• Membrane and Water Treatment
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• 제8권5호
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• pp.395-409
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• 2017

Membrane bioreactor (MBR) is a compact and efficient wastewater treatment and reclamation technology; but, it is limited by membrane fouling. The control of membrane fouling significantly increases operational and maintenance costs. Bacteria and their byproducts - extracellular polymeric substances (EPS) - are major contributors to membrane fouling in MBRs. A recent attempt at fouling mitigation is the development of aerobic granular sludge membrane bioreactor (AGMBR) through the integration of a novel biotechnology - aerobic granulation - and MBR. This paper provides an overview on the development of AGMBR to mitigate membrane fouling caused by bacteria and EPS. In AGMBR, EPS are used up in granule formation; and, the rigid structure of granules provides a surface for bacteria to attach to rather than the membrane surface. Preliminary research on AGMBR using synthetic wastewater show remarkable membrane fouling reduction compared to conventional MBR, thus improved membrane filtration. Enhanced performance in AGMBR using actual municipal wastewater at pilot-scale has also been reported. Therefore, further research is needed to determine AGMBR optimal operational conditions to enhance granule stability in long-term operations and in full-scale applications.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2012년도 전기공동학술대회 논문집
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• pp.188-190
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• 2012

고전단력을 갖도록 개발된 Homogenizer를 이용해 IFO 380cst Bunker-C 시료를 미립화 및 균질화하는 전처리를 시행하였다. 전처리된 시료의 슬러지 저감효과를 확인하기위하여 유청정기(oil purifier)를 이용하였고, 실험결과 약 13% 가량 슬러지 생성이 감소하는 것을 확인하였다. 또한, 전처리 후 유청정기를 통과한 시료를 실제 보일러 시스템에서 연소시켜 연소 성능 특성을 확인한 결과 CO가 감소하는 경향을 확인하였다. 선박운항비용 분석을 통해 U.L.C.C 기준 연 8,800만원 가량의 연료비 절감 효과가 있을 것으로 추정된다.

• Environmental Engineering Research
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• 제17권1호
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• pp.41-46
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• 2012

In this study, the performance of new digestion system (NDS) for the treatment of food waste leachate was evaluated. The food waste leachate was fed intermittently to an anaerobic reactor at increasing steps of 3.3 L/day (hydraulic retention time [HRT] = 30 day), 5 L/day (HRT = 20 day), and finally 10 L/day (HRT = 10 day). In the anaerobic reactor, the pH and alkalinity were maintained at 7.6 to 8.2 and 8,940-14,400 mg/L, respectively. Maximum methane yield determined to be 0.686L $CH_4$/g volatile solids (VS) containing HRT over 20 day. In the digester, 102,328 mg chemical oxygen demand (COD)/L was removed to produce 350 L/day (70% of the total) of biogas, but in the digested sludge reduction (DSR) unit, only 3,471 mg COD/L was removed with a biogas production of 158 L/day. Without adding any chemicals, 25% of total nitrogen (TN) and 31% of total phosphorus (TP) were removed after the DSR, while only 48% of TN and 32% of TP were removed in the nitrogen, phosphorus, and heavy metals (NPHM) removal unit. Total removal of TN was 73% and total removal of TP was 63%.

• 한국지하수토양환경학회지:지하수토양환경
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• 제10권3호
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• pp.52-63
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• 2005

근래 우리나라에는 음식물류 폐기물 등 유기성 폐기물과 관련하여 두 가지 주요한 정책이 추진되었다 하나는 1995 년에 전면 시행된 폐기물 종량제이고 또 하나는 폐기물관리법에 의한 유기성폐기물의 매립금지 조치이다. 이 두 정책의 시행으로 유기성폐기물의 발생원 감량과 퇴비화 및 사료화 등 재활용 기술의 발전이라는 긍정적인 효과를 거 두고 있으나 다른 한편으로는 법률적, 재활용의 하부구조, 기술적 측면에서 음식물류 폐기물 정책을 추진하는데 걸림돌로 작용하는 잠재된 문제점도 공존하고 있다. 본 연구에서는 음식물류 폐기물 자원화 정책의 문제점을 살펴보고 이에 대한 개선방안을 제시하고자 한다.

• 한국물환경학회지
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• 제20권6호
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• pp.664-669
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• 2004

An upflow BAF(Biological Aerated Filter) equipped with an expanded clay media was applied to reuse weaving wastewater of water jet loom. The performance of lab-scale biofilter was investigated by the adjustment of EBCTs(Empty Bed Contact Time) and the packing ratio of media, which were changed 1.1 to 3.7hr and 38 to 63%, respectively. In most conditions except 1.1hr of EBCT, BOD, CODcr, SS and Turbidity of the effluent were 1~4mg/L, 7~16mg/L, 1~5mg/L and 5~14NTU, where their removal efficiencies were 76~95%, 82~93%, 63~94% and 59~81%, respectively. From the observation of SEM(Scanning Electron Microscope) photographs of porous clay media, it was revealed that this media provided good performance of retaining microbes effectively. In addition, $0.44~0.49kgVSS/kgBOD_{rem}$. of low sludge reduction was expected. The most efficient back washing cycle and procedure were once per 4 to 9 days and air including collapse-pulsing method, respectively. Therefore, this system can be of use as an weaving wastewater treatment for reuse.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
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• pp.290-299
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• 2005

Two decommissioning projects are carried out at the KAERI (Korean Atomic Energy Research Institute), one for the Korea research reactors, KRR-1 and KRR-2, and another for the uranium conversion plant (UCP). The concept of the management of the wastes from the decommissioning sites was reviewed with a relation of the decommissioning strategies, technologies for the treatment and the decontamination, and the characteristics of waste. All the liquid waste generated from KRR-1 and KRR-2 decommissioning site is evaporated by a solar evaporation facility and all the liquid waste from the UCP is treated together with lagoon sludge waste. The solid wastes from the decommissioning sites are categorized into three groups; not contaminated, restricted releasable and radioactive waste. The not-contaminated waste will be reused and/or disposed at an industrial disposal site, and the releasable waste is stored for the future disposal at the KAERI. The radioactive waste is packed in containers, and will be stored at the decommissioning sites till they are sent to a national repository site. The reduction of the radioactive solid waste is one of the strategies for the decommissioning projects and could be achieved by the repeated decontamination. By the achievement of the minimization strategy, the amount of radioactive waste was reduced and the disposal cost will be reduced, but the cost for manpower, for direct materials and for administration was increased.

• 펄프종이기술
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• 제40권5호
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• pp.53-59
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• 2008

This study was carried out to investigate the effect of photocatalysis using $TiO_2$ and UV applied for the COD reduction of wastewater in linerboard mill. Trials were done to obtain the optimum addition amounts of $TiO_2$ and $H_2O_2$ to the wastewater and find an appropriate pH condition for photocatalysis on $TiO_2$ for degrading COD. The photocatalytic reaction was applied to the wastewater collected after secondary activated sludge treatment in WWTP of linerboard mill. The optimum application of photocatalysis reaction was obtained under the addition conditions of 2 g/L of $TiO_2$ and 200 mg/L of $H_2O_2$ at pH 3.0, respectively. The removal efficiency of $SCOD_{Cr}$ by photocatalytic treatment was 86.4 % and higher than Fenton treatment in which removal efficiency was 67.4 %. It was concluded that the photocatalytic process using $TiO_2$ and UV could be applied to the wastewater treatment in linerboard mill and also to the dramatic drop-off in NBDCOD load from wastewater of tertiary treatment in WWTP.

• 공업화학
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• 제7권4호
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• pp.614-622
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• 1996

엣칭용 염화제2철 용액중의 효과적인 니켈제거에 관해 연구하였다. 전해철괴 또는 폐새도우마스크 철편을 사용하여 염화제2철을 염화제1철로 환원시킨후 용액중의 $Ni^{2+}$를 전해철 분말로 환원 석출시켰다. 최적의 실험조건하에서 초기 니켈의 농도가 1.0%일 때 니켈제거율은 99%이었고 초기 니켈의 농도가 0.1%일 때 니켈제거율은 98%이었다. 염화제2철의 환원반응 중에 생성된 수산화철의 종류 및 입자크기를 XRD와 SEM으로 분석하였다.

• Journal of Microbiology and Biotechnology
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• 제6권1호
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• pp.30-35
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• 1996

Distillery wastewater was used in a thermophilic laboratory-scale two stage anaerobic digester to test the effects of the redox potential of the first acidogenic reactor on the performance of the system. The digester consisted of first a acidogenic reactor and the an upflow anaerobic sludge blanket (UASB) reactor. The digestor was operated at a hydraulic retention time (HRT) of 48 h. Under these conditions, about 90% of the chemical oxygen demand as measured by the chromate method ($COD_{cr}$) was removed with a gas production yield of 0.4 l/g-COD removed. The redox potential of the acidogenic reactor was increased when the reactor was purged with nitrogen gas or agitation speed was increased. The increase in reduction potential was accompanied by an increase in acetate production and a decrease in butyrate formation. A similar trend was observed when a small amount of air was introduced into the acidogenic reactor. It is believed that the hydrogen partial pressure in the acidogenic reactor was decreased by the above mentioned treatments. The possible failure of anaerobic digestion processes due to over-loading could be avoided by the above mentioned treatments.

• 한국압력기기공학회 논문집
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• 제7권3호
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• pp.8-14
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• 2011

The clogging of the flow area at the tube support plates(TSPs), especially at the upper TSPs results in the water level oscillation of a steam generator during normal operation. A reduction of the TSP flow area causes to increase in pressure drop within the two-phase flow zone, which destabilizes the boiling flow through the tube bundle. This phenomenon was occasionally observed at a few domestic and foreign nuclear power plants. One of the methods for defining the flow area clogging is visual inspection, which is the most effective inspection method. The results of the visual inspection for TSPs' flow area are clogging images on TSPs' quartrefoil lobes. These images are complexly distorted due to lens aberration and external factors like the distance to a subject and angle etc. In this work, we developed the analysis algorithm for clogging image of the TSP flow area of steam generators. For this purpose, we designed an image verification device applicable to the camera employed in the field for visual inspection and then, we demonstrated the validity of image analysis algorithm by using this device and commercial autoCAD program.