• 한국지반환경공학회 논문집
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• 제11권8호
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• pp.57-63
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• 2010

본 연구에서는 준설투기장의 설계를 위하여 실내시험으로 컬럼을 이용한 준설토 침강 자중압밀시험 및 상등수에 대한 부유물 농도시험을 수행하였으며, 현장조건과 배출수의 부유물 농도를 고려한 준설투기장을 설계 검토하였다. 준설투기장 폭과 목표 부유물 농도와의 관계 검토결과, 소요면적에서는 투기장 폭이 좁고 길이가 길수록 부유물 농도가 감소함을 알 수 있었다. 또한 준설투기가 진행됨에 따라 배출되는 상등수의 부유물 농도의 변화를 예측하기 위하여 침강허용깊이의 변화에 대한 영향도 고려되어야 하며, 이는 배출수의 목표 부유물 농도가 낮을수록 더욱 중요하다.

• 한국지반환경공학회 논문집
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• 제12권6호
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• pp.35-42
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• 2011

본 논문에서는 준설매립투기장에서 발생하는 부유물질의 유출농도를 예측하기 위하여 실내모형실험을 수행하고 실험결과를 기존의 설계방법에서 제시한 결과와 비교 분석하였다. 현장의 펌프준설선에 의한 준설토의 투기 상황을 모사하기 위하여 투기농도와 투기장의 길이를 변화시킨 실내 모형실험을 수행하고, 투기가 진행됨에 따른 부유물질 유출 농도의 시간에 따른 변화를 측정하였다. 컬럼을 사용한 침강압밀 실험결과를 바탕으로 한 미공병단(US Army COE, 1987)에서 제시한 설계방법에 의한 유출농도에 대한 분석결과와 모형실험 결과를 비교한 결과, 상호 유사한 경향을 나타냄을 확인하였다.

• Fisheries and Aquatic Sciences
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• 제13권2호
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• pp.133-139
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• 2010

The effects of suspended solids size on culture water quality were determined in a commercial recirculating aquaculture system (RAS) for Japanese eel, Anguilla japonica. The particulate phase of the culture water was serially divided into six size fractions using 300, 200, 100, 75, 45, and 26 ${\mu}m$ pore size stainless sieves. The total, dissolved, and particulate nitrogen and phosphorus, and suspended solids for each fraction were determined. The concentration ranges in the fractions were: total nitrogen, 164-148 mg $L^{-1}$; total phosphorus, 20.4-15.5 mg $L^{-1}$; and total suspended solids, 8.1-6.1 mg $L^{-1}$. The concentration of total nitrogen and total phosphorus decreased significantly (P<0.05) with a 26 ${\mu}m$ and 200 ${\mu}m$ filter pore size, respectively. Nutrients from dissolved organic substances were much higher than from particulates. Analysis of particle size fractionation and its effects on water quality is useful to estimate removal efficiencies of a commercial effluent screening device for solid management and development of solid removal systems.

• 상하수도학회지
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• 제26권1호
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• pp.107-113
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• 2012

Pollutants in aquaculture system effluent mostly originated from solid wastes including uneaten feed and excreta of cultured species. In this research, DAF(Dissolved Air Flotation) unit is suggested as an integrated solid control unit especially as a form of IIBG(Inline Injection Bubble Generation) process in aquaculture system. Solid removal performance of DAF unit was examined under various operation and salinity conditions with turbidity and suspended solid. Solid waste removal efficiencies were found to be affected by operation conditions including saturator pressure, recycle ratio, coagulant concentration. Solid removal efficiency was higher under higher saturator pressure and recycle ratio under which condition larger number of bubbles is generated. Coagulant is thought to have important role in creating bubble-particle aggregate by showing better removal efficiency with higher concentration. However higher saline water showed less effectiveness in removing solids by DAF(IIBG). Application of DAF(IIBG) process also showed additional effect in phosphate removal and DO(Dissolved Oxygen) supply. Phosphate existed in polluted water was removed up to 46% after treatment, which is thought to attribute to aluminium phosphate precipitation. And DO concentration was found to increase over 50% of initial saturation concentration after the injection of micro-bubbles. Through experiments on solid removal from aquaculture effluent, DAF(IIBG) process is estimated to be effective solid control method. This property can help aquaculture system being installed and operated simply and effectively.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권7호
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• pp.54-62
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• 2013

Fine suspended solids and soluble heavy metals generated from mine drainage could destroy environment as the aesthetic landscapes, and depreciate water quality. Therefore, this research is focused on process development applied the actual field for controlling fine suspended solids and heavy metals, and so that bench-scale tests were performed for field application based on advanced researches. The field of mine drainage in this research was in H mine located Taebaek-si, Gangwon-do. The inclination plates were mounted 2 kinds of arrangement (octagon and radial types) in circle type settling basin. The inclination plates could be helped to settle of suspended solids; decreased 34% of suspended solids and 50% of turbidity in effluent. Radial type of inclination plates showed the results that is more efficient to settle of suspended solids (average to 3.45 mg/L) compared to octagon type. In the experiments to decrease retention time of mine drainage in settling basin from 6 hrs to 1.5 hrs, suspended solid concentration was exceeded to 30 mg/L as the standard for suspended solid at 10 days after the operation under tha retention time of 3hrs and 1.5hrs. In the tests for filtration, granular activated carbons were indicated the better effective to filtering and absorption of fine suspended solid and soluble heavy metals than anthracite.

• 한국지반환경공학회 논문집
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• 제11권8호
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• pp.25-32
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• 2010

석유계 탄화수소 화합물로 인한 토양과 지하수 오염은 환경과 건강에 영향을 미치는 주된 원인으로 제기되어 왔다. 이러한 오염물질들은 흡착포, 활성탄 또는 중력 방식의 유수분리 장치 등을 이용하여 처리하고 있다. 하지만 이러한 경우 자유상 유류(free product)로 존재하는 경우에는 효과적이나 에멀젼 상태의 유류는 제거할 수 없는 것으로 알려져 있다. 따라서 본 연구에서는 굴착시 예상되는 지하수의 고농도 현탁성 고형물로 인한 지하수 처리시 문제점과 TPH(Total Petroleum Hydrocarbon)를 어떻게 효율적으로 제거할 수 있는지 방안을 제시하고자 한다. 고분자 폴리머를 사용하여 혼화 응집 실험을 수행한 결과 5분 이내에 SS(Suspended Solids)와 COD(Chemical Oxygen Demand) 농도가 지하수 수질 기준을 만족하는 것을 나타났으나, TPH 농도는 방류수 수질 기준을 만족하지 못하는 것으로 나타났다. DAF(Dissolved Air Flotation) 실험 결과 단일 DAF 공정으로는 방류수 수질 기준을 만족하지는 못하였다. 단일 DAF 반응조를 이용하여 DAF와 혼화 응집 반응을 동시에 수행하는 경우 20분에 모든 기준을 만족하는 것으로 나타났다.

• 한국수산과학회지
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• 제40권2호
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• pp.73-78
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• 2007

The suitability of a flexible fiber filter for removing suspended solid (SS) in a recirculating aquaculture system was evaluated. This study focused on variation in the performance with a change in filtering time, influent water quality, and filtering mode duration. The particle distribution diagram of the filter effluent showed that the number of particles bigger than $5-8{\mu}m$ decreased dramatically, and the removal efficiency exceeded 80%. Although the removal efficiencies of SS and chemical oxygen demand (COD) were dependent on the quality of the influent, the SS and COD concentrations of the effluent were not affected by the influent concentrations. This was despite the deterioration if water quality after feeding in the rearing tank. The performance of the filter was not affected by the filtering mode duration, feeding conditions, or filtering time. The SS concentration and turbidity of the recirculating-type rearing tank were 30% and 50% lower, respectively, than of the a non-recirculating-type rearing tank under the same operating conditions. The flexible fiber filter was applicable to a recirculating aquaculture system that uses plenty of seawater, based on its low filtering resistance $(2kg_f/cm^2)$, high flux $(330m^3/m^2/hr)$, and high fine particle removal efficiency (80%, $5-8{\mu}m$).

• 한국환경과학회지
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• 제31권4호
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• pp.295-309
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• 2022

The purpose of this study was to evaluate the operational characteristics of wastewater treatment using Sequencing Batch Reactor (SBR) with Aerobic Granular Sludge (AGS) separator in the pilot plant. Pilot plant experiments were conducted using SBR with AGS separator and pollution removal efficiencies were evaluated based on the operational condition and surface properties of AGS. The results of the operation on water quality of the effluent showed that the average concentration of total organic carbon, suspended solids, nitrogen, and phosphorus was 6.89 mg/L, 7.33 mg/L, 7.33 mg/L, and 0.2 mg/L, respectively. All these concentrations complied the effluent standard in Korea. The concentration of mixed liquor suspended solid (MLSS) fluctuated, but the AGS/MLSS ratio was constant at 86.5±1.3%. Although the AGS/MLSS ratio was constant, sludge volume index improved. These results suggested that the particle discharged fine sludge and increased the AGS praticle size in the AGS. Optical microscopy revealed the presence of dense AGS at the end of the operation, and particles of > 0.6 mm were found. Compared to those of belt-type AGS separator, the required area and power consumption of the hydrocyclone-type AGS separator were reduced by 27.5% and 83.8%, respectively.

• 상하수도학회지
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• 제24권2호
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• pp.219-230
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• 2010

Computer simulation has been widely used to design and optimize the operation of wastewater treatment plants since 1980. For secondary clarifiers, the simulation has been a tool to optimize the performance by providing dimensions for flocculation well. However, there has been no attempt to find the optimized geometrical parameters in circular secondary clarifier using simulation tools. In this study, three SVIs (Sludge Volume Indexes), two well types (feed and flocculation wells), 8 SWDs (Side Water Depths) and 9 bottom slopes were variables for simulation. Diurnal inflow and associated MLSS (Mixed Liquor Suspended Solid) concentrations were used for input loadings. When flocculation well was installed, 48% less concentration at lowest ESS (Effluent Suspended Solid) concentrations was produced and the diurnal ESS concentration range had been reduced by 52%. From these results, flocculation well must be installed to produce lower and stable ESS from circular secondary clarifiers. Under same loading conditions with $300m{\ell}$/g of SVI, The lowest ESS was produced when SWD was 4.5m with 4% of bottom slope. Therefore, SWD and bottom slope must not be deeper than 4.5m and must be near 4%, respectively, in circular clarifier with flocculation well to produce the lowest ESS concentration.

• 상하수도학회지
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• 제38권3호
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• pp.165-175
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• 2024

The dissolved air at the bottom layer of the deep aeration tank transforms into fine gas bubbles within the MLSS (Mixed Liquor Suspended Solid) floc when exposed to the atmosphere. MLSS floc flotation occurs when MLSS from the deep aeration tank enters the secondary clarifier for solid-liquid separation, as dissolved air becomes fine air within the MLSS floc. The floated MLSS floc causes a high SS (Suspended Solid) concentration in the secondary effluent. The fine air bubbles within the MLSS floc must be removed to achieve stable sedimentation in the secondary clarifier. Fine bubbles within the MLSS floc can be removed by air sparging. The settleability of MLSS was measured by sludge volume indexes (SVIs) after air sparging MLSS taken at the end of the deep aeration tank. MLSS settling tests were performed at MLSS heights of 200, 300, 400, and 500 mm, and compressed air was fed at the bottom of the settling column with air flow rates of 100, 300, and 500 ml/min at each MLSS height, respectively. Also, at each height and air flow rate, air was sparged for 3, 5, and 7 minutes, respectively. SVI was determined for each height, air flow rate, and sparging time, respectively. Experimental results showed that a 300 mm MLSS height, 300 ml/min air flow rate, and 3 minutes of sparging time were the least conditions to achieve less than 120 ml/g of SVI, which was the criterion for good MLSS settling in the secondary clarifier.