed to evaluate the effect of the Total Maximum Daily Load (TMDL) policy. A trend analysis was performed for biochemical oxygen demand (BOD) and total phosphorus (TP) concentrations data monitored at the outlets of the total 41 TMDL unit watersheds of the Nakdong River in the Republic of Korea. Because water quality data do not usually follow a normal distribution, a nonparametric statistical trend analysis method was used. The monthly mean values of BOD and TP for the period between 2004 and 2015 were analyzed by the seasonal Mann-Kendall test and the locally weighted scatterplot smoother (LOWESS). The TMDL policy effect on the water quality change of each unit watershed was analyzed together with the results of the trend analysis. From the seasonal Mann-Kendall test results, it was found that for BOD, 7.8 % of the 41 points showed downward trends, 26.8 % and the rest 65.9% showed upward and no trends. For TP, 51.2% showed no trends and the rest 48.8% showed downward trends. From the LOWESS analysis results, TP began to decrease in most of the unit watersheds from mid-2010s when intensive chemical treatment processes were introduced to existing wastewater treatment plants. Overall, for BOD, relatively more points were improved in the main stream compared to the points of the tributaries although overall trends were mostly no trend or upward. For TP, about half of the points were improved and the rest showed no trends.

• 한국습지학회지
• /
• 제19권2호
• /
• pp.240-245
• /
• 2017

본 연구에서는 생태계서비스 중 수질조절 서비스 가치 평가를 수행하기 위해 생태계서비스 수질조절 서비스의 물리량을 정량적으로 평가하였고 이를 이용하여 경제적 가치를 평가하는 방안을 마련하였다. 과거에 비해 수질이 개선되고, 어류 등 수생생물의 종과 수가 늘었더라도, 그 요인은 생태계의 수질조절 서비스와 수질개선를 위한 환경기초시설의 확충, 수질환경규제 등 복합적인 요인에 기인된다. 그 중 생태계 조절서비스 가치에 대해 정량적으로 산정할 수 있는 방법을 모색하는 것을 연구의 목적으로 설정하였다. 본 연구에서 생태계의 수질조절 서비스를 정량적 가치를 규명하기 위해 수질오염총량을 활용하는 방법에 대해 제안하였다. 이와 함께 생태계의 수질조절 서비스의 산정된 물리적 수질조절량에 처리단가를 곱함으로써 경제적 가치 평가 방안을 제시하였다. 마지막으로 개발된 평가기법을 이용하여 낙동강 수계에 BOD, T-P 항목에 대해서 생태계 수질가치를 평가하였다.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2002년도 학술발표회 발표논문집
• /
• pp.469-472
• /
• 2002

This study was conducted to show how to manage the water quality of Kyung-an river. The water quality and hydrologic data were obtained at the main river and branch streams in Marc $h{\sim}April$ 1998. First of all, we surveyed the contribution of branches for the pollution of water quality at Kyung-an river. It was in order of Kongiam(25.5%)>Yong-in Pollutant Treatment Complex (15.26%)^gt;Shin-won(13.99%)>Buen(11.86%)>Yangji(8.68%)>Yooun(7.43%)>Kwang-ju Pollution Treatment Complex(5.50%)>Osan(5.04%). The hydrological model using mass balance and BOD reduction formula suggested that if the quality of water Yoo-un and Shinn-won stream (branch streams of Kyung-an River) which is lowest in the basin is controlled adequately and outlet water from Yong-in pollutant treatment complex is adequately treated, the quality of Kyung-an river will be improved by 90% compared to current level.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2012년도 학술발표회
• /
• pp.772-777
• /
• 2012

In order to examine the tailorability of advanced sewage treatment of a separated sewer pipe, we observed the quality of leaked water in a reactor. A2C affiliation and MBR affiliation decreased by over 78% in cases of BOD, COD, and SS. SBR affiliation decreased by 79.1% in a case of T-N. Overall, the efficiency of T-N on the above affiliations was low. SS had the high efficiency in MBR affiliation. In the end, examination of water quality improvement showed that the quality was improved from 20% to 90%; hence, it is expected that this treatment can protect the water resources of the Hongcheon River and makes it easier to use the water of the river.

• 수산해양기술연구
• /
• 제26권4호
• /
• pp.341-352
• /
• 1990

The purpose of this research is to develop the design/control method that can be used for the improvement of harbour tranquility and water quality of fishing ports. For this end, firstly, the hydraulic environmental characteristics of fishing ports in the coastal waters of the Korean Peninsula are analysed and discussed combined with disasters of facilities and vessels in the ports. Secondly the problems of water quality control is pointed out considered with the improvement measures of harbour tranquility such as the methods of lengthen of main breakwaters and construction of wave absorbing structures. Finally, the control characteristics of composite functions of water quality and tranquility of fishing port are discussed and the improved control method si proposed using the experimental results for the various measures. The proposed measure is proved to be a applicable method to improve these two main functions on the design of fishing port.