• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1090-1097
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• 2006

The anoxic activated sludge process was applied to the treatment of industrial box-mill wastewater, which exhibited the high removal efficiencies of $90{\sim}94%$$ TCOD_{Mn}$ and $58{\sim}81%$ Color. For the design of industrial anoxic activated sludge process, Monod bio-kinetic coefficients of box-mill wastewater were estimated as follows: $K_{max}$(maximum specific substrate removal rate)=0.52 $day^{-1}$, $K_s$(half saturation constant)=314 mg/L, $K_d$(decay coefficient)=0.274 $day^{-1}$, y(microbial yield coefficient)=0.908 mg/mg, and ${\mu}_{max}$(maximum specific growth rate)=0.472 $day^{-1}$. Space loading factors for the design analysis were practically determined as the values of F/M ratio=$0.043{\sim}0.07$ kg-$TCOD_{Mn}$/kg-SS-day, BOD space loading=$0.18{\sim}0.3$ kg-$TCOD_{Mn}/m^3-day$, and ${\theta}_x=6.8{\sim}26.4$ day when considering the relationship of these loading factors with growth dynamics of microorganisms, the F/M ratio that is inversely proportional to ${\theta}_x$ should be equivalent to ${\mu}_{max}$ in units, but exhibited the significant difference between theses two values. Therefore, it is considered that high safety factors are requested in the design of anoxic activated sludge process that is based on Monod bio-kinetics of microorganism.

• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.816-821
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• 2010

It has been achieved 109.1 kg/d of BOD reduction that is equivalent to the amount of BOD loading discharged from 21,880 persons and dramatic decrease of the fallout ratio against water quality of effluent, from 42% to 9%, through technical support on ISTPs to be applied by the ISMSGA at the upper area of Geongan river in Yong-In city. It was clearly revealed that the most efficient configuration for ISTP was a series of anaerobic tank, equalization basin, aerobic tank, sedimentation tank, and then effluent tank. Also, the major causes on the fallout ratio of ISTP resulted in the lack of management (67.5%) and imperfect facilities (32.5%). Then, when compared the quantity of water supply with the design capacity of ISTP, the design capacity was estimated as 1.8 or 2.4 folds larger than the real quantity of water supply so that it is essential to punctually consider the key factors such as an estimation methods, the specificity of commission operator and construction by high systematic technologies to improve the water quality for the future.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.4
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• pp.55-63
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• 2012

This study was performed to investigate the stream water quality characteristics in Hengjeong Bridge Basin of Dongjin River during twelve months from October, 2010 to September, 2011. Also, pollutant loads were calculated on the basis of the water quality and runoff results. The results showed that ranges of water temperature, pH and EC were $6.2{\sim}23.90^{\circ}C$, 6.32~7.78, $84.4{\sim}126.5{\mu}S/cm$ respectively. The Concentration of DO, BOD, COD, SS, Tot-N and Tot-P were observed as 6.80~9.20 mg/L, 0.40~1.60 mg/L, 1.96~4.41 mg/L, 59.60~142.20 mg/L, 1.28~3.52 mg/L, 0.001~0.07 mg/L respectively. Tot-N showed correlativity with BOD, and Tot-P showed correlativity with SS. The runoff pollutant loading of Tot-N and Tot-P were 117.94 kg/ha and 2.06 kg/ha respectively, in Hengjeong bridge of Dongjin river watershed. In the case of the correlativity between runoff pollutant loads and concentrations, Tot-N and Tot-P show low significant relationships.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.3
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• pp.357-365
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• 2004

Effect of artificial circulation on amelioration of water quality in Yeoncho Lake was analyzed using summer data between 1991-2002. Two sites, intake tower area where aeration systems are concentrated in and near the inlet of reservoir were selected for comparison in this study. Summer averages between may and september Showed that aeration system might be beneficial in the improvement of water quality of BOD5, COD, and TN while Chl-a concentration and transparency did show opposite pattems. Wilcoxon's singed rank test for matched pair indicated slight increase of BOD5 and COD concentrations in the vicinity of intake tower while other variables did not show any significant differences from data of inlet of reservoir. During the study, it was found that the following subjects need to be investigated for more detailed analysis. 1) Dynamic pollutant loading from outside and inside the lake, 2) Biological, Chemical and Physical lake data when aeration systems are in and not in operation and 3) Radius of influence of aeration system.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.5
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• pp.86-92
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• 1999

Effluent concentration estimation equations for wetland system were developed throught statistical analysis of treatment wetland experimental data. Existin g empirical equations were reviewed for thier accuracy with experimental data, and compared with the estimatin equations. About 70 experimental data sets were used for multiple regression, and variables include influent concentration, hydraulic loading rate, average daily air temperature , and plant coverage. The estimatin equations developed for BOD5 , SS ,T-P, and T-N predicted effluent concentrations moderately well, and coefficient fo determination ($R^2$) for them was 0.74 , 0.60, 0.59 and 0.58 respectively. The equations obtained from same data but excluding plant coverage showed relatively lower $R^2$ than the former case, and it was 0.66, 0.52, 0.41 and 0.57 respectively. The EPA, WPCF , and Kadlec and Knight equations worked poorly and $R^2$ for them was significantly lower than the estimation equation developed in the study. The reason might be that the existing equations were oversimplified that they did ot include important parameters such as air temperature and plant coverage. Therefore, developing reasonable estimation equations from experiment under realistic condition is highly recommended rather than using exiting estimation equations.

• Membrane and Water Treatment
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• v.7 no.1
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• pp.11-22
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• 2016

The characterization of treatment performance with respect to mixed liquor suspended solids (MLSS) concentration enables greater control over system performance and contaminant removal efficiency. Hybrid membrane bioreactors (HMBRs) have yet to be well characterized in this regard, particularly in the context of greywater treatment. The aim of this study, therefore, was to determine the optimal MLSS concentration for a decentralized HMBR greywater reclamation system under typical loading conditions. Treatment performance was measured at MLSS concentrations ranging from 1000 to 4000 mg/L. The treated effluent was characterized in terms of biochemical oxygen demand ($BOD_5$), chemical oxygen demand (COD), turbidity, ammonia ($NH_3$), total phosphorus (TP), total kjeldahl nitrogen (TKN), and total nitrogen (TN). An MLSS concentration ranging from 3000 to 4000 mg/L yielded optimal results, with $BOD_5$, COD, turbidity, $NH_3$, TP, TKN, and TN removals reaching 99.2%, 97.8%, 99.8%, 99.9%, 97.9%, 95.1%, and 44.8%, respectively. The corresponding food-to-microorganism ratio during these trials was approximately 0.23 to 0.28. Operation at an MLSS concentration of 1000 mg/L resulted in an irrecoverable loss of floc, and contaminant residuals exceeded typical guideline values for reuse in non-potable water applications. Therefore, it is suggested that operation at or below this threshold be avoided.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.403-409
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• 2007

This study was carried out to recommend the systematic improving practice for the effective operation of septic tank, and the evaluation of its BOD and nutrient removal efficiency depending on process, the survey of characteristics of FRP material, and the suggestion of optimum septic tank model within sewage treatment area. The average BOD concentration and BOD removal efficiency of septic tank which was carried out the cleaning periodically in 63.9 mg/L and 77.8%, shows good quality better than the septic tank which was not carried out the cleaning regularly. Maximum load of tensile, flexural and compressive strength increased in proportion to its thickness, and the contents standard 25% of glass fiber required upgrade over than 30%. Configuration and performance for the optimum of the septic tank suggests that over $0.75m^3$ of the effective total volume, adding to over $0.25m^3$ a man for more than 5 men of the treated person, retention time should be within one day. Improving plans about facility and materials quality of the septic tank have an obligation that protective wall ought to install on the concrete bottom and side faces to prevent crumble or transform from loading of the ground or upper part of the structure on the tank setting. And it is eliminated the uneffective resisting pressure and it keeps off circulate imperfect products by strengthening of the test methods such as stretching strength, pressing strength, glass fiber contents and thickness.

• Journal of Wetlands Research
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• v.6 no.2
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• pp.57-63
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• 2004

More than 1000 natural and constructed wetlands have been used to improve water quality. The general results showed that the highest removal efficiency was 84% for BOD and the lowest one was 48% for total nitrogen concentration. In addition, total phosphous removal efficiency was 67%, and the removal efficiencies are related to inflow loading. Researches donducted in Korea have focused on input-output mass balance and uptake by aquatic plant. As such little information if available about complex processes regulating water quality and role of microbes. Therefore, to determine the optimal design for construct, and methods to operate constructed wetland, researches about complex mechanisms of contaminant removal and interdisciplinary researches are necessary.

• Journal of Environmental Science International
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• v.7 no.6
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• pp.845-851
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• 1998

In order to manage the water quality from the flowing streams in Cheju Island, the characteristics of water quality was investigated from August, 1996 to May, 1997 and the pollutant loadings for future were estimated from the watershed at each stream. Comparing the mean concentrations of each water quality with the criterion of water quality in river, it was under I class except for Changgo Stream, for DO, under I class at the whole station for SS and under II class for BOD. As the pollutant loadings at each stream in 2020 is compared with those in 1996, the estimated results are as follows : 1) for BOD, 59% at Donghong Stream, 24% at Yeonoe Stream, 44% at Ohngpo Stream and 57% at Changgo Stream. 2) for T-N, 91% at Donghong Stream, 76% at Yeonoe Stream, 63% at Ohngpo Stream and 89% at Changgo Stream. 3) for T-P, 69% at Donghong Stream, 42% at Yeonoe Stream, 45% at Ohngpo Stream and 73% at Changgo Stream. The point source loadings discharged through combined sewer could be treated at sewage treatment plant. However, the expected slow decreasing rate of BOD, T-N, and T-P loadings is due to the part of untreated nonpoint source loadings. Nonpoint source loading overflow typically occurs when the flow of stormwater combined with sewage exceeds the capacity of the interceptor sewers. Since most of the sewers used in Cheju Island are the combined sewers, the combined overflow sewage is bypassed into the receiving water area after a rainstorm. Therefore, a means to control nonpoint source loadings should be considered for the river and marine water quality management.

• Korean Journal of Environmental Agriculture
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• v.19 no.5
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• pp.426-432
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• 2000

Field experiment was performed from August 1996 to December 1999 to examine the feasibility of constructed wetland system for sewage treatment in rural areas. A pilot system was installed in Konkuk University and the effluent of septic tank for school building was used as an influent to the wetland treatment basin. The system was composed of sand and reed, and operated continuously including winter time. Average removal rate of about 70% was observed for BOD, COD, and SS, about 50% for T-P, and about 25% for T-N. The reason for poor T-N removal might be due to high loading rate and short retention time. The system demonstrated satisfactory effluent concentration and stable performance in growing season. And it also worked adequately in wintertime even below $10^{\circ}C$ without freezing, and removal was still significant. The amount removed in BOD, COD, and SS was almost the same as in the growing season, and the amount removed in nutrients was about half of the one in growing season. Overall performance of the experimental system was compared with existing data base (NADB, 1994), and it was within the range of general system performance. As study period increased, removal rates for BOD, COD, SS, and T-P were consistently maintained and even enhanced, but removal rate for T-N decreased slightly. Wetland system was thought to be a feasible alternative for sewage treatment in rural area considering its low cost and low maintenance requirement. However, the effluent of the experimental wetland system often exceeded current effluent water quality standards, therefore, further treatment could be required if the effluent should be discharged to public waters. Wetland system of interest locates in rural area and is a part of rural ecosystem, therefore, ultimate disposal of reclaimed sewage for agricultural purpose or subsequent land treatment might be available and further research in this matter is recommended.