• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.65-66
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• 2005

Anaerobic digestion is one of the well-known methods for biological treatment handling of concentrated organic matter such as swine $wastewater.^{1)} The anaerobic digestion can reduce organic loading but also hydrolyze non-biodegradable organic $matter.^{2)}$ The feces from the scrapper-type barn are usually collected to make compost and the urine is discarded with swine-slurry wastewater by ocean-dumping or treated by biological methods. The lagoon, aerobic digestion, anaerobic digestion, SBR, $A^{2}/O$, and UCT have been applied for treating swine $wastewater.^{3)} In this study, as a result of the analysis of swine wastewater, the total and soluble chemical oxygen demand was 130g/L and 60g/L, respectively. And the volatile fatty acid as chemical oxygen demand equivalent was 45g/L, which was 75% of soluble chemical oxygen demand. Before everything else, ammonia nitrogen concentration was 6.5 g/L. From biochemical acidogenic potential test, it was concluded that the enhanced acidification process to manage swine waste should be operated in the ammonia nitrogen concentration of less than 1.2 g/L. In the result of seeding ratio experiments with artificial $wastewater^{4)}, the lag period of acidogens was taken the long time because of the inhibition by the $ammonia^{5)}$, however no difference of period by the seeding ratio was not shown. The Haldane-based biokinetics were also evaluated using a method of fourth order Runge-Kutta $approximation.^{6,7)}$ The nonlinear least squares (NLLS) method with a 95% confidence interval was also used. The ranges of maximum microbial growth rate, ${/mu_{max}}$, and half saturation coefficient, $K_{s}$, for acidogenesis of various seeding ratio with artificial wastewater were 6.1 ~ 12.6 $d^{-1}$ and 45,000 ~ 53,500 mg glucose/L, respectively. Also, the methanogenic microbial yield coefficient, Y, and microbial decay rate coefficient, $k_{d}$, and inhibition substrate concentration, $K_{si}$, for the reactors were determined to be 0.32 ~ 0.465 ${/mu}g$/mg glucose; 0.42 ~ 1.01 $d^{-1}$ and 51,500 ~ 55,600 mg glucose/L, respectively.

• Environmental and Resource Economics Review
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• v.31 no.1
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• pp.85-112
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• 2022

This study analyzed the influence of domestic and Chinese factors on fine dust(PM10 & PM2.5) in Korea by using the panel quantile regression. Daily analysis was conducted for 11 regions in Korea. For domestic factors, electricity demand and traffic volume, and for Chinese factors, interaction term of Chinese three cities' fine dust and the domestic west wind are used. As a result, the influence of domestic factors was different when the domestic fine dust concentration was high and low. When the fine dust concentration was low, electricity demand had a positive effect only on PM2.5, and didn't affect PM10 in the national analysis. In regional analysis, the amount of electricity demand had a significant effect on fine dust and ultrafine dust only in the capital area and Chungcheong. Electricity demand was found to significantly increase both PM2.5 and PM10 when it was high. On the other hand, it was confirmed that the Chinese factor always had a significant effect regardless of the concentration of PM10 and PM2.5. Therefore, in order to solve the problem of high concentration of fine dust, in addition to international cooperation, the reduction of PM2.5 generated by domestic thermal power generation should also be strengthened compared to the present.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.6
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• pp.137-149
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• 2020

This study was carried out to analyze the monthly runoff concentration on non rainfall days in order to prepare basic data to compare the runoff concentration on rainfall days in 7 forest watersheds in the Republic of Korea. Forest stream water has been collected through 15 times of sampling in each watershed and analyzed based on the changes in concentration of Biochemical Oxygen Demand(BOD), Chemical Oxygen Demand(COD), Total Organic Carbon(TOC), Total Nitrogen(TN), and Total Phosphorus(TP). The average concentration was 0.8 mg/L for BOD, 1.4 mg/L for COD, 0.8 mg/L for TOC, 1.85 mg/L for TN and 0.002 mg/L for TP during non rainfall days. Coniferous forested watersheds showed higher value of TN and TP concentration. Concentrations of BOD and TP in early March (p<0.01) were affected by melt water flow input in spring season. Significant differences (p<0.01) in concentrations were observed in BOD and TOC, indicating seasonal rainfall and vegetation growth impacts on forest stream quality. Concentration of TN and TP showed significant positive correlation, and weak negative correlation was found in the concentration of BOD and TOC. It is expected that result of forest stream water on non rainfall days could be basic information in managing non-point source from forest watersheds.

• Journal of Environmental Science International
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• v.7 no.2
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• pp.203-208
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• 1998

A simple on-line measurement system consisting of a conventional peristaltic pump, a HPLC-type heater, and a flow-through spectrophotometer is introduced for the determination of chemical oxygen demand(CODI. The system was configured such that the reaction mixture in the highly concentrated surffuric acrid medium flowing through the PTFE reaction tubing was heated at 150℃ and the absorbance of dichromate was continuously moutored at 445 m. The same addation principle as in the standard procedure was employed akcept the use of CoSO4 as a new effective catalyst. To test the system, potassium hydrogen phthalate was selected as a COD standard material. With suitably optimized reaction condition, the applicable concentration range depends on the concentration of potassium dichromate in the oxidizing reagent. With 2.0×10-3 M and 5.0×10-4M dichromate, the linear dynamic range was observed up to 400 ppm and 100 ppm, respectively. The standards in the Unear ranges were shown to be completely oxidized, which was confirmed with sodium oxalate or Mohr's salt. In all cases, the typical reproduclbility for betweenruns was 2% or less. The proposed measurement system provides the valuable in- formation for the further development of automated analysis system based on the present standard procedure.

• Journal of Environmental Science International
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• v.2 no.4
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• pp.291-297
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• 1993

The COD values and chloride ion concentrations of the Taewha river flowing through Ulsan area were determined along the main stream and the relationships between CODs and chloride ion concentrations were described. The results showed that the middle-upper stream and downstream of the Taewha river were polluted deeply with municipal sewage and self-purification occured in the middle-downstream of the river. When domestic sewage is a main source of pollutants, and is especially the only source of chloride in the stream water, the ratio of COD/[$\textrm{Cl}^{-}$] will be utilizable as a measure of self-purification of the stream.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.3
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• pp.10-18
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• 1999

The influence of simple electrolyte or anionic trashes on cationic starch adsorption was examined using deinked pulp and bleached thermomechniical pulp. Adsorbed amounts of cationic starches increased slightly , then decreased abruptly as the concentration of simple electrolyte increased. This phenomenon was discussed based on the compression of electrical double layer and conformation change of starch molecules. Also, the effect of the type of simple electrolytes on starch adsorption was examined and discussed. Addition of sodium slilicate increased starch adsorption since it increased surface charge density of fibers. On the other hand, addition of kraft lignin decreased cationic demand of the pulp slurries and adsorbed amounts of cationic starches. Nonionic surfactant did not show any significant effect on the cationic demand of pulp slurries. When simple electrolytes were added to the stock , grater adsorption or cationic starches was obtained with starches of lower degree of substitution . On t도 other hand, amount of adsorbed starches decreased for lower DS starches when the concentration of anionic trashes increased.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.97.1-97
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• 2001

One of the main problems to constitute control method on biologically oriented wastewater purification processes, e.g. activated sludge process, sequential batch reactor, rotating bio-disk contactor, etc. is that it is hard to control the target component directly. For instance, while biochemical oxygen demand, suspended solids, and chemical oxygen demand are the key components to check the process performance, one may not control them directly since they are the results of microbial activities related to numerous physiochemical factors. Therefore controllers for bioprocess should be designed to make favorable condition for microorganisms´ living, e.g. dissolved oxygen level favorable, mixed liquor suspended solids concentration suitable ...

• Journal of Industrial Technology
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• v.27 no.B
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• pp.83-89
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• 2007

We studied runoff characteristics of combined sewer overflows in a city while it was raining. The event mean concentration (EMC) of biochemical oxygen demand (BOD), chemical oxygen demand ($COD_{Cr}$), suspended solids (SS), total nitrogen (TN), and total phosphorus (TP) in one of the combined sewer sites in Chuncheon was 63.5-211.6 mg/L, 114.9-523.8 mg/L, 70.3-436.4 mg/L, 6.4-33.0 mg/L, and 1.09-6.81 mg/L, respectively. In another combined sewer, the EMC of BOD, COD, SS, TN, and TP was 42.1-131.4 mg/L, 107.7-256.5 mg/L, 33.7-221.1 mg/L, 7.9-26.4 mg/L, and 1.16-3.91 mg/L, respectively. The ratio of the cumulative pollutant mass and the cumulative discharged volume determined using all parameters (BOD, $COD_{Cr}$, SS, TN, and TP) was over 1.0, which shows the first flush effect. Relationships between flow and loadings of BOD, $COD_{Cr}$, SS, TN, and TP were 0.90, 0.89, 0.88, 0.89, 0.92, respectively. Although the size of two areas was almost same, pollutant concentration and loading were different because of the amount of rainfall, rainfall intensity and basin area.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.445-452
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• 2007

This study was carried out to examine effect of post-chlorine dosage reduction by ozonation and GAC process in the field plant for 3years in the "G" water purification plant in Seoul. And it is to compare GAC with BAC process in removal effects of TOC, THMs, THMFP, $UV_{254}$. As a result, chlorine dosage of ozonation and GAC(=BAC) is less demand than GAC. Seasonal reduction of chlorine demand is from about 37% to 59% with BAC, and from 24 to 46% with GAC. Higher reduction in BAC could be achieved. The efficiency of chlorine demand reduction with ozonation was depending on the organic carbon removal. $UV_{254}$ concentration is less about 0.13~0.74L/mg.m in BAC than GAC. Therefore, the combination of ozonation and GAC was more effective in reducing post-chlorine than the single GAC. TOC was also monitored, and results show that a linear relationship between TOC and chlorine demand is appropriate under each treatment process. It means that removal of organic matter(TOC) from finished water is necessary to reduce post-chlorine dosage in clear well and to minimize order of chlorine in distribution systems.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.170-170
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• 2023

Providing safe and readily available water is vital to maintain public health. One of the most prevalent methods to prevent the spread of waterborne diseases is applying chlorine injection to the treated water before distribution. During the water transmission and distribution, the chlorine will experience a reduction, which can imply potential risks for human health if it falls below the minimum threshold. The ability to determine the appropriate initial intensity of chlorine at the source would be significant to prevent such problems. This study proposes two methods that integrate hydraulic and water quality modeling to determine the suitable intensity of chlorine to be injected into the source water to maintain the minimum chlorine concentration (e.g., 0.2 mg/l) at each demand node. The water quality modeling employs the first-order decay to estimate the rate of chlorine reduction in the water. The first method utilizes a backtracking algorithm to trace the path of water from the demand node to the source during each time step, which helps to accurately determine the travel time through each pipe and node and facilitate the computation of time-dependent chlorine decay in the water delivery process. However, as a backtracking algorithm is computationally intensive, this study also explores an alternative approach using a water age. This approach estimates the elapsed time of water delivery from the source to the demand node and calculate the time-dependent reduction of chlorine in the water. Finally, this study compares the outcomes of two approaches and determines the suitable and effective method for calculating the chlorine intensity at the source to maintain the minimum chlorine level at demand nodes.