1936년 7월 4일 경상남도 하동군 화개면을 진앙지로 하는 규모 5의 지진이 발생하였다. 이 지진으로 인하여 쌍계사 경내 건물과 문화재가 손상을 입었으며 금당 앞에 위치한 오층석탑의 탑두(종형석)가 추락하였다. 쌍계사 지진의 세기를 정량적으로 평가하기 위하여 철저한 고층을 거쳐서 실물크기의 석탑 모델을 제작하였다. 제작된 석탑모델을 진동대에 탑재하여 낮은 진폭에서 석탑모델의 동특성을 확인하는 예비시험과 지진파의 지진가속도를 증가시켜 가면서 석탑모델의 거동 특성을 규명하는 본 시험을 실시하였다. 석탑모델의 제작과정과 시험 절차에 관하여 상세히 기술하였고 진동대 시험 결과를 제시하고 그 결과에 관하여 논하였다.

This study investigated microbial communities and their diversity in a full-scale mesophilic anaerobic digester treating sewage sludge. Influent sewage sludge and anaerobic digester samples collected from a wastewater treatment plant in Busan were analyzed using high-throughput sequencing. It was found that the microbial community structure and diversity in the anaerobic digester could be affected by inoculation effect with influent sewage sludge. Nevertheless, distinct microbial communities were identified as the dominant microbial communities in the anaerobic digester. Twelve genera were identified as abundant bacterial communities, which included several groups of syntrophic bacteria communities, such as Candidatus Cloacimonas, Cloacimonadaceae W5, Smithella, which are (potential) syntrophic-propionate-oxidizing bacteria and Mesotoga and Thermovigra, which are (potential) syntrophic-acetate-oxidizing bacteria. Lentimicrobium, the most abundant genus in the anaerobic digester, may contribute to the decomposition of carbohydrates and the production of volatile fatty acids during the anaerobic digestion of sewage sludge. Of the methanogens identified, Methanollinea, Candidatus Methanofastidiosum, Methanospirillum, and Methanoculleus were the dominant hydrogenotrophic methanogens, and Methanosaeta was the dominant aceticlastic methanogens. The findings may be used as a reference for developing microbial indicators to evaluate the process stability and process efficiency of the anaerobic digestion of sewage sludge.

This research presents effectiveness of fiber-reinforced polymer column jacketing system for a non-ductile reinforced concrete building frame constructed before the 1970s. To investigate the retrofit effects, a series of full-scale dynamic tests for the retrofitted test frame was conducted, and the dynamic responses were compared to those of the non-retrofitted test frame. The effectiveness of the retrofit system was investigated in terms of response reductions, damage mechanisms and drift concentration factors.

In this research, the target process was a modified type of a conventional aeration tank with four different influent feeding points and alternated aeration to obtain nitrogen removal. For more accurate switching of influent feeding, the process was operated under a designed control strategy based on monitoring of NH4-N and NOX-N concentrations in the tank. However, the strategy did have some limitations. For example, it was not sensitive to detecting the end of each reaction when losing the balance between nitrification and denitrification of each opposite part of biological tank. To overcome the limitations of the existing control strategy, a diagnosis-based control strategy was suggested in this research using the diagnosis results classified as normal (N), ammonia accumulation (AA) and nitrate accumulation (NA). Using the pre-designed rules for control actions, the aeration and volume of the aerated part of the reactor could be increased or decreased at a fixed mode time. In simulations of the suggested diagnosis-based control strategy, the NH4-N and NOX-N removal rates in the reactor were maintained at higher levels than those of the existing control strategy.

In the case of railway bridges passing through the urban area, bridge type with excellent noise reduction performance is required. The bridges under development are steel composite through bridges, which is a composite structure of upper flanges with concrete, and the section bridges themselves, which surround the train, have the feature of acting as a sound barrier. In this paper, the performance test of air conduction noise is performed by the 20m full scale model test of new type steel composite through bridge.

There is a rising interest of depletion of deposited fossil fuel and environmental pollution, inducing extensive studies to find new alternative sustainable energy sources to replace current petroleum based energy usage. As one of solutions, anaerobic digestion (AD) treating organic wastes has been considered one of the most promising processes owing to its sustainability, low production of sludge, unnecessariness of aeration, and biogas generation. Swine wastewater is characterized by high strength of organic matter contents, so it is regarded as a potential feedstock to produce methane through AD process. To investigate the functional relationship between the microbial communities and anaerobic process performance, regular seasonal sampling was done at four full scale anaerobic digesters treating swine wastewater in South Korea for two years. As results of process and microbial community analyses, chemical oxygen demand (COD) removal efficiency was monitored to proportional to those of carbohydrates, proteins and lipids. Methanogenic and bacterial populations were also positively related to the removal efficiencies of carbohydrates and lipids. However, proteins removal efficiency was independent of microbial population. It means that microbial communities in full scale anaerobic digesters are most likely to be mainly associated with carbohydrates and/or lipids metabolisms, indicating that proteins may be putative recalcitrant contents in wastewater. The microbial population tends to be more affected by places rather than seasons; however, with respect to seasons, the highest species abundances were observed mainly at winter. This implied that rising temperature in the anaerobic digesters in summer would be not suitable for the growth of mesophilic microorganisms, known to be predominant in anaerobic process. Actually, this speculation is supported by the fact that the highest removal efficiency of COD was measured at winter samples. The marked information in this study must provide a real insight into the effective field operation of anaerobic digestion.

Biological nitrogen removal is generally accomplished by aerobic nitrification coupled with anoxic denitrification. Many commercial wastewater treatment plants (WWTPs) use external carbon source, such as methanol, to support heterotrophic denitrification process. Using organic wastes as an alternative to commercial carbon sources could thus be beneficial by saving the expense as well as reducing the environmental footprint. Here we report a full-scale (treating 2300 m3 wastewater/d) WWTP that previously utilized a butanediol-based organic waste as the sole external carbon source, which diversified the carbon sources by using a second organic waste generated from food waste recycling. Process parameters were extensively monitored for seven months at all biological unit processes, the aerobic and anoxic tanks, as well as the recirculation flow. Bacterial community structures were analyzed at anoxic tank using next-generation sequencing. The WWTP showed a stable nitrogen-removing performance over the seven months period. The estimated COD/N utilization ratio for food waste-recycling wastewater (FRW) was near 30. The bacterial populations significantly shifted during the operation. Lactobacillaceae and Prevotellaceae were the major bacterial families in the FRW, whereas the denitrification tank was populated by many families including Saprospiraceae, Nannocystaceae, Chitinophagaceae, Eubacteriaceae, and Rhodocyclaceae. Detailed discussion of the results will be presented at the conference.

Anaerobic digestion is one of the most economical ways to treat organic wastes; the production of excessive sludge is limited; aeration is not required; operation cost is low; valuable energy resource (methane) is produced. However, propionate, an intermediate substance during the process, is known to inhibit biochemical process at high concentration; but it is difficult to be degraded biologically as its oxidation is thermodynamically unfavorable (△G>0). However, there are several microorganisms which could oxidize propionate fully by their syntrophic association. Therefore, in this research, the propionate enrichment culture was produced in large amount (~1L), and the main players which are responsible for utilizing propionate are identified. Furthermore, the kinetic parameter was obtained from this research. Seed came from two different full-scale anaerobic digesters which is located in Joongrang (JR) and Sincheon (SC). 16s rRNA gnee based metagenomics results indicated that Smithella propionica and Methanobacterium beijingense were the most dominant species in all seeds. The fact that bacterial family Syntrophomonadaceae and archaeal genus Methanosaeta were also found significantly in all seeds means that there might be symbiotic relationship among propionate oxidizing bacteria, butyrate oxidizing bacteria, hydrogenotrophic methanogens and acetotrophic methanogens in complete oxidation of propionate. Based on the first order kinetic which indicated propionate degrading rate, k (1/day) on JR and SC was represented 0.0243 and 0.0223, respectively. Also, based on Modified-Gompertz model, umax on JR and SC was represented as 0.024 and 0.016, respectively.

The static aerodynamic forces are composed of six components. Three components of them such as drag force, lift force and pitching moment are the biggest influence on the structure. These aerodynamic forces are generally evaluated from wind tunnel test or CFD. In this study, drag and lift force coefficients are estimated using relation of actual and analytical displacements. The actual displacements are measured by monitoring system when the bridges were under the typhoon. The analytical displacements due to uniform load are calculated by FEM. Also, the adequacy of estimation method was conformed by comparing the result of this study with that from the wind tunnel test of the similar bridge section.

본 논문에서는 실물 콘크리트 거더 교량의 가속도 응답 신호를 이용하여 구조물의 상태변화를 경보한 후 그 위치 변화를 검색하는 2단계 구조건전성 모니터링 체계를 제시하였다. 먼저, 2경간 연속 콘크리트 거더 교량인 미호천교를 대상교량으로 선정하였으며, 볼링공을 이용한 강제진동 실험으로부터 동특성을 추출하였다. 다음으로, 미호천교의 2단계 구조건전성 모니터링 체계 구축을 위한 손상 발생 경보 및 손상 위치 검색 기법들을 선정하였다. 손상 경보 기법으로는 시간영역 특징을 이용하는 자기회귀모델과 주파수응답함수의 상관계수, 주파수응답비보증지수를 선정하였다. 손상 위치 검색 기법으로는 모드변형에너지기반 손상지수법을 선정하였다. 마지막으로, 덤프트럭을 이용한 정적 재하 실험을 통해 2단계 손상 모니터링 체계의 적합성을 검증하였다.

The purpose of this research was evaluated economical effect to apply alternative external carbon source. Conventional activated sludge process in municipal wastewater treatment plant was adapted and introduced to Biological nutrient removal processes to meet the newly enforced effluent quality standard for nutrient removal in Korea. Low COD/NH4+-N ratio and higher nutrient concentration of influent characteristics force to inject external carbon source for denitrifying recycled nitrate. In the most case, methanol was used as external carbon source. But Methanol is expensive and very dangerous in handling. So we could find cheaper and safer external carbon source substituted methanol in last study. This alternative external carbon source is named RCS(recoverd carbon source) and a by-product of fine chemical product at chemical plant. When RCS was applied real municipal wastewater treatment plant, average 55~65% of T-N removal efficiency, 8.8mg/l of effluent T-N concentration, 11.3mg/l of effleunt COD concentration were obtained without effluent COD increase as against used methanol. To apply RCS in municipal wastewater treatment plant obtain approximately 74.5% expenditure cost reduction in comparison with methanol dosage cost.