To raise the physical strength of alginate beads, this study manufactured alginate-cellulose bead by adding cellulose to alginate, and wanted to identify whether falginate-cellulose beads were sufficiently efficient in removing heavy metals. To find out optimal amounts of alginate and cellulose injection, this study conducted a pilot study, and repeated experiments proved that alginate 2 w/v% + cellulose 1 w/v% were the optimal amounts in manufacturing beads. Using micro materials tester, this study compared strengths of alginate beads and alginate-cellulose beads. Choosing Cd2+, Pb2+, and Ni2+ as materials to be removed, this study analyzed concentrations of them before and after the treatment. Experiments showed that, compared with alginate beads, the strength of alginate-cellulose beads was 2.26 times stronger, and that the latter could remove 98.22%, 99.99%, and 92.57% of Cd2+, Pb2+, Ni2+, respectively. While addition of cellulose to alginate made the absorption rate drop by about 1%, the beads were still highly efficient in removing heavy metals. Accordingly, it seems that alginate-cellulose beads can be used in removing heavy metals.

In this study, the removal efficiency of PFCs(perfluorinated compounds) in the GAC(granule activated carbon) process based on the superheated steam automatic regeneration system was investigated in laboratory scale and pilot-scale reactor. Among PFCs, PFHxS(perfluorohexyl sulfonate) was most effectively removed. The removal efficiency of PFCs was found to be closely related to the EBCT, and the removal efficiencies of PFOA(perfluorooctanoic acid), PFOS(perfluorooctyl sulfonate), and PFHxS were 43.7, 75, and 100%, respectively, under the condition of EBCT of 6 min. Afterward, PFOA, PFOS, and PFHxS exhibited the earlier breakthrough time in the order. After that, GAC was regenerated, and the removal efficiency of the PFCs before and after regeneration was compared. As a result, it was shown that the PFCs removal efficiency in the regenerated GAC process were higher, and that of PFOA was improved to 75%. The findings of this study indicate the feasibility of the superheated steam automatic regeneration system for the stable removal of the PFCs, and it was verified that this technology can be applied stably enough even in field conditions.

Copper oxide thin films are deposited using an ultrasonic-assisted spray pyrolysis deposition (SPD) system. To investigate the effect of substrate temperature and incorporation of a chelating agent on the growth of copper oxide thin films, the structural and optical properites of the copper oxide thin films are analyzed by X-ray diffraction (XRD), field-emssion scanning electron microscopy (FE-SEM), and UV-Vis spectrophotometry. At a temperature of less than 350 ℃, threedimensional structures consisting of cube-shaped Cu2O are formed, while spherical small particles of the CuO phase are formed at a temperature higher than 400 ℃ due to a Volmer-Weber growth mode on the silicon substrate. As a chelating agent was added to the source solutions, two-dimensional Cu2O thin films are preferentially deposited at a temperature less than 300 ℃, and the CuO thin film is formed even at a temperature less than 350 ℃. Therefore the structure and crystalline phase of the copper oxide is shown to be controllable.

Li-incorporated ZnO thin films were deposited by using ultrasonic-assisted spray pyrolysis deposition (SPD) system. To investigate the effect of Li-incorporation on the performance of ZnO thin films, the structural, electrical, and optical properites of the ZnO thin films were analyzed by means of X-ray diffraction (XRD), field-emssion scanning electron microscopy (FE-SEM), Hall effect measurement, and UV-Vis spectrophotometry with variation of the Li concentraion in the ZnO sources. Without incorporation of Li element, the ZnO surface showed large spiral domains. As the Li content increases, the size of spiral domains decreased gradually, and finally formed mixed small grain and one-dimensional nanorod-like structures on the surface. This morphological evolution was explained based on an anti-surfactant effect of Li atoms on the ZnO growth surface. In addition, the Li-incorporation changed the optical and electrical properties of the ZnO thin films by modifying the crystalline defect structures by doping effects.

Desalination plants have been recently constructed in many parts of the world due to water scarcity caused by population growth, industrialization and climate change. Most seawater desalination plants are designed with a submarine pipeline for intake and discharge. Submarine pipelines are installed directly on the bottom of the water body if the bottom is sandy and flat. Intake is located on a low-energy shoreline with minimal exposure to beach erosion, heavy storms, typhoons, tsunamis, or strong underwater currents. Typically, HDPE (High Density Polyethylene) pipes are used in such a configuration. Submarine pipelines cause many problems when they are not properly designed; HDPE pipelines can be floated or exposed to strong currents and wind or tidal action. This study examines the optimal design method for the trench depth of pipeline, analysis of on-bottom stability and dilution of the concentrate based on the desalination plant conducted at the Pacific coast of Peru, Chilca. As a result of this study, the submarine pipeline should be trenched at least below 1.8 m. The same direction of pipeline with the main wind is a key factor to achieve economic stability. The concentrate should be discharged as much as high position to yield high dilution rate.

We investigated a Leidenfrost effect in the growth of ZnO nanostructures on silicon substrates by ultrasonic-assisted spray pyrolysis deposition(SPD). Structural and optical properties of the ZnO nanostructures grown by varying the growth parameters, such as substrate temperature, source concentration, and suction rate of the mist in the chambers, were investigated using field-emission scanning electron microscopy, X-ray diffraction, and photoluminescence spectrum analysis. Structural investigations of the ZnO nanostructures showed abnormal evolution of the morphologies with variation of the substrate temperatures. The shape of the ZnO nanostructures transformed from nanoplate, nanorod, nanopencil, and nanoprism shapes with increasing of the substrate temperature from 250 to 450 °C; these shapes were significantly different from those seen for the conventional growth mechanisms in SPD. The observed growth behavior showed that a Leidenfrost effect dominantly affected the growth mechanism of the ZnO nanostructures.

We investigated the effect of ZnO buffer layer on the formation of ZnO thin film by ultrasonic assisted spray pyrolysis deposition. ZnO buffer layer was formed by wet solution method, which was repeated several times. Structural and optical properties of the ZnO thin films deposited on the ZnO buffer layers with various cycles and at various temperatures were investigated by field-emission scanning electron microscopy, X-ray diffraction, and photoluminescence spectrum analysis. The structural investigations showed that three-dimensional island shaped ZnO was formed on the bare Si substrate without buffer layers, while two-dimensional ZnO thin film was deposited on the ZnO buffer layers. In addition, structural and optical investigations showed that the crystalline quality of ZnO thin film was improved by introducing the buffer layers. This improvement was attributed to the modulation of the surface energy of the Si surface by the ZnO buffer layer, which finally resulted in a modification of the growth mode from three to two-dimensional.

The need of reusing sewage sludge is highly increasing as the amount of domestic sewage sludge is growing and sewage management strategies were reinforced. Accordingly, in this research, we studied the composting possibility of sludge in sewage treatment plant J, using dryer facility with indirect system by conducting component analysis of dried sludge and experiment on cultivating crops. It was observed from the component analysis, that the dried sludge is appropriate for both decomposed manure standard of Ministry of Environment and fertilizer standard of Rural Development Administration. Besides, in the experiment on cultivating lettuce, the experimental group(soil + dried sludge) was superior to the control group(soil + bed soil) in apparent condition of leaves tensity and damage by disease and pest. In case of cultivating tomato, the experimental group showed stronger durability of fruits dangling on stems compared to the control group after 9 weeks. Consequently, the excess sludge dried by indirect heating system in the sewage treatment plant J is appropriate for the standard of both Ministry of Environment and Rural Development Administration and show good result in experiment on cultivating crops therefore it can be reused for composting.

본 연구에서는 시화호의 수질 관리 정책 연구를 위한 최근의 수질 자료 확보를 목적으로 2010년에 시화호 내 외측 해역에서 수질 조사를 수행하였다. 시화호 표층수 수질항목들의 수평적 농도분포는 하천을 통한 담수 유업과 배수갑문을 통한 외해수 유입의 영향으로 인하여 반윌 및 시화 산단 얀근 상류지역에서는 높고 배수갑문으로 갈수록 낮아지는 경향을 나타냈다. 시화호 외해에서는 TN 및 TP가 소래포구에 가까운 곳에서 높은 농도를 나타내었으며, 전체적으로 시화호 내해보다는 상대적으로 낮은 농도를 나타내었다. 시화호 내측의 경우, 여름철 성층 형성 및 저층의 활발한 유기물 분해로 빈산소층이 발달되고 있었다. 수질항목들의 수직적 농도분포의 경우, 용존영양염, TN 및 TP는 표층보다 저층에서 높았지만, COD, 클로로필-a 및 POC는 이와 반대로 저층보다 표층에서 높은 분포를 나타냈다. 시화호 표층수에서 염분은 용존영양염과 양호한 음의 상관성을 보여 담수 기원의 영양염 공급이 확인되었고, 이에 의한 식물플랑크톤의 대증식으로 COD 및 POC가 높게 나타났다.

고상 반응법을 이용하여 L a0.6S r0.4 Co0.2F e0.8 O3-delta/ 및 L a0.7S r0.3G a0.6F e0.4 O3-delta/ 분말을 합성하고 혼합전도체 분리막을 소결하여 제조하였다. 제조된 분리막들은 정확한 페롭스카이트 결정구조를 나타내었으며, 95% 이상의 높은 상대밀도를 나타내었다. 산소이온 변환 능력을 향상시키기 위해 L a0.7S r0.3G a0.6F e0.4 O3-delta/ disk의 양 표면에 L a0.6S r0.4Co O3-delta/ paste를 스크린 프린팅 방법으로 코팅하였으며 코팅 막은 비교적 치밀한 미세구조를 나타내었다. 코팅되지 않은 L a0.6S r0.4 Co0.2F e0.8 O3-delta/ 및 L a0.7S r0.3G a0.6F e0.4 O3-delta/ 분리막과 코팅된 L a0.7S r0.3G a0.6F e0.4 O3-delta/ 분리막의 산소투과 성능을 비교 실험한 결과, 900℃에서 L a0.6S r0.4 Co0.2F e0.8 O3-delta/ 분리막이 정상상태에서 0.266 mL/min.textrmcm2로 가장 많은 투과량을 보였으며 코팅된 L a0.7S r0.3G a0.6F e0.4 O3-delta/ 분리막의 정상상태 산소 투과 유속은 최고 0.19 mL/min.textrmcm2 정도로 코팅되지 않은 분리막에 비해 약 2~3배로 높게 나타났다.정도로 코팅되지 않은 분리막에 비해 약 2~3배로 높게 나타났다.코팅되지 않은 분리막에 비해 약 2~3배로 높게 나타났다. 높게 나타났다.

The amount of sewage treatment has been increasing year by year as the small and medium sized cities grow in Korea. Besides, the treatment of sludge has been more significant owing to the total ban on disposal of organic sludge in a landfill since April 2004 and ocean dumping of organic waste since December 2013. In this research, we studied the drying characteristics of sewage sludge by indirect heating device using thermal oil. The indirect heating device operated in a batch for 16 hours according to the variation of drying temperature between 100 and 200oC and the initial input weight of each type of sewage sludge was equally 60 kg. As a result, the moisture content in raw, excess and mixed sludge became lower than 10% under 14 hours at 160oC. The average water loss rate of raw, excess and mixed sludge is 0.436 g-wet/ min, 0.362 g-wet/min and 0.367 g-wet/min respectively at this stage. Therefore, the raw sludge can be dried well, using indirect heating device in sewage treatment plant. Also, it is better to dry raw sludge or excess sludge alone than mixed sludge because each type of sludge does not make synergistic effect but counter effect when they are together.

하수슬러지의 발생량은 해마다 증가하고 있으며 2011년 발생량은 310만톤에 다다르고 있다(환경부, 2012). 이처럼 수백만톤의 하수슬러지가 매년 발생하고 있지만 그에 대한 처리 기술력은 아직 부족한 것이 현실이며 발생슬러지 처리방법의 약 70%를 차지하는 해양배출은 런던협약에 의해 2013년 1월1일부터 전면 금지가 되었다. 이에 대해 대책으로 소각 및 재활용에 대한 비율을 높이고자 노력하고 있으며 특히 재활용 및 연료화 분야에 정부기관 및 다수의 연구기관에서 다양한 기술개발이 진행 중에 있다. 본 연구는 하수슬러지의 성상을 조사하고 파악함과 동시에 효과적인 슬러지 건조방법을 찾고자 함에 있다. 슬러지 건조방식은 크게 직접가온방식과 간접가온방식으로 분류할 수 있으며 이번 연구에서는 간접가온방식의 장점을 이용하여 슬러지 건조 특성에 대하여 알아보고자 하였다. 특히, 성상분석을 통하여 처리대상이 되는 하수슬러지를 파악하고 열매체유를 이용한 간접가온 방식의 슬러지 건조를 실시하였다. 열매체보일러를 통하여 운전온도를 조절하였으며 열원의 공급은 전기를 이용하는 방식을 사용하였다. 운전결과 180℃에서 운전시간이 12시간을 초과하면 슬러지의 함수율이 5%이하가 되며 수분변화율도 미비한 것으로 나타났다. 또한 운전시간이 8시간에서 10시간 사이에서 슬러지의 건조시 수분의 감소율이 약 20% 줄어드는 것으로 나타났다. 이는 슬러지의 수분이 낮아짐에 따라 수증기로 증발 시 발생되는 열손실량이 감소하여 슬러지 잠열이 고온으로 유지되고 이에 따라 해당시간에 함수율 변화폭이 크게 나타나는 것으로 판단된다.

최근 런던협약 96의정서 발효에 따라 하수 슬러지의 해양투기가 금지되고 환경 정책 강화와 향후 에너지 자원 부족을 대비하기 위해 녹색 성장이 강조되면서 슬러지를 재이용화 및 자원화 시키려는 처리 기술방법들이 개발되고 있다. 하수슬러지 처리 공정의 중점은 발생량의 감량화와 개량화를 통해 탈수 효율을 높이기 위함이며 대표적인 전처리 방법으로 물리적인 방법과 화학적인 방법으로 약품 처리하는 것이 일반화되어 있다. 본 논문에서는 폴리머 응집제를 사용하여 총 4종류의 생, 잉여, 소화, 혼합슬러지에 대해서 적합한 유기 및 무기 응집제를 주입한 후 최적의 응집 조건을 선정하여 최종적으로 슬러지 탈수성의 효율을 비교 및 평가하도록 하였다. 혼합슬러지는 생슬러지와 잉여슬러지를 같은 부피 비율로 혼합하여 제조하였다. 최적의 응집 조건을 선정하기에 앞서 기본적으로 Jar Test 실험을 시행하였으며 200rpm에서 1 ~ 3분 완속 교반, 50rpm에서 5분 급속 교반 조건을 제시하였고, 유기 폴리머와 무기 폴리머 응집제의 단일 및 이액 주입 방식에 따라 응집 반응의 특성을 비교하였다. 실험결과는 슬러지 탈수성 및 최적 응집 조건 선정의 지표로서 응집을 형성시키고 방치 후, 고액 분리를 통해서 상등수의 탁도, pH, ORP, SS, 흡광도 (330nm), floc size와 TTF 실험을 하여 탈수성을 측정하였다. 따라서 응집제 주입 방법에 있어서 유기 응집제의 단일 방식 주입과 무기 응집제를 첨가하여 floc의 응결도를 높이는 이액 주입 방식으로부터 탈수성 효율에 미치는 결과를 본 논문에 나타내었다.

T-N and T-P in the filtrate from Sludge Treatment Process (STP) was returned to water treatment processing, because T-N and T-P are returned, it makes overload in Advanced Treatment Process. Removal efficiency of T-N and T-P are compared both at using polymer as simple method and at using PFS and polymer as complex method when coagulants was injected in Thickener. In simple method, removal efficiency of T-N and T-P were 95.68% and 99.29% for each. In complex method, removal efficiency of T-N and T-P were 98.07% and 99.90% for each. From the result, removal efficiency of complex method was highly better than simple method. According to increasing of removal efficiency, returned T-N and T-P loading to water treatment process was decreased (Reduced amount of T-N is 0.2309 kg/hr and TP is 0.0145 kg/hr). Also, the amount of a polymer used has been decreased to 80% by using PFS.

We examined whether several reeds, which are found around Ulsan area, could be used for downflow reed-bed to remove pollutants of sewage. Three kinds of reed, such as Phagmites australis, Typha orientalls, and Phalaris aundinacea L., were collected from their habitats near the Taehwa River in Ulsan City. In the minimized model system of downflow reed-bed, P. australis appeared to reduce BOD more than others did but slightly increase total amount of nitrogen(N). When P. australis were placed in the sterilized water, total nitrogen was found to be significantly increased dependent on the number of experimental plant in the sterilized state, but it was rather decreased in the non-sterilized state. With these results, microorganisms attached to P.australis roots can be thought to work for removal of pollutants. Therefore, these microorganisms and their habitat, P. australis reed bed, together can be used for sewage treatment. It was suggested that oxygen is produced by photosynthesis reaction of P. austrails. The increased oxygen may help microorganisms in their habitats to work on the removal of pollutants