• 한국환경과학회지
• /
• 제24권7호
• /
• pp.917-925
• /
• 2015

Styela clava tunic is generated in large amounts as a waste from S. clava processing plants and leads to environmental problems. It destroys the beach scenery and causes a bad smell and pollution by trashing on the seashore. Therefore, purpose of this study was to investigate antioxidant and antihypertensive activities of different solvent extracts from S. clava tunic for recycling of fishery waste. Antioxidant and antihypertensive activities of all extracts were concentration-dependent. Of extracts, hot water extract showed the highest DPPH radical scavenging activity with the lowest effective concentration ($EC_{50}$) value (0.733 mg/ml). Chloroform extract exhibited the highest metal chelation activity with the lowest $EC_{50}$ value (2.696 mg/ml). Autoclaved water extract showed the highest NO radical scavenging activity with the lowest $EC_{50}$ value (0.491 mg/ml) and n-hexane extract showed the highest reducing power ($A_{700}=1.897$ at 100 mg/ml). And n-butanol extract showed the highest SOD-like activity with the lowest $EC_{50}$ value (19.116 mg/ml) and ACE inhibition activity with the lowest inhibitory concentration($IC_{50}$) value (0.149 mg/ml). These results indicate that extracts obtained from S. clava tunic may potential candidate to reduce diseases caused by various oxidative stresses and hypertension.

• 융합정보논문지
• /
• 제10권5호
• /
• pp.117-125
• /
• 2020

본 연구에서는 정화조 폐기와 주방용오물분쇄기 사용으로 수세분뇨와 음식물찌꺼기가 공공하수관로에 직접 투입되는 「새로운 공공서비스사업」(이하 사업)시행과정에서 발생하는 비용과 편익을 식별, 제시한다. 본 연구는 기존 문헌과 공학적인 관점에서 사업시행 과정에서 처리분구(소구역)별 소요비용과 사업 완료 이후 편익을 객관적인 통계자료로서 식별, 제시하는 방식으로 수행한다. 비용과 편익을 식별한 결과, 비용항목들은 하수관로 시설(배수설비, 정화조 폐쇄·관로배치 변경 등), 수질보전(우수 토실·토구, 하수저류시설 등), 공공하수처리시설(침사지와 최초침전지, 고도처리시설 등) 등에서, 편익항목에는 악취제거로 인한 건강개선, 슬러지 처리효율 제고로 에너지 생산성 증가, 음식물쓰레기 처리비용과 정화조 처리 및 유지관리비용 절감, 기존 분뇨처리시설투자 축소 등이 식별되었다. 이상의 비용과 편익항목들은 향후 사업 시행 여부를 결정하는 경제성 분석의 기초 자료로 활용될 것이다.

• 한국세라믹학회지
• /
• 제53권1호
• /
• pp.1-6
• /
• 2016

In this year, Koreans have a shortage in agricultural and drinking water due to severe algal blooms generated in major lakes. Waste oyster shells were obtained from temporary storage near the workplace at which oysters were separated from their shells. Heating ($1000^{\circ}C$ for 1 h in air) was employed to convert raw oyster shell powders into calcium oxide powders that reacted efficiently with phosphorus and nitrogen to remove algal blooms from eutrophicated wastewater. As the dispersed amount of heated oyster shell powders was increased, water clarity and visual light penetration were improved. Coagulation, precipitation and carbonation process of the heated oyster shell powders in a water purifier facilitated removal of eutrophication nutrient such as phosphorus and nitrogen, which is both beneficial and economically viable. $CO_2$ implantation by carbonation treatment not only produced thermodynamically stable CaO in oyster shells to derive precipitated calcium carbonate (PCC) but also accelerated algal removal by activation of coagulation and precipitation process. The use of oyster shell powders led to a mean reduction of 97% in total phosphate (T-P), a mean reduction of 91% in total nitrogen (T-N) and a maximum reduction of 51% in chemical oxygen demand (COD), compared with the total pollutant load of raw algal solution. Remarkable water quality improvement of algal removal by heated oyster shell powders and PCC carbonation treatment will allow utilization as water resources to agricultural or industrial use.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
• /
• pp.153-153
• /
• 2010

The world is moving towards a post-carbon society and needs clean and renewable energy for sustainable development. There are many methodological approaches which are helping this shift based on analyzed data about energy resources and which focus on limited types of energy including liquid fossil, solid fossil, gaseous fossil, and biomass (e.g. IPCC Guidelines, ISO 14064-1, WRI Protocol, etc.). We should also consider environmental impact (e.g. greenhouse gas emissions, water use, etc.) and the economic cost of the renewable energy to make a better decision. Recently, researchers have addressed the environmental impact of new technologies which include photovoltaics, wind turbines, hydroelectric power, and biofuel. In this work, we analyze the environmental impact with a carbon emission factor to present a correlation between $CO_2$ emission and the cost of energy resources standardized by the energy output. In addition, we reviewed Life Cycle Assessment (LCA) as another methodology. Researchers who are studying energy systems have ignored the impacts of entire energy systems, e.g. the extraction and processing of fossil fuels. In power sector, the assessment should include extraction, processing, and transportation of fuels, building of power plants, production of electricity, and waste disposal. Therefore LCA could be more suitable tool for energy cost and environmental impact estimation.

• Nuclear Engineering and Technology
• /
• 제43권4호
• /
• pp.335-342
• /
• 2011

As part of the Department of Energy's Fuel Cycle Research and Development Program an electrochemical technology employing molten salts is being developed for recycle of metallic fast reactor fuel and treatment of light water reactor oxide fuel to produce a feed for fast reactors. This technology has been deployed for treatment of used fuel from the Experimental Breeder Reactor II (EBR-II) in the Fuel Conditioning Facility, located at the Materials and Fuel Complex of Idaho National Laboratory. This process is based on dry (non-aqueous) technologies that have been developed and demonstrated since the 1960s. These technologies offer potential advantages compared to traditional aqueous separations including: compactness, resistance to radiation effects, criticality control benefits, compatibility with advanced fuel types, and ability to produce low purity products. This paper will summarize the status of electrochemical development and demonstration activities with used nuclear fuel, including preparation of associated high-level waste forms.

• Journal of the Korean Wood Science and Technology
• /
• 제51권6호
• /
• pp.481-492
• /
• 2023

The ecofriendly lifestyle has attracted considerable support for sustainable development. Natural dyes, as sustainable products, have become a research focus and development area for many scientists. Ecofriendly processing also supports circular sustainable development. This study effectively obtained tannins as a natural dye from merbau (Intsia bijuga) sawdust using water as an ecofriendly solvent. Merbau sawdust is an underutilized industrial waste. Temperature and solid-solvent ratio variations were performed to extract tannins from merbau sawdust. Temperature and solid-solvent ratio positively affected solution yield and tannin concentration. The optimal condition was identified using response surface methodology and experimental observations. A yield of 0.2217 g tannins/g merbau was obtained under the conditions of 333.15 K and 0.125 solid-solvent ratio. Extraction was controlled by convective mass transfer at the interface of solid particles.

• Journal of Biosystems Engineering
• /
• 제20권3호
• /
• pp.250-261
• /
• 1995

This study has been performed to develop an agricultural waste incinerator to combust the rice hull originated from RPC with the typical disposal treatment capacity of 30kg/h and to test performance of the developed incinerator. Experimental results are summarized as following. 1. The optimum feed rate of rice hull of the incinerator is 30kg/h with air ratio of 1.5. 2. The contents of $SO_2$ in flue gas is maximum 18ppm(when rice hull feed rate was 20kg/h and air ratio of 1.5), minimum 7ppm(when rice hull feed rate was 30kg/h and air ratio of 1.5) and average 11ppm. So there is no environmental pollution problem for the incinerating treatment of rice hull of the RPC. 3. The temperature of water of heat exchanger are $53^{circ} C$ and $62^{circ} C$ with water flow rate $3{ell}/min$ and $1.5{ell}/min$ at the optimum combustion condition, respectively. 4. According to theoretical energy calculation, the energy from rice hull combustion may be amounted as much as 80%~190% of energy supplied by kerosene required by RPC.

• 한국지구물리탐사학회:학술대회논문집
• /
• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
• /
• pp.335-339
• /
• 2003

The estimation of seawater intrusion into deep aquifers has been becoming an important subject in terms of site characterization for geological disposal of radioactive waste. Conventional direct-current resistivity methods have been used for ground water explorations and recently have been applied to environmental problems. However, electromagnetic methods are more practical and useful for such a deep investigation. We consider audio-frequency magnetotelluric (AMT) and surface-to-borehole electromagnetic (EM) tomography methods as promising tools for the investigation of deep aquifer. These methods were tested in the Hasunuma area, Chiba Prefecture, Japan. Although the study area is in an urban area, high-quality AMT data were acquired, which was mainly accomplished by night-time data recording and remote-reference data processing. One-dimensional inversion results of the AMT data revealed two extremely conductive zones, which is consistent with the electrical conductivity profile of pore water in core samples. It can be interpreted as the seawater intrusions into both zones. However, the chemical analysis of the groundwater sampled in the deep zone suggests that this groundwater must be fossil seawater that had been confined during sedimentation processes. In addition, the permeability coefficient of the deep layer is very low. Thus the deep conductive zone corresponds to the fossil seawater regarded as being difficult to flow.

• 에너지공학
• /
• 제25권2호
• /
• pp.65-78
• /
• 2016

광촉매 연구의 초기는 태양에너지의 전환 및 저장에 관련된 분야들로부터 개발되어 왔다. 최근에는 광 또는 광촉매의 존재 하에서 자외선을 조사하여 물의 정제 및 폐수처리와 각종 유기화합물의 분해연구가 활발하게 진행되고 있다. 또한 산화물질-카본나노튜브, 그래핀 나노복합체 등이 광촉매물질로서 연구되고 있다. 이와 같은 복합체는 열적, 화학적으로 안정하기 때문에 플렉서블 소자를 포함한 광분해 태양전지 및 나노전자 소자를 구성하는 재료로서 적당하다.

• 한국건설순환자원학회논문집
• /
• 제5권4호
• /
• pp.122-128
• /
• 2010

정수 슬러지는 해양투기가 금지됨에 따라 매립되거나, 성토재, 복토재 등과 부가가치가 거의 없는 용도로 활용되고 있다. 정수슬러지는 하수슬러지와는 달리 유기물의 함유량이 높지 않은 무기성 슬러지이며, 적절히 가공할 경우 유용한 자원으로 사용할 수 있음에도 불구하고 적절히 활용되지 못하고 있다. 본 연구팀은 정수슬러지를 인산으로 수열반응하여 인공제올라이트를 합성하였다. 합성된 제올라이트는 다공성으로 탈취능이 매우 우수한 분말이지만, 건축자재로 사용하기 위해서는 일정한 형상으로 고화할 필요성이 있다. 본 연구에서는 합성한 인공제올라이트의 특성과 이를 다양한 고화제로 고화하여 그 특성을 분석한 것이다. 실험결과 소석회가 가장 적절한 고화특성을 보이고 있었으며, 최적 사용조건은 전체 분말 중량의 30-60%인 것으로 나타났다. 고화체의 탈취 성능은 원료인 인공제올라이트에는 못미치지만 매우 우수한 것으로 나타나 건축물용 탈취 재료로서의 사용가능성을 확인할 수 있었다.