• 상하수도학회지
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• 제11권3호
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• pp.87-95
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• 1997

A river water quality management model was made by Dynamic programming. This model optimizes the wastewater treatment cost of the application area, and computed water quality with it must meet the water quality standard. And this model takes into consideration tributary input, wastewater treatment plant effluent, withdrawls for several purposes. Modified Streeter-Phelps equation was used to calculate BOD and DO. Optimization problem was solved with particular exceedance probability flow, and the water quality of each point was calculated with the decided treatment efficiencies. At that time, the probability satisfying the water quality standard of constraints to the exceedance probability of the flow. The developed model was applied to the lower part of the Han-River. The reliability to meet the water quality standard is 70 % when 4 wastewater treatment plants of Seoul City are operated by activated sludge system at autumn of the year 2001. Treatment cost of this case is 121.288 billion won per year.

• 상하수도학회지
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• 제20권3호
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• pp.339-343
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• 2006

• 수도
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• 제23권5호통권80호
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• pp.54-59
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• 1996

• 한국물환경학회지
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• 제40권4호
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• pp.168-178
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• 2024

Wastewater treatment plants are constantly exposed to influent wastewater that is constantly changing. This poses a major challenge to the operation of the plants. It is crucial to have a rapid and accurate measurement of the influent concentrations of wastewater in order to maintain and optimize treatment performance, as well as to develop energy-saving strategies. While laboratory measurements provide the highest accuracy in determining influent water quality, they are inevitably time-consuming procedures. In order to cope with the ongoing disturbances from wastewater influent, absorption-based optical measuring instruments have been developed. These instruments can detect the influent water quality in a short amount of time, improving their practicality and reliability. However, when these optical measuring instruments malfunction, the accuracy of the measured values decreases, leading to unreasonable operation of the treatment plant. This paper proposes a method for detecting anomalies in optical water quality measurement devices. The Harmony Search algorithm is used to validate the measured water quality values and detect abnormalities such as contamination or physical anomalies in the measurement apparatus. To assess the performance of the developed algorithm in detecting anomalies, validation was conducted by installing it in a field-scale wastewater treatment plant. The results consistently showed that the developed fault detection method for optical water quality measurements equipment provided acceptable results for normal, temporary abnormal, and long-term abnormal conditions.

• 한국물환경학회지
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• 제37권1호
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• pp.20-31
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• 2021

In this study, an analysis of the characteristics of organic matter and nitrogenous oxygen demand (NOD) of 17 sewage effluent and wastewater treatments was conducted. High CODMn and carbonaceous biological oxygen demand (CBOD) concentrations were observed in the livestock treatment plants (LTP), wastewater treatment plants(WTP), and night soil treatment plants (NTP), but the highest NOD concentration and contribution rates of NOD to BOD5 were found in sewage treatment plants (STP). There was no significant difference in the CBOD/CODMn ratio for each of the six pollution source groups, but the LTPs, WTPs, and NTPs all showed relatively high CODMn concentrations in their effluent samples, indicating that they are facilities which discharge large amounts of refractory organic matter. The seasonal change of NOD in all facilities' effluent was found to be larger than the seasonal change of CBOD, and data results also revealed an elevation of NOD and NH3-N concentration from December to February, when the water temperature was low. There was no significant difference in NH3-N concentration in relation to pollution source group (p=0.08, one-way ANOVA), but the STP, which had a high NOD contribution rate to BOD5 of 48%, showed a high correlation between BOD5 and NOD (r2=0.95, p<0.0001). These results suggest that the effect of NOD on BOD5 is an important factor to be considered when analyzing STP effluent.

• 한국물환경학회지
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• 제40권1호
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• pp.36-46
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• 2024

Microplastics in water resources have been recognized as a serious problem. The discharge of microplastics from wastewater treatment plants is considered a major contributor to environmental pollution in water resources. However, a reliable analytical method for quantifying microplastics in wastewater treatment plants has not yet been established. This study proposes a reliable, quick, and easy analytical method for quantifying microplastics. For the removal of organic particles, preprocessing steps were applied including oxidation, sonication, washing, and sieving. Nile Red staining was used to visualize microplastics, and quantitative analysis was conducted using fluorescent imaging. The stained microplastics were ultimately quantified through image analysis software. Among the preprocessing steps, sonication and washing stages were particularly effective in efficiently removing interfering substances from wastewater, enhancing the accuracy of the microplastic analysis. Additionally, various solvents (methanol, acetone, and N-hexane) for the Nile Red staining solution were tested. When N-hexane was applied as the solvent, the quantity of stained microplastics was lower compared to methanol and acetone. This suggests that N-hexane has a greater potential of reducing false staining and counting of non-plastic particles. In summary, this research demonstrates a robust method for quantifying microplastics in wastewater treatment plants by employing effective preprocessing steps and optimizing the staining process with Nile Red and N-hexane.

• 상하수도학회지
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• 제26권3호
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• pp.399-408
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• 2012

The overall goal of this study was to characterize and quantify ammonia-oxidizing bacteria (AOB) in four different full-scale sequence batch reactor (SBR) wastewater treatment plants. Also, this study focused on assessing the occurrence of the alternative ammonia-oxidizing microbes such as anammox (anaerobic ammonia oxidation) bacteria (AMX) and ammonia-oxidizing archaea (AOA) in these systems. Based on total AOB numbers and the estimated cell density in the mixed liquor samples, AOB constituted 0.3 - 1.8% of the total bacterial population in the four WWTPs. Based on clone library, Nitrosomonas ureae-like AOB were dominant in plant A and B, while plant C and D had Nitrosomonas nitrosa-like AOB as major AOB group. The four different AMX primer sets targeting AMX 16S rRNA gene produced PCR amplicons distantly related to Chlamydia and Planctomycetales group bacteria. However, it was not clear these groups of bacteria perform anammox reaction in the SBR plants. Also, molecular evidence of AOA was found in one of the SBR plants, with a sequence located in the deep branch of the sediment creanarchaeota group.

• Membrane and Water Treatment
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• 제1권4호
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• pp.273-282
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• 2010

Treatment and reuse of industrial wastewater is becoming a major goal due to water scarcity. This may be carried out using membrane separation technology in general and reverse osmosis (RO) in particular. In the current study, polyamide (FT-30) membrane was employed for treatment of wastewater obtained from Faraman industrial zone based in Kermanshah (Iran). The effects of operating conditions such as transmembrane pressure, cross flow velocity, temperature and time on water flux and rejection of impurities including COD by the membrane were elucidated. The aim was an improvement in membrane performance. The results indicate that most of the chemical substances are removed from the wastewater. In particular COD removal was increased from 64 to around 100% as temperature increased from 15 to $45^{\circ}C$. The complete COD removal was obtained at transmembrane pressure of 20 bars and cross flow velocity of 1.5 m/s. The treated wastewater may be reused for various applications including makeup water for cooling towers.

• 상하수도학회지
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• 제34권5호
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• pp.357-371
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• 2020

Microplastics have become a rising issue in due to its detection in oceans, rivers, and tap water. Although a large number of studies have been conducted on the detection and quantification in various water bodies, the number of research conducted on the removal and treatment of microplastics are still comparatively low. In the current research, the inflow and removal of microplastics were investigated for various drinking water treatment plants around the world. Addition to the investigation of filed research, a survey was also conducted on the current research trend on microplastic removal for different treatment processes in the drinking water treatment plants. This includes the researches conducted on coagulation/flocculation, sedimentation, dissolved air flotation, sand filtration and disinfection processes. The survey indicated mechanisms of microplastic removal in each process followed by the removal characteristics under various conditions. Limitations of current researches were also mentioned, regarding the gap between the laboratory experimental conditions and field conditions of drinking water treatment plants. We hope that the current review will aid in the understanding of current research needs in the field of microplastic removal in drinking water treatment.

• 한국수자원학회논문집
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• 제52권11호
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• pp.947-950
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• 2019

이 논문의 주요 특징은 초기강우 유입 시 일차 침전지 처리효율을 개선하기 위한 운전제어 전략을 제공하는 것이다. 최근 IoT 기술과 센싱 기술이 발전함에 따라 하수처리시설 운전제어를 위한 기반이 개선되고 있으며, 온라인 측정결과를 활용한 일차침전지 처리효율 개선에 따라 미처리 하수의 하천 유출을 최소화하고, 하수처리시설 운영효율 개선에기여할 수 있다.