• Journal of Korean Society of Environmental Engineers
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• v.35 no.6
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• pp.407-414
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• 2013

Full scale livestock wastewater treatment plant (100 t/d) was constructed and operated to develop compact and cost effective treatment process for public plant as well as individual farm. Liquid form of livestock wastewater after belt press filter was treated through MBR/NF/RO. NF/RO brine water was mixed with livestock wastewater sludge and treated using denitrification, coagulation and air flotation process. Mixed effluent of NF/RO and air flotation meet public livestock wastewater treatment standard, BOD, T-N and T-P, 30 mg/L, 60 mg/L, 8 mg/L below, respectively. Condensed sludge of air flotation returned belt press filter. Dewatered cake contained 90% water and could be used fertilizer after mixing sawdust.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.523-532
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• 2011

In this study, from 2004 to 2008 influents and discharging effluents from 241 municipal public sewage treatment plants were surveyed. Statistics including average, Coefficient of Variation (CV) and Coefficient of Reliability (COR) for each season, time series analysis for removal efficiency and water quality of effluents, and a comparison of the effluent standards in Korea and other countries were presented. The average concentrations of TN and TP in influents. during winter season were 32.6 and 3.78 mg/L and during other season were 30.8 and 3.61 mg/L in 2008, respectively. The average TN concentration on the basis of the maximum monthly concentrations in the effluents during winter season ranged from 14.2~17.4 mg/L and during other season ranged from 12.2~14.8 mg/L. The TP concentration in the effluents depending on the each season was no big difference. TN removal efficiency decreased from Jan. to Feb. and TP removal efficiency decreased in Jan., Jun and July. Maximum COR during winter season were 0.61 but the COR for TN and TP during other season ranged from 0.96~1.48 and 1.09~1.81, respectively, due to big difference in the standard for TN and TP in effluents depending on the season. TN and TP standards for effluent of sewage treatment during winter season in Korea was much higher than those in other countries. Therefore the lower effluent standards during winter season is essential for the water quality improvement.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.108-108
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• 2019

낙동강에는 2010-2012년 4대강 사업 완료 후 8개의 다기능 보가 설치되었다. 보 설치로 인해 물의 체류시간이 증가하고 보 상류에는 정체수역이 광범위하게 형성되었다. 이후 지속된 가뭄과 여름철 고온현상이 겹치면서 남조류의 과잉성장(녹조현상)이 빈번히 발생하여 수생태계 건강성에 문제를 초래하는 등 사회적 이슈로 자리잡게 되었다. 조류의 과잉성장을 해결하기 위해 정부에서는 총인(TP) 방류수 수질기준 강화, 펄스형 방류기법 운영 등 대책을 추진하였으며, 녹조 우심지역을 선정하고 지역 특성에 맞는 대응방안을 수립하여 추진하고 있으나, 그 효과가 국부적이고 일시적이어서 근원적 대책 마련이 필요한 실정이다. 일반적으로 남조류의 과잉성장에 영향을 미치는 요소는 높은 영양염류(질소, 인)와 유기물 농도, 고온과 안정적인 성층강도, 그리고 남조류의 생리적 특성 등으로 매우 다양하기 때문에 정확한 발생 원인의 분석이 어려운 경우가 많다. 그러나, 보에 의해 흐름이 조절되는 하천에서는 유량, 유속 및 수온성층 등이 남조류 성장과 천이특성에 가장 민감한 영향을 미친다. 선행 연구사례에서는 유량과 남조류 생체량이 서로 반비례 관계를 가진다는 점과 상 하층간의 온도차(수온성층)가 남조류 우점과 밀접한 관련이 있다는 것을 보였다(Sherman et al. 1998). 따라서 최근 국내에서도 보의 관리수위를 낮추어 유속을 증가시키고 체류시간을 감소시켜 녹조문제를 완화하려는 노력이 추진 중이다. 하지만 하천의 수질은 물리적, 화학적, 생물학적 요인들의 복잡한 상호작용의 결과이므로, 단기간의 측정 결과로 보 수위 저하의 효과를 평가하는데 어려움이 있다. 따라서 이를 과학적으로 평가하기 위해서 수리 수질 생태의 연동해석이 가능한 수치모델을 활용할 필요가 있다. 수치모델은 매개변수를 충분히 보정한다면, 다른 모든 요인은 동일한 조건에서 보 수위 저하만의 영향을 예측하는데 활용가능하다. 본 연구의 목적은 낙동강 수계 중류에 위치한 칠곡보-강정고령보 구간을 대상으로 3차원 수리 수질모델인 EFDC를 구축하고, 실측 자료를 이용하여 모델을 보정한 후 보 관리수위의 저하운영 시나리오에 따른 수질과 남조류의 시 공간적 변동 특성을 분석하는데 있다.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.2
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• pp.113-118
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• 2014

So many nationwide drinking water treatment plants are under much difficulties by new reinforced discharged effluent standards. Generally, the sludge at thickener should be retended for a long time during usual days. Sometime, the soluble manganese and chloroform may be formed under the anaerobic condition in the sludge thickener when the sludge retention time is longer with low turbidity. This phenomenon results in difficulties to keep regulatory level of the discharged effluent. It was necessary to improve the operation conditions and process itself in order to meet water quality standard recently reinforced. For an effort to overcome the problems, a sludge aeration was successfully implemented into the thickening process. Sludge aeration prevent particle oxidated Manganese eluting soluble de-oxidated Manganese, excrete formated Chloroform from effluent to air, and improve sludge settling through homogenized sludge particle. We aerated sludge at the conventional water treatment plant, measured Manganese and Chloroform of clarified water at upper sludge, and solid-fluid interface height of sludge in mass cylinder. As a result, contaminant's concentrations of the final effluent was much decreased : 41% of manganese, approximately 62% of chloroform and 35% of sludge volume, compared with non-aeration sludge.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.1
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• pp.42-48
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• 2012

In this study, experiment on phosphorus removal was performed by using microbubble liquid film flotation tank with microbubble module. After dissolving gas and liquid in dissolving tank, microbubble liquid film system created microbubbles in equal size under fixed low pressure. After being passed through $A_2O$ and m-$O_3$ process, secondary treatment wastewater was used as influent in phosphorus removal process. When the T-P concentration of influent was 2.89 mg/L, alum(8%, 30 mg/L) was injected into a microbubble flotation tank, the treatment resulted 94% of T-P removal rate. Remaining T-P concentration was less than 0.2 mg/L, which is in accord with the effluent quality standard. Seasonal variations in water temperature showed no differences in T-P removal property. When the inflow concentration of SS was 1.0 mg/L or more, it served as coagulation nuclei in the coagulation process. In that condition, average T-P removal rate was higher than 97%. When 50% of floated scum was returned, coagulator Al included in scum assisted the injected coagulator and maximized the coagulation efficiency of pollutant. In such treatment, the T-P concentration was measured as 0.18 mg/L and satisfied the outflow water quality standard, which is 0.2 mg/L or less.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.493-499
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• 2022

The standards pertaining to the quality of discharged water in sewage treatment plants are strengthening, and accordingly, facilities in sewage treatment plants are being upgraded. In addition, the discharge water quality of sewage treatment plants must be maintained at a high level, and efficient sewage treatment plant operations have thus emerged as a very important issue. For the efficient operation of sewage treatment plants, this study applied a basic blowing amount calculation method based on sewage facilities to evaluate the required oxygen amount and blowing amount according to inflow water quality by logicizing various influencing factors. As a result of calculating the amount of air blown by applying actual April water quality data from sewage treatment plant A to the blower demand calculation developed through this study, it was found that the average amount of air blown was reduced by about 12%. When the blower demand calculation developed here is applied to an actual sewage treatment plant, the amount of air blown can be controlled based on the inflow water quality. This can facilitate the realization of an autonomous control of sewage treatment plants, in contrast to the existing sewage treatment operation method that relies on operational experience of operator. In addition, it is expected that efficient sewage treatment plants can be operated by reducing blowing amounts and power costs, which will contribute to both energy and carbon savings.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.286-291
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• 2006

We studied possibility of mixing treatment of livestock wastewater and sewage using Phanerochaete chrysosporium PSBL-1. Our study showed that 97.6% of SS and 95% of T-P removal efficiency was achieved when 2 mL BF02(a coagulant) and 100 mL C-210EL(a cationic polymer) were added to the mixture(2:1, v/v) of livestock wastewater and sewage. We studied treatment characteristic of Phanerochaete chrysosporium PSBL-1, after were mixed pretreated wastewater and sewage by dillution ten times about livestock wastewater. The removal efficiency of NBDCOD(non-biodegradable COD), $NH_3-N$ and T-N was increased according to increase of pH. That is, T-N concentration of effluent was satisfied 60 mg/L by drain water waterqulity standard of livestock wastewater public treatment facilities with 35 mg/L from a lapse of five days at pH 6.7, 51 mg/L from a lapse of three days at pH 8 and 33 mg/L from a lapse of one day at pH 10. Moreover $COD_{Mn}$ concentration of effluent was satisfied 40 mg/L by drain water waterqulity standard of livestock wastewater public treatment facilities after a laps of one day at all pH. Organics and nitrogen concentrations of effluent were higher case with addition of V.A.(veratryl alcohol) than case without addition of V.A.(veratryl alcohol). $COD_{Mn}$ concentration of effluent satisfied drain water qulity standard of livestock wastewater public treatment facilities from a lapse of one day, when C/N rate(3:1) of influent was not controled. T-N satisfied that from a lapse of two days, when C/N rate was controled with $4{\sim}6$.

• Journal of Navigation and Port Research
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• v.32 no.8
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• pp.637-643
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• 2008

When planning outfall system, the first target cif design is to maximize initial dilution of discharge effluent. To achieve the target effectively, the characteristics of mixing phenomenon between ambient and discharged water should be analyzed. Especially the analysis at the Near-Field-Region(NFR) as initial dilution zone should be preceded. Usually, the initial behavior of effluent through outfall system is rising toward the surface due to mixing with ambient water for heat discharge and sinking toward the bottom due to the difference of density for brine discharge. After mixed with eddies accompanied by the ambient water, the plumes are showing the same density and internal current pattern by advection and diffusion. Until recently, lots of studies are being carried out for the optimum design of outfall system. but it is difficult to find any studies of heat and brine discharge at the same time. Therefore, this study is hoped to provide some basic data for optimum design of outfall system.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.11-18
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• 2010

The contamination of a suite of heavy metals were evaluated in water and sediments of urban stream, Tancheon down the stream. Tancheon is a urban stream which goes all the way across the urban area where various pollution sources are present. The sixteen study sites from seven different areas were designated down the stream. The heavy metal levels of the streams were detected in the order of Zn>Cu>Ni>Pb>Cd>Cr>Sb. There was a difference in the relative order of the concentration ranking in lake sediments. There is a trend that the heavy metal levels are higher at the sites where the construction causes inflow of soil particles to stream. Toxicity tests using pore-water in sediments were conducted for samples collected in some study sites, and pore-water in one site was proven to be toxic to Japanes medaka (Oryzias latipes). The reason may be the fecal pollution rather than heavy metal effect. Strong odor was detected in the sediment whose pore-water samples showed ecotoxicity. We did not observed the increasing concentration of heavy metals down to stream since the soil texture varied in the stream area of our study. Further study is needed to find quantitative relations between the level of contamination and its eco-effect.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.153-158
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• 2004

The numerous investments have been introduced to design and assess mixing zone characteristics of wastewater discharges to the ocean. Specially It strive to meet water quality standard for persistent and bio-accumulative chemical contaminants at the point of discharge through continual improvement pollution prevention measures and other voluntary measures in the developed country. The goals that of this paper are to emphasize the regulatory mixing zone is defined as an allocated impact zone where the numeric water quality criteria may be exceeded as long as acutely toxic conditions are prevent. Furthermore, mixing zones be limited to an area or volume as small as practicable that with not interfere with the designated uses or the established community of aquatic life in the segment for which the uses are designated and the shape be a simple configuration that is easy to locate in the body of water and avoids impingement on biologically important areas and the shore hugging plumes should be avoided This results should be used with caution in evaluation the mixing zone characteristics of a discharge and only in conjunction with information from the effective marine outfall design as well as for the sound harbour design. Thus the numerical investigation using CORMIX has been performed to show the regulatory mixing zone in the near and far field of the marine outfall.