• 상하수도학회지
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• 제38권1호
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• pp.1-15
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• 2024

Occurrence of process environment changes, such as influent load variances and process condition changes, can reduce treatment efficiency, increasing effluent water quality. In order to prevent exceeding effluent standards, it is necessary to manage effluent water quality based on process operation data including influent and process condition before exceeding occur. Accordingly, the development of the effluent water quality prediction system and the application of technology to wastewater treatment processes are getting attention. Therefore, in this study, through the multi-channel measuring instruments in the bio-reactor and smart multi-item water quality sensors (location in bio-reactor influent/effluent) were installed in The Seonam water recycling center #2 treatment plant series 3, it was collected water quality data centering around COD, T-N. Using the collected data, the artificial intelligence-based effluent quality prediction model was developed, and relative errors were compared with effluent TMS measurement data. Through relative error comparison, the applicability of the artificial intelligence-based effluent water quality prediction model in wastewater treatment process was reviewed.

• 한국해양공학회지
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• 제22권2호
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• pp.34-41
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• 2008

As a basic study for developing a forecasting/estimating system that predicts water quality changes when Deep Sea Water (DSW) drains to the ocean after using it, this study was carried out as follows: 1) numerical simulation of the present state at DSW developing region in the East sea using SWEM, 2) numerical prediction of water quality changes by effluent DSW, 3) analysis of influence degree 'With defined DEI (DSW effect index) at F station. On the whole, when DSW drained to the ocean, Chl-a, COD and water-temperature were decreased and DIN, DIP and DO were increased by effluent DSW, and Salinity was steady. According to analysis of influence degree, the influence degree of DIN was the highest and it was high in order of Chl-a, COD, Water-temperature, DO, DIP and Salinity. The influence degree classified by DSW effluent position was predicted that suiface outflow was lower than bottom outflow. Ad When DSW discharge increased 10 times, the influence degree increased about $5{\sim}14$ times.

• 한국농공학회지
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• 제44권5호
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• pp.96-105
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• 2002

As an useful water purification system for non-point source pollution in rural watersheds, interests in constructed wetlands are growing at home and abroad. It is well known that constructed wetlands are easily installed, no special managemental needs, and more flexible at fluctuating influent loads. They have a capacity for purification against nutrient materials such as phosphorus and nitrogen causing eutrophication of lentic water bodies. The Constructed Wetland Design Model (CWDM), developed through this study is consisted mainly of Database System, Runoff-discharge Prediction Submodel, Water Quality Prediction Submodel, and Area Assessment Submodel. The Database System includes data of watershed, discharge, water quality, pollution source, and design factors for the constructed wetland. It supplies data when predicting water quality and calculating the required areas of constructed wetlands. For the assessment of design flow, the GWLF (Generalized Watershed Loading Function) is used, and for water quality prediction in streams estimating influent pollutant load, Water Quality Prediction Submodel, that is a submodel of DSS-WQMRA model developed by previous works is amended. The calculation of the required areas of constructed wetlands is achieved using effluent target concentrations and area calculation equations that developed from the monitoring results in the United States. The CWDM is applied to Bokha watershed to appraise its application by assessing design flow and predicting water quality. Its application is performed through two calculations: one is to achieve each target effluent concentrations of BOD, SS, T-N and T-P, the other is to achieve overall target effluent concentrations. To prove the validity of the model, a comparison of unit removal rates between the calculated one from this study and the monitoring result from existing wetlands in Korea, Japan and United States was made. As a result, the CWDM could be very useful design tool for the constructed wetland in rural watersheds and for the non-point source pollution management.

• Environmental Engineering Research
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• 제19권1호
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• pp.31-36
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• 2014

In this study, the influence of the control and operational parameters within a sewage treatment plant were reviewed by performing multiple regression analysis on the effluent quality of the sewage treatment. The data used for this review are based on the actual data from a sewage treatment plant using the media process within the year 2012. The prediction models of chemical oxygen demand ($COD_{Mn}$) and total nitrogen (T-N) within the effluent of the 2nd settling tank based on the multiple regression analysis yielded the prediction accuracy measurements of 0.93 and 0.84, respectively; and it was concluded that the model was accurately predicting the variances of the actual observed values. If the data on the energy spent on each operating condition can be collected, then the operating parameter that conserves energy without violating the effluent quality standards of COD and T-N can be determined using the regression model and the standardized regression coefficients. These results can provide appropriate operation guidelines to conserve energy to the operators at sewage treatment plants that consume a lot of energy.

• 대한환경공학회지
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• 제34권5호
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• pp.312-315
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• 2012

본 연구는 Media공법을 적용하고 있는 하수처리장의 실데이터를 활용하여 다중회귀분석을 통해 유출수질을 예측하는 모형을 구현하였다. 다중회귀분석은 2011년 1년간 데이터를 사용하였으며, 변수선택법 적용, 이상치와 영향치 제거, 변수의 로그변환에 따른 CASE별 연구를 수행하였다. 다중회귀분석으로 구축된 예측 모형으로 예측정확도를 검토한 결과, 2차침전지 유출수 $COD_{Mn}$는 0.87 이상, T-N은 0.81 이상으로 검토되었으며, 구축된 다중회귀모형을 이용하여 유출수가 방류수질기준을 초과하지 않는 운전조건의 범위를 설정할 수 있을 것으로 판단된다. 결론적으로 설정된 운전조건 범위 안에서 수질측면과 에너지 비용측면으로 하수처리장 운영시 운전자에게 적절한 운전 가이드를 제공할 수 있을 것으로 판단된다.

• 제어로봇시스템학회논문지
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• 제14권11호
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• pp.1174-1179
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• 2008

Many modeling and calibration methods have been developed to analyze and design the biological wastewater treatment process. For the systematic use of activated sludge model (ASM) in a real treatment process, a most important step in this usage is a calibration which can find a key parameter set of ASM, which depends on the microorganism communities and the process conditions of the plants. In this paper, a standardized calibration protocol of the ASM model is developed. First, a weighted effluent quality index(WEQI) is suggested far a calibration protocol. Second, the most sensitive parameter set is determined by a sensitive analysis based on WEQI and then a parameter optimization method are used for a systematic calibration of key parameters. The proposed method is applied to a calibration problems of the single carbon removal process. The results of the sensitivity analysis and parameter estimation based on a WEQI shows a quite reasonable parameter set and precisely estimated parameters, which can improve the quality and the efficiency of the modeling and the prediction of ASM model. Moreover, it can be used for a calibration scheme of other biological processes, such as sequence batch reactor, anaerobic digestion process with a dedicated methodology.

• 제어로봇시스템학회논문지
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• 제15권5호
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• pp.555-561
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• 2009

The established mathematical modeling methods have limitation to know the hydraulic characteristics at the wastewater treatment plant which are complex and nonlinear systems. So, an artificial neural network (ANN) model based on hydraulic characteristics is applied for modeling wastewater quality of a full-scale wastewater treatment plant using DNR (Daewoo nutrient removal) process. ANN was trained using data which are influents (TSS, BOD, COD, TN, TP) and effluents (COD, TN, TP) components in a year, and predicted the effluent results based on the training. To raise the efficiency of prediction, inputs of ANN are added the influent and effluent information that are in yesterday and the day before yesterday. The results of training data tend to have high accuracy between real value and predicted value, but test data tend to have lower accuracy. However, the more hydraulic characteristics are considered, the results become more accuracy.

• 한국도시환경학회지
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• 제18권4호
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• pp.401-408
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• 2018

하수처리 공정모델링 소프트웨어인 EQPS(Effluent Quality Prediction System, Dynamita, France)를 적용하여 A하수처리시설 생물반응조 설계의 적합성을 분석하였다. A하수처리장은 친수용수 수준의 목표수질을 준수하기 위하여 이차침전지 유출수 설계농도를 총질소와 총인, 각 10 mg/L, 1.8 mg/L로 설정하여 설계하였다. 4-Stage BNR 공정인 반응조의 체류시간은 총 9.6시간으로 전무산소조 0.5, 혐기조 1.0, 무산소조 2.9, 호기조 5.2시간이었다. 동절기 공정모델링 결과 친수용수 수준의 목표수질을 만족하기 위하여 혐기조의 체류시간을 0.2시간 늘렸고 당초 설계조건이던 외부탄소원 비상시 주입을 상시적으로 주입해야 하는 것으로 조사되었다. 모델링 결과의 왜곡을 배제하기 위하여 소프트웨어 제조사가 제시한 one step nitrification denitrification 모델의 Default 계수를 사용하였다. 공정모델링은 대체적으로 최적의 상태를 제시하기 때문에 생물반응조 여유율을 고려하면 4-Stage BNR의 체류시간은 9.8시간보다 증가시켜야 한다. 하수처리장 설계단계에서 공정 모델링의 정확한 사용은 하수처리장 건설 후 처리성능과 효율의 안정성을 담보할 수 있는 방법이므로 설계단계에서 철저한 평가가 필요하다.

• 한국수산과학회지
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• 제12권3호
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• pp.175-179
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• 1979

대체로 활성슬럿지 공법에서 가장 큰 문제점은 처리후의 미생물의 분리, 슬럿지 반송, 잉여슬럿지의 소화이다. 반면에 생물학적 고정막을 이용한 RBC, 실수여과상, 고정층활성 슬럿지 공법들은 이와같은 문제가 해소된다. 최근 침전시설 및 농축조를 설치할 필요가 없느 반고정망 활성슬럿지 공법이 개발되었다. 이 공법은 최종 처분할 슬럿지량도 감소되며, 유출수의 수질도 양호하고 최대축척용량으로 유출수의 수질은 추정할 수 있으나, 반응조가 동적인 수리학적 양상의 결여 되어있었다. 따라서 본 연구에서는 반응조가 좀더 동적 수리학적 양상이 되도록 설계하여 운전하였으며 그 운전결과는 다음과 같다. REMSMAS 공법은 침전시설 및 농축시설없이도 양호한 유출수를 얻을 수 있었으며 슬럿지 부착능력도 RESMAS 공법이나 FAST 공법 보다 크게 나타났으며 최대축척용량에 도달되는 한계운전기일은 대략 유기물부하량에 비례하였다.

• 해양환경안전학회지
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• 제15권2호
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• pp.91-98
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• 2009

아산만 해역으로 방류수가 배출될 경우, 생태-유체역학모델을 이용하여 아산만 해역의 장기 수질변화를 예측하였다. 생태-유체역학 모델은 해수유동 시뮬레이션을 위한 다층모델과 수질시뮬레이션을 위한 생태계모델로 구성되어 있다. 생태-유체역학모델을 이용하여 아산만해역의 장기 수질을 예측한 결과, 5개 정점에서 화학적산소요구량, 용존무기질소 및 용존무기인의 농도분포는 현재 계산결과에서 6개월 동안 증가하였다. 수치실험 수행시간 1년에서 2년 사이에서는 화학적 산소요구랑, 용존무기질소, 용존무기인의 농도분포는 6개월 동안 증가한 농도분포가 차츰 감소하는 경향을 보였으며, 3년에서 10년 사이에서는 일정한 농도분포를 보였다. 화학적 산소요구량, 용존무기질소 및 용존무기인의 농도는 $11{\sim}67%$, $10{\sim}67%$ 및 0.57%의 범위로 증가하였다. 10년 동안의 수치 실험 결과 화학적산소요구량과 용존무기질소의 변화 폭이 크게 나타났으며 이는 하수처리장의 방류수 중 이 두 오염부하량이 많은 양을 차지하고 있기 때문이다. 아산만 연안해역에서 화학적산소요구량, 총질소, 총인의 농도는 해역수질환경기준 II등급으로 조사되었으나, 하수처리장의 방류수가 배출될 경우 사업지구 인근의 아산만 방조제 부근에서는 해역수질환경기준 III등급으로 나타났다.