• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.2
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• pp.89-97
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• 2007

In this study, thermalpretreatment was used to solubilize organic matter contained in sewage sludge before acid fermentation. By thermal pretreatment, solubilization of particulate CODcr, carbohydrate and protein increased. By thermal treatment at $120^{\circ}C$ for 30 minutes, CODcr solubilization efficiency of the primary sludge reached 8.3%. Meanwhile, for the secondary sludge, CODcr solubilization efficiency reached 16.5% because of high solubilization ratio of protein under the same pretreatment conditon. The results of anaerobic biodegradability test showed that both VFAs conversion ratio and hydrolysis rate of organic compounds in sewage sludge were improved by thermal pretreatment. Meanwhile, the optimum thermal pretreatment condition was varied with composition of organic compounds in sludge. In this study, the optimun thermal pretreatment condition of the primary sludge, containing high concentration of carbohydrate, was $80^{\circ}C$ for 30 minutes. Meanwhile, for the secondary sludge, mainly composed of protein, the sludge treated at $120^{\circ}C$ for 30 minutes showed the effective organic removal and VFAs production.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.401-408
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• 2018

EQPS (Effluent Quality Prediction System, Dynamita, France) was applied to analyze the appropriateness of the design of a bioreactor in A sewage treatment plant. A sewage treatment plant was designed by setting the design concentration of the secondary clarifier effluent to total nitrogen and total phosphorus, 10 mg/L and 1.8 mg/L, respectively, in order to comply with the target water quality at the level of the hydrophilic water. The retention time of the 4-stage BNR reactor was 9.6 hours, which was 0.5 for the pre-anoxic tank, 1.0 for the anaerobic tank, 2.9 for the anoxic tank, and 5.2 hours for the aerobic tank. As a result of the modeling of the winter season, the retention time of the anaerobic tank was increased by 0.2 hours in order to satisfy the target water quality of the hydrophilic water level. The default coefficients of the one step nitrification denitrification model proposed by the software manufacturer were used to exclude distortion of the modeling results. Since the process modeling generally presents optimal conditions, the retention time of the 4-stage BNR should be increased to 9.8 hours considering the bioreactor margin. The accurate use of process modeling in the design stage of the sewage treatment plant is a way to ensure the stability of the treatment performance and efficiency after construction of the sewage treatment plant.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.230-236
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• 2023

The sewage system was continuously distributed as a concept of public service and protection for water system such as wet-land, resulting in deterioration of the management of sewage management institutions. Accordingly, under the leadership of the central government, various sewage policies are being promoted to streamline the management of sewage management institutions. The main points were related to costs, and typical characteristics include wastewater cost and wastewater discharger cost. In this research, the current status and characteristics of the wastewater discharger cost of 71 local governments in Korea were analyzed. As a result, 41 places (57%) were found to be less than 1,000,000 won/m³ to 2,000,000 won/m³, with an average was 1,990,653 won/m³ (median was 1,918,000 won/m³). In addition, the rate of wastewater discharger cost was increased when the wastewater discharger cost was higher stage. The influential parameters of local governments, which were relatively correlated with the wastewater discharger cost, were analyzed as the rate of recovering wastewater cost and financial independence rate. The results of this research could be used as basic data for wastewater discharger cost, and future researches are needed on how to calculate the appropriate level of wastewater discharger cost.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.3
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• pp.9-14
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• 2009

Flow and pollution load were monitored at 2 combined sewer outlets (C-1 and C-2) of urban watersheds during dry weather from September, 2004 to April, 2006 for 20 months. The objectives were to investigate the diurnal variation of flow and pollutant load and to find the proper sampling time that could measure representative flow and pollutant load. Pollution load closed to the average daily load at C-1 could be measured at 00:00 hour and by the mean of 15:00 and 18:00 hour measures, and 15:00 and 21:00 hour measures, respectively. In addition at C-2, it was 21:00 hour and the mean of 15:00 and 18:00 hour measures. This study concluded that arbitrary sampling of flow and water quality could cause large errors in the estimation of urban pollution load and recommended that urban combined sewers should be monitored when flow and water quality showed daily average and concentration.

• Journal of Korean Society of societal Security
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• v.4 no.1
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• pp.57-65
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• 2011

Studying the operation of urban control plan and control program of urban plan facilities to present development direction of urban plan in the future by performing multi-variate analysis, the research acquired the following conclusion. It is required to institutionally activate the inhabitants' participation by reflecting spontaneous participation and opinion of inhabitants to adminstration so that the effect of business can be maximized in the stage of establishing urban control plan. Furthermore, the participation of role dividing type is necessary to adjust and connect the interest of expert that has experience in practical business of overall urban plan, inhabitant and self-governing body. It is required to reduce the service supplied by government so as to enhance policy of plan-first and development last for facilities with high importance and utility such as road, park and water supply/sewage, etc as well as to seek control program that expands the participation of private sector for administration for which private service is possible.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.2
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• pp.181-195
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• 2000

The effect of the intercepting ratios on the water quality improvement was simulated by using Finite Segment Method in a urban river where intercepting sewer under the ground and constructing sewage treatment plant are now being proceeded. To simulate variations of the water quality caused by river flows, rating curve at each gaging station was derived from measurements. Water quality data were from the exiting observations at each key stations from 1990 to 1998, for 1999 and 2000 data we measured in creek and drainage ditch in addition to observation stations. It revealed that increasing the intercepting ratios improved the water quality.

• Journal of Urban Science
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• v.8 no.2
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• pp.19-23
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• 2019

With the continuous progress of modern science and technology and the rapid development of economy, with the continuous development of society, the treatment of industrial and domestic sewage has become a hot concern. Toxic substances and non-degradable pollutants in wastewater also have a great impact on the environment. This paper mainly expounds the current environmental situation and the adsorption mechanism of activated carbon. And the application and development of activated carbon adsorption in wastewater.

• Journal of Urban Science
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• v.8 no.2
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• pp.1-5
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• 2019

China is the great powers of use and production of antibiotics.The current process of sewage treatment plants can not effectively remove antibiotics in water. Chinese scholars have detected different kinds of antibiotics in major waters of the country, which have potential harm to human body. Among all kinds of antibiotic treatment technologies, adsorption removal technology has the advantages of simple operation, low cost and high removal efficiency. It is a widely concerned antibiotic removal technology. However, at present, few materials have been put into practical application, and more materials with low cost and high efficiency need to be found. Different adsorptive materials have different adsorptivity to different antibiotics. For different antibiotics, different adsorptive materials can be integrated in the future, and the theory can be extended to application.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.2
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• pp.1-14
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• 2014

The purpose of this study is to identify the efficiency of LID technologies for controlling non-point source pollution from urban areas. The recent technical responses to managing water resource and urban areas according to the influence of climate change is an important national policy, along with green growth. Through various reference studies reasonable ways to consider a wholistic plan on urban-eco-friendly river management, the Low Impact Development (LID) as the adequate river management method is being undertaken in foreign countries to technically apply to urban plans. However, the LID is at the initial stage in Korea, with no specific studies implemented. Thus, this study explored whether LID technologies can be efficient measures to control non-point source pollution on the cost side. Ulsan's Namgu and Bukgu have been chosen as case studies that illustrate the efficiency of the LID technologies. On investigation, if LID technologies are designed properly, the efficiency of them is expected to higher than that of sewage treatment plant.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.308-315
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• 2006

Since sewage characteristics are the most important factors that can affect the biological reactions in wastewater treatment plants, a detailed understanding on the characteristics and on-line measurement techniques of the influent sewage would play an important role in determining the appropriate control strategies. In this study, samples were taken at two hour intervals during 51 days from $1^{st}$ October to $21^{st}$ November 2005 from the influent gate of sewage treatment plant. Then the characteristics of sewage were investigated. It was found that the daily values of flow rate and concentrations of sewage components showed a defined profile. The highest and lowest peak values were observed during $11:00{\sim}13:00$ hours and $05:00{\sim}07:00$ hours, respectively. Also, it was shown that the concentrations of sewage components were strongly correlated with the absorbance measured at 300 nm of UV. Therefore, the objective of the paper is to develop on-line estimation technique of the concentration of each component in the sewage using accumulated profiles of sewage, absorbance, and flow rate which can be measured in real time. As a first step, regression analysis was performed using the absorbance and component concentration data. Then a neural network trained with the input of influent flow rate, absorbance, and inflow duration was used. Both methods showed remarkable accuracy in predicting the resulting concentrations of the individual components of the sewage. In case of using the neural network, the predicted value md of the measurement were 19.3 and 14.4 for TSS, 26.7 and 25.1 for TCOD, 5.4 and 4.1 for TN, and for TP, 0.45 to 0.39, respectively.