• Journal of Wetlands Research
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• v.19 no.1
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• pp.69-79
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• 2017

Protected area of water for supply source is located mostly of rural area in Korea. Normally, sewage treatment system is poor to manage in rural, because low population and density. Rural area need sewage treatment system to supervise supply source of water. In this study, analysis on operation result of 4 RCSTP and MWTP is located at the rural area. Higher concentration of pollutant were inflows to MWTP than RCSTP, and effluent quality standard is satisfaction. However, RCSTP effluent pollutant concentrations was researched higher than MWTP. The organic matter(BOD, COD) were about 5% of a high treatment efficiency to a median. The nutrient(T-N, T-P) were detected Up to high 30%. Also, we analyzed to effect reactor operational parameters on the pollutant treatment efficiency like mixed liquer suspended solid(MLSS), dissolved oxygen(DO) and sludge retention time(SRT). As a result, pollutant treatment efficiency showed fluctuation in accordance with operating condition. Thus, it is necessary to manage the reactor operation condition for management of rural area sewage treatment.

• Membrane Journal
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• v.22 no.2
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• pp.95-103
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• 2012

To treat nitrate and non-biodegradable organics effectively in sewage, industrial wastewater and livestock wastewater, the activated sludge process integrated by a membrane separation and a porous electrode- electrolysis was proposed and its efficiency was investigated. The proposed system was consisted of 3 processes; activated sludge, membrane filtration and electrolysis. In the study, the membrane filtration played a role in reducing the load of the electrolysis to operate the proposed process stably. The electrolysis consisted of a porous electrode to increase the efficiency due to the extension of the specific surface area. Additionally, redox reaction in the electrolysis was induced by decomposing influent water as current was applied. As a result, hydrogen free radicals and oxygen radicals as intermediates were produced and they acted as oxidants to play a role in decomposing non-degradable organics. It was environmentally-friendly process because intermediates produced by porous electrode were used to treat waste matters without supplying external reagent. Experimental data showed that the proposed process was more excellent than activated sludge process. SS removal efficiencies of the proposed process, membrane filtration and activated sludge process were about 100%, about 100% and about 90%, respectively. COD removal efficiencies of the proposed system, membrane filtration and activated sludge process were about 92%, about 84% and about 78%, respectively. T-N removal efficiencies of the proposed system, membrane filtration and activated sludge process were about 88%, about 67%, and about 58%, respectively. The SS data showed that SS was efficiently removed in the single of the membrane filtration. The COD/T-N data showed that COD/T-N of membrane hybrid process was treated by removing a little soluble organics and SS, and that COD/T-N of electrolysis hybrid process was treated by oxidize organics with high removal rate.

• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.787-797
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• 2003

The characteristics of concentrations and loads of Total Nitrogen(T-N), Total Phosphorus(T-P), and Chemical Oxygen Demand (COD) in mountain stream water were examined from September 2000 through August 2001. The 92.5-ha study watershed in Chungbuk Province consists of 59% mixed forest and 30% coniferous forest. Streamflow was measured and water samples were collected at about 10 day intervals for dry days and at 2-6 hour intervals for a storm event at the study watershed outlet. The mean concentration of COD in streamflow for rainy days was significantly (p < 0.05) higher than for dry days. The mean concentrations of T-N and T-P in vegetation growing season (May to October) were lower than those in vegetation dormant season (November to April). Low concentrations of pollutants during vegetation growing season are likely due to the heavy demand for nutrients by the vegetation and biological activity associated with a warming of soil. The ratios of pollutants loads during storm periods to annual pollutants loads were 87% for T-N, 83% for T-p, and 87% for COD. The unit loads of pollutants for study area were estimated at 5.9 kg/ha $\cdot$ yr for T-N, 0.15 kg/ha $\cdot$ yr for T-p, and 23.9 kg/ha $\cdot$ yr for COD. The removal efficiency of pollutants in study area were 24% for T-N, 58% for T-P and 66% for COD, indicating that a study area shows water purification function.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.3
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• pp.189-194
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• 2012

In this study, a 3-stage biological aerated filter (BAF) system was proposed to enhance nitrogen removal in the treatment of low carbon to nitrogen ratio (C/N ratio) municipal wastewater. Laboratory experiments were conducted to evaluate the effects of dynamic-flow at the HRT of 6 h. Results of the long-term operation of 3-stage BAF systems showed that the dynamic-flow enabled the total nitrogen removal (T-N) removal efficiency of the system to be about 7 % higher than that of non-dynamic-flow system in treating domestic wastewater due to the more efficient use of organic substrates. The overall $NH_4$-N removal performance was stable during the operational period due to the unique system configuration where independent nitrification occurred. It was concluded that the 3-stage BAF system proposed in this study provided excellent performance in the removal of nitrogen by employing dynamic-flow and three columns functioning as sorption, denitrification and nitrification, respectively.

• Journal of the Korean GEO-environmental Society
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• v.11 no.5
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• pp.5-13
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• 2010

The research is intended to develop and verify a biological complex soil treatment process to treat and restore soil and groundwater which is contaminated with oil, heavy metals, and nutrients through experiments with the series of treatment process such as bioreactor, rolled pipe type of contact oxidation system(RPS), and chemical processing system. 5 microbial strains were separated and selected through experiment, whose soil purification efficiency was excellent, and it was noted that anion- and nonion-series of complex agent was most excellent as a surfactant for effectively separating oils from soils. Method to mix and apply selected microbes after treating the surfactant in the contaminated soil was most effective. The removal efficiencies of total petroleum hydrocarbon (TPH)-contaminated soil about 5,000mg/L and above 10,000mg/L were approximatly 90.0% for 28 days and 90.7% for 81 days by soil remediation system and the average removal efficiencies of BOD, $COD_{Mn}$, SS, T-N, and T-P in leachate were 90.6, 73.0, 91.9, 73.8, 65.7% by the bioreactor and RPS. The removal efficiency was above 99.0% by chemical processing system into cohesive agents.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.344-350
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• 2012

BACKGROUND: To design and develop a constructed wetland for effective livestock wastewater treatment, it is necessary to understand the removal mechanisms of various types of pollutants in constructed wetlands. The objective of this study was to evaluate the treatment efficiency of pollutants under different types of fraction in constructed wetland system for treating piggery wastewater. METHODS AND RESULTS: The piggery wastewater treatment plant that consisted of activated sludge tank, aerobic and anaerobic beds was constructed. The concentration of COD(Chemical oxygen demand) in effluent by fraction was 71.5 mg/L for soluble COD, 142 mg/L insoluble COD. The concentration of SS(Suspended solid) in effluent by existing form was 102 mg/L for volatile SS, 15.5 mg/L for fixed SS. The concentration of T-N(Total nitrogen) and T-P(Total phosphorus) in effluent by existing form were 12.8 mg/L and 3.05 mg/L for dissolved form, 35.0 mg/L and 1.93 mg/L for suspended form. The removal efficiencies of COD, SS, T-N and T-P in hot season(summer and autumn) were higher than those in cold season(spring and winter). The removal efficiencies of COD, SS, T-N and T-P in effluent were 98.0, 99.0, 98.2 and 99.2% for all seasons, respectively. CONCLUSION(S): The results indicated that removal types of pollutants were insoluble COD(ICOD), volatile SS(VSS), dissolved T-N(DTN) and dissolved T-P(DTP) in constructed wetlands for treating piggery wastewater.

• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.53-59
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• 2018

Water pollution is drastically increasing day by day, because of the enhancement in use of livestock, urban sewage detergents and fertilizers. Moreover increase in concentration of phosphorous and nitrogen contained in sewage, leads to green tide problem in the rivers and causes marine pollution. For this problem to solve, several technologies are being researched and developed. Among them, this experiment is a study on Bench-scale STP based on internationally certified sewage treatment equipment by MEPC. 227(64) of IMO. The purpose of this study is to compare the biological treatment efficiency of phosphorus of Bench-scale STP. The ratio of C : N : P was set to 10 : 5 : 3 and 10 : 3 : 1 as the operating conditions. And the operation cycle was set to anoxic(mixed) 70 min - aeration 50 min (70-50), anoxic(mixed) 90 min - aeration 60 min (90-60). As a result, the phosphorous treatment efficiency was 88% at average, and the treatment efficiency was steady at 90-60 better than 70-50. The efficiency of the bench-scale STP has been verified through this experiment and additional experiments are required to derive the optimal operating conditions.

• KSBB Journal
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• v.21 no.4
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• pp.317-323
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• 2006

This study focused on the availability of wastewater reclamation and reusing system as one of the alternatives against the global water shortage in near future, which system is composed of two treatment steps; first, wastewater is injected into upflow $A^2O$ biofilm process(anaerobic/anoxic/oxic) reactor filled with polyethylene fixed-media, and the effluent of 1st steps continuously passed through downflow nano silver sand filter. The pH of the effluent ranged from 7.39 to 8.06(average 7.84), the $COD_{Mn}$ was $8{\sim}18mg/L$(average 12.1 mg/L), and $BOD_5$ was $2.1{\sim}10.0mg/L$(average 4.9 mg/L), that met all the wastewater reclamation and reusing system criteria. Besides, the SS concentrations of the effluent which was $3{\sim}9mg/L$(average 4.95 mg/L) met the criteria(5 mg/L), showing 94.8% of average removal efficiency. The 99.1% of the average removal efficiency of the E-coliform did not met the criteria(Not detected), which indicates the needs for the following chlorine disinfection treatment with the residual chlorine concentration of above 0.2 mg/L. There are no bacteria on the sand surface coated by nano silver. The removal efficiency of T-N and T-P that could be included into the criteria in the future was 50.3% and 27.2% respectively.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.481-488
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• 2006

The field scale experiment was performed to examine the performance of the constructed wetland for nonpoint source (NPS) pollution loading reduction. Four sets (0.88 ha each) of wetland and pond system were used. After three growing seasons of the wetland construction, plant coverage increased to about 90% even without plantation from bare soil surfaces at the initial stage. During the start up period of constructed wetlands, lower water levels should be maintained to avoid flooding newly plants, if wetland plants are to start from germinating seeds. The average removal rate of $BOD_5$, TSS, T-N and T-P during the first two years was 5.6%, 46.6%, 45.7%, and 54.8%, respectively. The $BOD_5$ removal rate was low and it might be attributed to the low influent concentration. The early stage of wetland performance demonstrated the effectiveness of water quality improvement and was satisfactory for treating polluted stream waters. From the first-order analysis, T-P was virtually not temperature dependent, and $BOD_5$ and TSS were more temperature dependent than T-N. A pond-wetland system was more effective than a wetland-pond or a wetland alone system in water quality improvement, particularly to reduce T-P. Overall, the wetland system was found to be an adequate alternative for treating a polluted stream water with stable removal efficiency and recommended as a NPS control measures.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.4
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• pp.56-63
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• 2001

This paper presents treatment efficiency and plant growth of a subsurface-flow constructed wetland system (23 m in length, 6.5 m in width, 0.65 m in depth) over one year after its establishment on floodplain of a stream in June 2000. An upper layer of 10 cm in depth was filled with course sand and the main biological layer of 50 cm depth with crushed stone with 8 - 15 mm in diameter. The system was planted with common reeds (Phragmites australis) grown on pots. Effluent discharged from a secondary-level treatment plant was funneled into it. Reed stems emerging in April 2001 grew up to 145.9cm until July 2001. The number of reed stems in July 2001 increased by about 11 times compared with that just after planting. The system was inundated seven times by storms over the monitoring period. Reeds were slightly bent after flooding, however they returned to almost upright standing in a couple of weeks. Small portion of inside slope of berm was eroded and the system surface had a sedimentation of 2 - 3 mm in depth. The average removal rates for SS, $BOD_5$, T-N and T-P was 73%, 70%, 53%, and 72%, respectively. The purification efficiencies for SS and $BOD_5$ were fairly good. The reduction rates for T-N was relatively low for the period of late fall through winter until early spring due to lower water temperature which retarded microbial nitrification and denitrification mechanisms. Reduction in the concentration of T-P during fall and winter was relatively higher than that during spring. Leach of phosphorous from plant litters lying on system surface and slight resuspension of precipitated phosphorous in substrates resulted in lower reduction for T-P in spring.