• 한국습지학회지
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• 제16권1호
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• pp.41-50
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• 2014

본 연구는 오염된 유수지 수질개선을 위한 고속 선회류 침전 장치(HRSC)의 이용 가능성을 평가하는데 목적을 두었다. 이를 위해 실험실 규모 및 파일럿 규모의 실험을 수행하였다. 또 전산유체역학(CFD) 프로그램 중 하나인 Fluent를 이용하여 유입속도 및 유입직경, 몸체길이($L_B$) 및 하부콘길이(Lc), 역경사콘 기울기 및 간격, 하부유출홀 설치 여부가 HRSC 장치내부의 유체흐름 패턴에 미치는 영향을 분석하였다. 유동 분석 결과와 실험실 규모의 실험 결과를 토대로 파일럿 장치를 제작하고 유수지 시료를 대상으로 현장 적용 가능성을 평가하였다. 장치 내부의 유동 조사 결과, 유입 유량과 직경 보다 유입 속도가 선회류 형성에 더 큰 영향을 나타내었으며, $L_B$ $1.2{\sim}1.6D_B$(몸체 직경), Lc $0.35{\sim}0.5L_B$ 범위에서는 큰 차이가 없었으나 $L_B/D_B$ 2.0, $Lc/L_B$ 0.75로 비가 큰 경우 선회류는 감소되었다. 역경사콘 기울기가 커질수록 역경사콘 내부 속도는 낮아지고 매우 균일하게 분포되었으며, 역경사콘 간격은 난류를 방지하기 위해 10cm가 20cm 보다 좋은 조건이었다. 하부 유출홀은 설치하지 않는 것이 배출수의 고른 유량 분배와 편류 방지를 위해 보다 좋은 것으로 판단되었다. 파일럿 규모의 현장 실험 결과 수중의 입자성 물질이 효과적으로 제거되어 본 장치가 유수지와 같은 대용량 수체의 수질개선을 위한 한 가지 방안으로 활용될 수 있을 것으로 기대되었다.

• 한국습지학회지
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• 제17권1호
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• pp.11-18
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• 2015

질소에 의한 수질 오염의 심각성이 부각되면서 하 폐수 내 질소제거를 위한 연구가 수행되고 있다. 특히 아질산화 반응을 기반으로 하는 경제적이며 친환경적인 장점을 지닌 혁신적인 질소 제거 공법에 관한 연구가 주목받고 있다. 하지만 아질산화 반응을 기반으로 하는 공법의 현장 적용성 및 효율화 방안에 관한 연구는 완전히 이루어지고 있지 않은 실정이다. 본 연구에서는 하수처리장 유입 하수, 최초 침전지 상등액, 반류수 그리고 가축분뇨의 특성분석 및 실험실 규모 반응조를 운전하였다. 반류수 및 가축분뇨의 경우 다른 하수에 비해 고농도의 질소를 함유한 것으로 나타나 수처리 계통 질소 부하를 증가시키는 것으로 나타났다. 반응조 운전 결과 낮은 암모니아성 질소의 농도로 인해 유입 하수와 최초 침전지 상등액의 경우에는 아질산화 반응이 유도되지 않음을 확인하였다. 또한 하수 종류 별로 아질산화 반응이 유도되는 체류시간 조건이 차이를 보였는데 이는 유기물 및 암모니아성 질소 농도에 의한 것으로 판단된다. 아질산화 반응이 유도된 하수 중 혐기 소화 상등액이 가장 높은 효율을 보이는 것으로 나타났다.

• 상하수도학회지
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• 제26권2호
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• pp.265-273
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• 2012

Anaerobic sewage treatment is drawing attentions due to high energy consumptions and sludge production associated with aerobic treatment. This study evaluates the treatment characteristics and energy balance of a fluidized bed reactor (FBR) for treating domestic sewage at $20^{\circ}C{\sim}25^{\circ}C$ for 245 days. Sewage fed to the FBR was a primary clarifier effluent of a domestic sewage treatment plant with COD of 99-301 mg/L and $BOD_{5}$ of 37-149 mg/L. Effluent $SBOD_{5}$ and its removal efficiency at HRT of 1~3 h were 6~15 mg/L and 73.4~85.5%, respectively, achieving high removal efficiency for soluble organic substances even at short HRTs. COD removal efficiency and its effluent concentration were 53.8~75.9% and 51~83 mg/L, respectively. The energy production potential from gaseous methane was 0.009-0.028 kWh/$m^{3}$, which satisfies the energy required for the FBR operation.

• 대한토목학회논문집
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• 제8권1호
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• pp.69-75
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• 1988

활성 슬러지 하수처리장의 주요 Process Control Variables인 Sludge age와 Sludge recycle올 고려하여 폐슬러지의 유량 ($Q_w$)을 효과적으로 결정하기 위한 두가지의 식이 개발되었다. 아울러 반송 슬러지의 일부를 폐슬러지로 배출할 경우에는 우선 순환비 (R)를, 포기조내의 활성슬러지의 일부를 폐슬러지로 배출할 경우에는 2차침전지의 슬러지 침전효율($S_f$)을 정확히 측정하여 개발된 식을 이용하면 폐슬러지의 유량을 용이하게 산정할 수 있다는 사실이 Sensitivity analysis의 결과로 밝혀졌다.

• Environmental Engineering Research
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• 제22권4호
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• pp.377-383
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• 2017

A tube-type ceramic membrane for microfiltration was developed, and the membrane module comprised of three membranes was also applied to biological carbon and nitrogen removal processes for post-treatment. Manufacturing the microfiltration membrane was successful with the structure and boundary of the coated and support layers within the membrane module clearly observable. Total kjeldahl nitrogen removal from effluent was additionally achieved through the elimination of solids containing organic nitrogen by use of the ceramic membrane module. Removal of suspended solids and colloidal substances were noticeably improved after membrane filtration, and the filtration function of the ceramic membrane could also easily be recovered by physical cleaning. By using the ceramic membrane module, the system showed average removals of organics, nitrogen, and solids up to 98%, 80% and 99.9%, respectively. Thus, this microfiltration system appears to be an alternative and flexible option for existing biological nutrient removal processes suffering from poor settling performance due to the use of a clarifier.

• 멤브레인
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• 제1권1호
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• pp.78-95
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• 1991

미국 캘리포니아주 Orange County에 위치한 Water Factory 21(WF-21)은 생물학적 처리공정을 거친 도시하수를 재생하여, 이 재생수를 지하수지층으로 유입되는 해수의 침투를 막기 위한 Reinjection System에 이용하고 있다. 장치 구성 공정은 Lime처리, Air Stripping, 사여과, 활성탄처리, 역삼투막 및 염소처리 등으로 이루어지며, 이에 대한 각 처리공정의 효율성에 대하여 실험을 실시하였다. 3년간의 장기간에 걸친 실험결과로부터, 도시하수에 대한 RO Membrane 처리수는 음료 수질 기준에 적합한 고수질의 물을 생성할 수 있음을 입증했다. Pilot Plant 실험에선 Lime Clarifier만으로 전처리를 실시하여 성공적인 결과를 얻었으며, 또한 저압 (250 psi)이 적용된 새로운 Membrane을 사용하여 에너지 절약을 통한 비용 절감 효과에 대한 실험도 상당한 가능성을 보여주었다.

• 멤브레인
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• 제1권1호
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• pp.100-100
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• 1991

A novel system to thicken the concentrated colloidal solution from membrane water treat-ment processes was developed. A hollow-fiber microfilter(hydrophilic polyethylene nominal pore size 0.1 μm total surface area 0.42 m2) was installed in an acrylic housing that has an aeration port 5 cm below the membrane and a clarifier in the bottom. The concentrate was uniformly supplied from the top of the housing. Bacuum filtration caused downward flow of concentrate and as a result thickening interface. The addition of poly-aluminum chloride (PAC) resulted in rapid increase of trans-membrane pressure (TMP) and in no improvement of the filtered water turbidity and thickening process. Two types of con-centrate and concentrate turbidity had little effect on the increase of TMP and concentrate thickening. It was observed that for the same height of membrane housing membrane surface area to housing volume (A/V) ratio had significant effect on the increase of TMP. When the housing volume was increased ten times the increasing rate of TMP was three times faster as compared to the original housing. A hydraulic model successfully simulated the formation and sedimentation of thickening interface.

• Carbon letters
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• 제15권3호
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• pp.203-209
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• 2014

The adsorption of volatile organic compounds (VOCs) was carried out using an activated carbon fiber (ACF) filter in an automobile. The adsorption capacities of formaldehyde, toluene, and benzene on an ACF filter were far better than those of a polypropylene (PP) mat filter and combined (PP+activated carbon) mat filter by batch adsorption in a gas bag. In a continuous flow of air containing toluene vapor through an ACF packed bed, the breakpoint time was very long, the length of the unused bed was short, and sharp "S" -type breakthrough curve was plotted soon after breakpoint, showing a narrow mass transfer zone of toluene on the ACF. The adsorption amount of toluene on the ACF filter was proportional to the specific surface area of the ACF; however, the development of mesopores 2-5 nm in size on the ACF was very effective with regard to the adsorption of toluene. The ACF air clarifier filter is strongly recommended to remove VOCs in newly produced automobiles.

• 한국환경과학회지
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• 제22권10호
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• pp.1353-1361
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• 2013

The objectives of this paper are the characterization of the pretreatment of wastewater by microfiltration (MF) membranes for river maintenance and water recycling. This is done by investigation of the proper coagulation conditions, such as the types and doses of coagulants, mixing conditions (velocity gradients and mixing periods), pH, etc., using jar tests. The effluent water from a pore control fiber (PCF) filter located after the secondary clarifier at Kang-byeon Sewage Treatment Plant (K-STP) was used in these experiments. Two established coagulants, aluminum sulfate (Alum) and poly aluminum chloride (PAC), which are commonly used in sewage treatment plants to treat drinking water, were used in this research. The results indicate that the optimal coagulation velocity gradients (G) and agitation period (T) for both Alum and PAC were 200-250 $s^{-1}$ and 5 min respectively, but the coagulation efficiencies for both Alum and PAC were lower at low values of G and T. For a 60 min filtration period on the MF, the flux efficiencies ($J/J_0$ (%)) at the K-STP effluent that were coagulated by PAC and Alum were 92.9 % and 79.9 %, respectively, under the same coagulation conditions. It is concluded that an enhanced membrane process is possible by effective filtration of effluent at the K-STP using the coagulation-membrane separation process.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1995년도 추계 학술대회논문집
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• pp.160-168
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• 1995

This paper describes computational efforts on the various energy and environmental problems using Patankar's SIMPLE method. The specific problems included in this study are : pollutant and flammable material dispersions in open and confined areas, aerator-induced flow in a lake for DO(dissolved oxygen) concentration, primary clarifier for water and waste water treatment, hood ventilation in workplace, cyclone and LNG combustors and Dow chlorination reactor. A control-volume based finite-difference method is employed together with the power-law scheme. The pressure-velocity coupling is resolved by the use of the revised version of SIMPLE, says SIMPLER and SIMPLEC. The Reynolds stresses are closed using the standard or the RNG $k-{\varepsilon}$ models. Turbulent reaction is modeled using two fast chemistry methods such as eddy breakup and conserved scalar models. Further, a nonequilibrium model is developed for the application of the chlorination process in the Dow reactor. Other important empirical models and physical insights appeared in this study are presented and discussed in a brief note. The computational method developed in this study is considered, in general, as a viable tool for the design and determination of the optimal condition of various engineering system of interest.