• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.178-184
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• 2012

BOD decay rate is a key parameter of BOD-DO models in streams and lakes. In the calibration of water quality modeling appropriate range of coefficient is required for guidance of parameter selection. In this study BOD decay rate was measured at 48 stream sites and 10 reservoir sites in 8 different river systems. The decay rate ranged from 0.09 to 0.25 $day^{-1}$ with a mean of 0.16 $day^{-1}$. Among river systems the decay rates showed significantly different ranges, with the Han River system showing higher values than other river systems. In comparing different types of water bodies, the decay rate was slightly higher in tributaries than in reservoirs and mainstreams. Our results can provide guidance to the selection of proper coefficient for various water bodies in the calibration of water quality models.

• Journal of environmental and Sanitary engineering
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• v.15 no.2
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• pp.49-57
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• 2000

The objective of this study is to find solid waste decomposition in landfill without leachate discharge. This study was observed variation of landfill gas production rate and leachate for stabilization assessment, and using four sets of lysimeter as experimental apparatus. Soild waste decomposition was accelerated in without leachate discharge system by sufficient moisture for methane bacteria. And gas production rate was between 54.2ℓ/kg VS∼335.9ℓ/kg VS in each lysimeter. Generation time of methane gas was showed different in each lysimeter, but it was much faster than literature research. The time of stabilization phase were began as follows : L-1 400 day, L-2 350 day, L-3 170 day and L-4 70 day respectively. Decreasing times of BOD/COD ratio and C/N ratio were necessary more than literature research because organic matter was not discharge such as wash out.

• Analytical Science and Technology
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• v.23 no.1
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• pp.36-44
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• 2010

This study was performed to investigate the distribution and decomposition characteristics of organic matter in stream water and sewage effluent located in Gwangju. Average of dissolved organic carbon (DOC) to total organic carbon (TOC) ratio was approximately 73.9% in the Youngsan river system. The concentration of refractory dossolved carbon (RDOC) was 3.7 mg/L corresponding to 80.9% of the DOC. The ratio of recalcitrant organic carbon was relatively higher than that of biodegradable organic carbon in stream. Oxidation efficiencies in the stream were 45.0% for BOD, 63.0% for $COD_{Mn}$ and 106.5% for CODcr. In case of sewage effluent was 33.6%, 65.7% and 136.1% respectively. Mean decomposition rate ($K_d$) of Youngsan river mainstream, its tributary sites and sewage effluent were about $0.042\;day^{-1}$, $0.043\;day^{-1}$ and $0.028\;day^{-1}$, respectively and the difference was not significant between the mainstream and its tributary sites (t-test, p>0.05). $K_d$ of the sewage effluent was lower than that of stream water.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.743-752
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• 2009

One of the major problems associated with operation of domestic sewer lines involves hydraulic problems such as insufficient conveyance capacity, exceeding maximum velocity, and deficiency of minimum velocity. It has also been pointed out that influent concentration lower than design concentration of pollutants, which is mainly caused by unidentified inflow and infiltration, degrades the operational efficiency of many sewage treatment plants (STPs). A computer-added analysis method supporting a coupled simulation of sewage quality and quantity is essentially required to evaluate the status of existing STPs and to improve their efficiency by a proper sewer rehabilitation work. In this study, dynamic water quality simulations were conducted using MOUSE TRAP to investigate the principal parameters that governs the changes of BOD, ${NH_4}^+$, and ${PO_4}^{3-}$3- concentrations within the sewer networks based on data acquired through on-site and laboratory measurements. The BOD, ${NH_4}^+$ and ${PO_4}^{3-}$3- concentrations estimated by MOUSE TRAP was lower than theoretical pollution loads because of sedimentation and decomposition in the sewer. The results revealed that sedimentation is a most important factor than other biological reactions in decreasing pollutant load in the sewers of C-city. The sensitivity analysis of parameters pertaining to water quality changes indicated that the effect of the BOD decay rate, the initial DO concentration, the half-saturation coefficient of dissolved BOD, and the initial sediment depth is marginal. However, the influence of settling rate and temperature is relatively high because sedimentation and precipitation, rather than biological degradation, are dominant processes that affect water quality in the study sewer systems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.3
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• pp.198-207
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• 1990

Among the biodegradable liquid waste treatment and disposal methods, ocean dumping is a cost-effective and productive manner considering reuse point of view However, when biodegradable liquid waste is dumped in the ocean, oxygen consumption by the decomposition of organic matter must be considered. The purpose of this study is to determine the maximum allowable concentration and dumping rate in the southern waters of the East Sea based on dissolved oxygen level. Streeter and Phelps' model has been used to determine the maximum allowable concentration. Factors in this model, deoxygenation constants and reaeration coefficients, have been determined by appling oxygen consumption method and closed system model. Deoxygenation constants and reaeration coefficients from surface to each standard depth are $0.24\~0.29/day\;and\;0.03\~0.39/day$ in summer, $0.17\~0.20/day\;and\;0.04\~0.56/day$ in winter, respectively. The allowable organic matter concentration($mgBOD/\iota$) to the dissolved oxy-gen sag value of $5mg/{\iota}$ is represented $17.23\times(H)^{-0.37}$ in summer, and $64.96\times(H)^{-0.52}$ in winter by mixing depth(H, m). Csanady's experiment has been applied to estimate the optimum dumping rate. The optimum dumping rate($R,\;m^3/sec$) can be written as a product of the beam(b, m) and the draft(h, m) of vessel, and biochemical oxygen demand of waste($L_n,\;mg/{\iota}$) $R=275{\times}bh^{0.63}L_n^{-1}$ in summer $=745{\times}bh^{0.48}L_n^{-1}$ in winter. The difference of dumping rate between in summer and winter is due to the oxygen distribution.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.325-335
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• 2017

This study was carried out for 30 days in aeration type and agitation type reactor to characterize organic matter decomposition and ammonia volatilization during the liquid composting of pig slurry, and organic matter and nitrogen removal rate through mass balance analysis was analyzed. In the aeration type reactor, the pH increased from 7.0 to 9.13, and TS 34.5%, VS 33.4%, $BOD_5$ 71.2%, $COD_{Cr}$ 62.3% and TOC 83.2% were removed. In addition, 44.6% of TN and 65.0% of ${NH_4}^+-N$ were removed. In the agitation type reactor, the pH increased from 7.0 to 8.10, and the removal rates of TS 0.9%, VS 0.5%, $COD_{Cr}$ 27.5%, $BOD_5$ 28.9% and TOC 41.3% were obtained. And TN and ${NH_4}^+-N$ showed removal rate of 25.3% and 29.2%, respectively. The first order kinetics constant related to $BOD_5$ degradation was $-0.039day^{-1}$ for aerobic liquid composting and $-0.013day^{-1}$ for agitated reactor. Nitrogen loss in aerobic liquid composting was about 2.3 times higher than that of agitated reactor, whereas FAN/TAN in aerobic liquid composting was about 7.9 times higher than that of agitation type reactor. Therefore, despite the low FAN/TAN in the agitation type reactor, the nitrogen loss rate was relatively high.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.276-285
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• 2006

When polluted stream water was treated with biological aerated filter(BAF) in pilot plant, all operation with 90, 60, 45 and 30 min of EBCT at fixed $0.1m^3air/m^2min$ of aeration showed 80% or higher treatment efficiency of particle materials(SS, turbidity and Chl.-a) and 85% or higher efficiency of ammonia nitrogen removal. It was thought that, in case of BOD, biological stability may sufficiently be assured with BAF because grade III or IV inflow water was changed to grade I for outflow water. In case of $COD_{Mn}$, about 60% of removal efficiency was found. When the mechanism of the result was investigated, about 30% of COD materials was produced by algae clogged in the reactor. There was almost no biological decomposition because specific substrate utilization rate of algogenic organic materials were $0.0245mg{\cdot}COD_{Mn}/mg{\cdot}VSS{\cdot}day$, thus partial backwashing(washing the media in 1 m upper of the reactor once a day) was required. It is thought that elevation of removal rate about 10% of $COD_{Mn}$ and 5.5% of $BOD_5$ could be obtained with partial backwashing resulting in assurance of biologically more stable raw water and that saving backwashing water may be significant.

• Journal of Korean Society on Water Environment
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• v.34 no.5
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• pp.487-493
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• 2018

Urban stormwater runoff is the one of the most extensive causes of deterioration of water quality in streams in urban areas. Especially, in the Suyeong River watershed, non-point sources from urban-residential areas are the most common cause of water pollution. Also, it has been ascertained that BOD and COD as indexes of organic matter, have limitation on management of Suyeong River's water quality. In this study, changes of organic matter properties of Suyeong River from inflow of non-point source during rainfall were investigated. Fractions of organic matters were analyzed using water samples collected at two sites (Suyeong River and Oncheon Stream) during a rain event. Variations of dissolved organic carbon (DOC) concentration by rainfall were similar to flow rate change in the river. Distribution of organic matter fraction according to change of rain duration revealed that while hydrophilic component increased at initial rainfall, the hydrophobic component was similar to change in dissolved organic carbon (DOC) concentration. Also, the relative proportion of hydrophilic components in organic matter in river water increased, due to rainfall. Results of biodegradation of organic matters revealed that decomposition rate of organic matters during rainfall was higher than that of during a non-rainfall event.

• Journal of Korean Society on Water Environment
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• v.36 no.4
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• pp.314-321
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• 2020

This study evaluated the applicability of UV-AOP process using medium-pressure UV lamp and H₂O₂ to remove TOC and emerging micropollutants in the effluent from a sewage treatment plant. The UV lamp with higher output(1.6~8.0 kW) showed slightly higher amount of power in removing TOC of 1 mg/L(0.09 kWh/mg/L~0.11 kWh/mg/L), however it was found that there was no significant difference for each cases. In addition, under the condition that the H₂O₂ concentration is sufficient, as the power consumption of the UV lamp increases, the unit TOC removal concentration per unit H₂O₂ decomposition concentration also increases, resulting in effective removal of TOC. The removal rate of 7 new trace contaminants, such as antibiotics by the UV-AOP tested, was at least 89.4%, and the ability to remove the emerging micro pollutants in the process was very effective. But, it was judged that it could not be excluded that the probablity of transforming to oxidated by-product in the case of a low TOC removal efficiency. Depending on the operating conditions of the UV and H₂O₂ processes, a higher BOD concentration is found in the treated water than in the influent, and it is necessary to review the UV power and proper injection conditions of H₂O₂ to maintain the BOD concentration increase below a certain level.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.47-52
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• 2009

The aim of this study was to evaluate the effect of yeast(Saccharomyces exiguus SJPAF1, referred to as SA) addition on odor emission and contaminants reduction in piggery sluny. Four different rates of yeast addition were compared: no addition(SA0), 0.7L(SA0.7), 1.0L(SA1.0), and 1.5L(SA1.5) to one tone of piggery slurry. Odor emission tended to decrease with increasing the yeast application with concurrent effects of changes in temperature on outside of reactors. Particularly, reduction in ammonia emission was proportional to the yeast application rate; it reduced from 161.1 ppm in SA0 to 47.1 ppm in SA1.5 after 6 days of treatment Decomposition of piggery shiny by yeast increased to 13.8% more in SA1.5, and total amounts of piggery slurry decreased to 12.5% in SA1.5. Total coliforms were detected below 30MPN $ml^{-1}$ in SA1.5, while $8.3{\times}10^3$ MPN $ml^{-1}$ of Total coliforms were found in SA0. However, the effect of yeast addition in piggery slurry seemed to have no influence on the removal efficiency of contaminants such as BOD, COD, $NO_3^{-}-N$, $NH_4^{+}-N$, $PO_4^{-}P$. Consequently, the yeast(Saccharomyces exiguus SJPAF1) addition of 1.5% in the piggery sluny seems to have potential applicability for improving agent of pig-farm environment.