• Journal of Environmental Science International
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• v.20 no.6
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• pp.767-773
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• 2011

The objectives of this research are to investigate the proper coagulation conditions which are a type and doses of coagulants, mixing conditions (velocity gradients and mixing times), pH and so on through Jar-test, to evaluate the flux variations, permeate, backwashing according to characteristics of pretreatment of the wastewater by means of MF membranes for river maintenance water reuse. The effluent water from B-city K-sewage treatment plant are used for this research. Turbidity and suspended solids(SS) are 14.2 NTU and 10.4 mg/L respectively. This condition causes fouling for membrane process. The flux decline could be reduced when coagulation pretreatment was carried out. Optimal coagulations PAC which are commonly used in the sewage treatment plant was observed in this research. The results indicate that an optimal coagulation dose and pH are 80 ppm and pH of 7 respectively, but coagulation efficiency was lower at strong acid or strong base. Results showed that continuous and steady operations in membrane separation process by means of the effective removal of organic matter and turbidity with coagulation pretreatment of sewage secondary effluent were achieved.

• Membrane Journal
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• v.15 no.3
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• pp.241-246
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• 2005

This study is investigated for the applications of MBR SYSTEM using $ENVIS^{(R)}$ which is a submerged flat membrane for treatment of sewage and wast water. The experiment was practiced on the scene of labor that are sewage facilities of factories $(10\;m^3/day)$ and wast water treatment plant $(30\;m^3/day)$ using equipments made by Pure-Envitech Co., LTD. SS, BOD and COD for the result of removal efficiency at the sewage facilities of factories were $99.7\%,\;97.6\%$, and $96.8\%$, rspectively. SS, BOD and COD for the result of removal efficiency at the waste water treatment plant were $99.6\%,\;95.6\%,\;and\;80.3\%$, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.4
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• pp.337-348
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• 2018

As the issue of microplastics (MPs) detection in tap water was raised in other countries in 2017, monitoring of MPs in drinking and source water, and sewage treatment plant (STP) effluents was initiated. This study intends to look into other studies on MPs in STPs at home and abroad, and review the characteristics of MPs and their removal efficiencies in the STPs, the risk and effect of MPs on watersheds, and management practices in order to help better understand MPs in STPs. To manage MPs effectively in STPs, it is necessary to investigate the detection of MPs discharged from STPs, do research on human health risk and control measures, and build a monitoring system including standardized analytical methods.

• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.61-69
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• 2002

Oship stream is located nearby south eastern coasts. This study was performed to find out waters quality modeling and then to predict water quality of Oship stream. Based on survey data, BOD, T-N, T-P calibration and verification result were in good agreement with measured value within mean coefficient variance(MSE) value, which were 13.9%, 9.0%, 26.5% and 19.5%, 12.0%, 16.5%, respectively. Sectional water quality predictions of the main stream of Oship stream are executed on the basis of the following cases 1) with sewage treatment of Dogye-eup 2) reduction of mine wastewater treatment of 80% in th basin. As a result, BOD, T-P improvement rates at down stream of Oship stream, case 1) were appeared 12.2%, 22.2%, case 2) maximum sulfate ion and conductivity reduction removal rate of Oship stream were 58%, 68%. The main pollution sources of Oship-stream were almost domestic wastewater and mine wastewater discharged from Dogye-eup which located in uppers stream. The large effects will appear after the construction of Dogye sewage water treatment plant which remove the organic matter and nutrients in these sewage water. The waste water from mine can not easily to treat for characteristics of effluence and economic problems. However, to achieve the goal of water quality in Oship-stream water system, treatments of those are necessary.

• Journal of Industrial Technology
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• v.31 no.A
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• pp.135-145
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• 2011

This study was conducted to analyze the cost effectiveness in line with total phosphorus standard enforcement of public sewage treatment facilities. The additional cost for the total phosphorus removal process was calculated to analyze the cost effectiveness of the advanced water purification process. The analysis results showed that the T-P removal by coagulation sedimentation was more efficient than the advanced water purification facilities in terms of facilities investment cost, and if the coagulation filteration was used for T-P removal, the activated carbon process among the advanced water purification techniques was more efficient in terms of facilities investment cost. In this study, the effects of the T-P removal process that will be additionally introduced according to the tightening of the effluent T-P standard were analyzed within a limit. The actual benefits of improved T-P concentration in the water source will provide diverse values, including the leisure water, environment improvement water, eco-system in the water source and industrial water, in addition to the advanced water purification.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.06a
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• pp.95-112
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• 1998

Water quality in the public water course has been polluted more seriously than ever before due to the increase of the number and aremount of pollution sources such as domestic and industrial wastewater. For water quality conservation, the Korean government has been trying to construct sewage treatment facilities continually, of which treatment capacity reached to 11,452,400m$^{3}$/day in 1996. Night soil treatment facilites of m nationwide have the treatment capacity of 24,038m$^{3}$/day. But water quality has not been improved because the sewer systems were insufficient and the treatment efficiencies of sewage were not high, enough. For renovation of water quality, miscellaneous domestic wastewater must be treated because 27g BOD/day out of total 40g BOD/person-day come from miscellaneous wastewater, comparing to 13g BOD/day from night soil. However, sole treatment purifier treat only night soil from the flushing toilet. Therefore, it may be desirable to treat the miscellaneous domestic wastewater and the night soil from flushing toilet together by joint treatment purifier system as on-site domestic wastewater treatment technology. In Korea, the joint treatment purifier system, introduced in 1997, have the benefit as follows; i) good water poiluion control effect, ii ) good effect on river water flow, iii) water pollution control with sewage treatment facility, and iv) rapid pollution control effect, etc. In order to achieve a good effect as stated before, i ) strengthening effluent guideline including BOD, nitrogen and phosphorus, ii ) specializing operation to maintain high performance, and iii) supporting its construction and maintenance costs by the governmental level may be necessary: In addition, automation system of joint treatment purifier, technology for its package and compactness, and a new bio-media bio-filter with higher capacity should be further developed in agreement with a more stringent effluent guideline.

• Journal of Environmental Science International
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• v.22 no.12
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• pp.1643-1650
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• 2013

This study investigated water quality of effluents and stream from the sewage treatment plants located at Gumi Complex 4, Gumi, and Wonpyeong in Gumi. Downstream region was found to increase the concentration of nutrients for sewage treatment plant effluent. Both phosphorus and nitrogen were accounted most as soluble form. In particular, the high ratio of dissolved effluent of sewage treatment plants were investigated. In the streams, Phosphorus concentration was high during rainy season and nitrogen concentration was high in the dry season. Sewage treatment plant effluent was relatively less microbial activity and nutrient concentrations were higher in the winter. TN/TP ratio was the highest in the upstream region and the lowest in the sewage treatment plant effluent. The effect of the nutrient matter from a discharge of a sewage treatment plant on rivers varied depending on the size of the river and the treatment plant. However, the influence of the concentration was greater than that of flowrate. Sewage treatment plant effluent loads phosphorus, nitrogen accounted for 8% and 6% respectively at the point N3 of the Nakdong river.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.4
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• pp.96-105
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• 2000

Field experiment was performed from August 1996 to December 1999 to examine the performance of constructed wetland system for wastewater treatment in rural area. The constructed wetland system was installed in Konkuk University and the effluent from septic tank of school building was used as an influent to the treatment basin. The treatment basin was composed of sand bed with planted reed. From August 1996 to June 1998 the hydraulic loading rate was fixed with about 15.63cm/day and theoretical detention time was 1.38 days, and from July 1998 to December 1999 the hydraulic loading rate was about 6.25cm/day and theoretical detention time was 3.5days. It worked continuously even during winter time, and the sewage flowed without freezing even when average daily air temperature was below -1$0^{\circ}C$. Average removal rate of BOD , COD, and SS was about 70%, T-P removal rate was about 50.8% , and T-N removal rate was 23.9%. The reason for poor T-N removal might be due to high influent concentration and short retention times. At the later years BOD and COD removal rates were increased , and SS and T-P removal rates did not change significantly , but T-N removal rates were decreased. The effluent of the wetland system often effluent water quality standards for sewage treatment plant, therefore, further treatment would be required if the effluent need to be discharged to the public water. Wetland system involves relatively large land area and could be suitable for rural area. Therefore, utilization of reclaimed sewage for agricultural purpose or subsequent land treatment is recommended as a ultimate disposal of sewage for agricultural purpose or subsequent land treatment is recommended as a ultimate disposal of sewage in rural area.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2003.10a
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• pp.105-126
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• 2003

In Korea most of annual rainfall is concentrated in several episodic heavy rains during the season of summer monsoon and typhoon. Because of uneven rainfall distribution many dams have been constructed in order to secure water supply in dry seasons. The Han River system has the most dams among Korean rivers, and the river is a series of dams now. Reservoirs need different strategy of water quality control from river water. Autochthonous organic matter and phosphorus should be the major target to be controlled in lakes. In this Paper some problems are discussed that makes efforts of water quality improvement ineffective in lakes of Korea, even after the substantial investment to wastewater treatment facilities.1) Phosphorus is the key factor controlling eutrophication of lakes and the reduction ofphosphors should be the major target of water treatment. However, water quality management strategy in Korea is still stream-oriented, and focused on BOD removal from sewage. Phosphorus removal efficiency remains as low as 10-30%, because biological treatment is adopted for both secondary treatment and advanced treatment. The standard for TP concentration of the sewage treatment plant effluent is 6 mgP/l in most of regions, and 2 mg/l in enforced region near metropolitan water intake point. TP in the effluents of sewage treatment plants are usually 1-2 mg/1, and most of plants meet the effluent regulation without a further phosphorus removal process. The generous TP standard for effluents discourages further efforts to improve phosphorus removal efficiency of sewage treatment. Considering that TP standard for the effluent is below 0.1 mg/l in some countries, it should be amended to below 0.1 mg/l in Korea, especially in the watershed of large lakes.2) Urban runoff and combined sewer overflow are not treated, even though their total loading into lakes can be comparable to municipal sewage discharges on dry days. Chemical coagulation and rapid settling might be the solution to urban runoff in regard of intermittent operation on only rainy days.3) Aggregated precipitation in Korea that is concentrated on several episodic heavyrains per year causes a large amount of nonpoint source pollution loading into lakes. It makes the treatment of nonpoint source discharge by methods of other countries of even rain pattern, such as retention pond or artificial wetland, impractical in Korea.4) The application rate of fertilizers in Korea is ten times as high as the average ofOECD countries. The total manure discharge from animal farming is thought to be over the capacity of soil treatment in Korea. Even though large portion of manure is composted for organic fertilizer, a lot of nutrients and organic matter emanates from organic compost. The reduction of application rate and discharge rate of phosphorus from agricultural fields should be encouraged by incentives and regulations.5) There is a lot of vegetable fields with high slopes in the upstream region of the HanRiver. Soil erosion is severe due to high slopes, and fertilizer is discharged in the form of adsorbed phosphorus on clay surface. The reduction of soil erosion in the upland area should be the major preventive policy for eutrophication. Uplands of high slope must be recovered to forest, and eroded gullies should be reformed into grass-buffered natural streams which are wider and resistant to bank erosion.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.6
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• pp.559-572
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• 2018

The aim of this study was to evaluate pretreatment methods for 27 pharmaceuticals and personal care products (PPCPs) in various sewage samples using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) and online solid-phase extraction with LC-MS/MS. Extraction efficiencies of PPCPs in the solid phase under different experimental conditions were evaluated, showing that the highest recoveries were obtained with the addition of sodium sulfate and ethylenediaminetetraacetic acid disodium salt dehydrate in acidified conditions. The recoveries of target compounds ranged from 91 to 117.2% for liquid samples and from 61.3 to 137.2% for solid samples, with a good precision. The methods under development were applied to sewage samples collected in two sewage treatment plants (STPs) to determine PPCPs in liquid and solid phases. Out of 27 PPCPs, more than 19 compounds were detected in liquid samples (i.e., influent and effluent) of two STPs, with concentration ranges of LOQ-33,152 ng/L in influents and LOQ-4,523 ng/L in effluents, respectively. In addition, some PPCPs such as acetylsalicylic acid, ibuprofen, and ofloxacin were detected at high concentrations in activated sludge as well as in excess sludge. This methodology was successfully applied to sewage samples for the determination of the target compounds in STPs.