본 연구는 폐타이어 고무분말 개질 아스팔트(crumb rubber modified asphalt, CRMA) 공정조건에서 반응온도, 혼합반응시간 및 유연성 개질제의 영향을 조사하였다. 저온에서 아스팔트바인더와 개질 아스팔트의 온도 민감성과 접착특성은 침입도와 인장접착강도를 통하여 측정하였다. 유연제와 공정온도가 인장접착강도와 강인화 에너지의 중요한 요소임을 확인하였다. 더 높은 혼합온도와 연성 개질제에서 CRMA의 인장접착물성이 향상되는 것은 아스팔트바인더와 개질 아스팔트의 연성구조에 기인한다. CRMA의 물리적 특성의 개선은 CR과 아스팔트바인더간의 상용성에 있다. 유연제가 CR과 아스팔트바인더 안에 침투되어, 유연제에 의해 개질된 CRMA는 CRMA보다 접착특성이 증가하였음을 확인하였다.

The covered stream of cities are considered an odor source. Also, the public do not want a wastewater treatment plant(WWTP) near their properties due to the emission of odor emanating from such sources, although they play an important role in urban development. The purpose of this study is to analyze the pattern distribution of the odorous compounds from the Nambu WWTP and Youngho stream in Busan. odor sampled four times were analyzed by instrumental analysis method and indirect olfactory method. The kinds of offensive odorous compounds examined are acetaldehyde, propion aldehyde, hydrogen sulfide, methyl mercaptan, dimethyl sulfide and ammonia. Also, Concentration of air pollutants has been calculated by ISCST3 models. At the result of this study, The Nambu WWTP releases sulfur compounds. And the major odorous were hydrogen sulfide (1,475 ppb) and acetaldehyde (95 ppb) at Youngho stream. The stink which residents feel will point out the Nambu WWTP mainly if the odor is removed with the improvement of a Youngho stream. Accordingly, we should pay more attention to appropriate components to processes in odor reducing plan at Nambu WWTP.

This study was performed to investigate the possible uses of waste sludge for the removal of heavy metal ions. The adsorption experiments were conducted with wastes such as sewage treatment sludge, water treatment sludge and oyster shell to evaluate their sorption characteristics. Heavy metals selected were cadmium, copper and lead. In the sorption experiments on the sewage treatment sludge, water treatment sludge, oyster shell and soil, sorption occurred in the beginning and it reached equilibrium after 40 minutes on the oyster shell and 4 hour on the sewage treatment sludge and water treatment sludge. Results of Freundlich isotherms indicated that sewage treatment sludge could be properly used as an adsorbent for heavy metals and sorption strength of heavy metals was in the order of Pb > Cu > Cd. In the influence of pH on the adsorbents, sorption rate was more than 80% in pH 4 and most of heavy metals were adsorbed in pH 9. Adsorption rate of Cd decreased with decreasing pH and then adsorption rate of Cu was lower in soil.

The objectives of this study were to investigate the desulfurization kinetics of paper sludge and limestone in a fluidized bed reactor according to bed temperature and air velocity. The experimental results were presented as follows ; First, the bed temperature had a great influence on the desulfurization efficiency of limestone and paper sludge. In paper sludge, the optimum condition in desulfurization temperature was at 800℃ and in limestone, that was at 850℃ or 900℃. Second, as air velocity increased, the desulfurization efficiency(or the absorbed amount of sulfur dioxide) by limestone and paper sludge decreased. And the absorbed amount of sulfur dioxide by paper sludge was larger than that of by limestone. Third, as the velocity increased and the optimum desulfurization temperature became, ks and the removal efficiency increased. So, ks, kd highly depended on the air velocity and bed temperature.

Selective catalytic reduction and selective non-catalytic reduction processes are mainly used to treat nitrogen oxidants generated from fossil-fuel combustion. Especially, the selective non-catalytic reduction process can be operated more economical and designed more simply than the selective catalytic reduction. For this reason, many researchers carried out to increase the removal efficiency of nitrogen oxidants in the condition of low oxygen concentration by using the selective non-catalytic reduction process. However, this study was flue gas contained high oxygen concentration of 20(v/v%) with ammonia as a reducing agent. Moreover, it carried out experiment with many factors that are reaction temperature, retention time, initial NO concentration, NSR(normalized stoichiometric ratio). It was determined optimal operating conditions to improve NO removal efficiency with SNCR process. The De-NOx efficiency was increasesd with NSR, initial NO concentration and retention time increasement. This study has NO removal efficiency over 80% in the high oxygen concentration as well as low oxygen concentration. The injection of reducing agent may be considered for SNCR process and facility operation in 850℃ of optimal condition.

One of the Musty and earthy smell compounds in raw water is generally attributed to 2-methylisoborneol (2-MIB). It is well known that activated carbon and oxidants such as O3, ClO2 are effective ways to control 2-MIB. In isotherm equilibrium experiments, 2-MIB in distilled water was much more adsorbed to the activated carbon(A/C) than raw water containing dissolved organic carbon (DOC). The Freundlich constants(k) of distilled water and raw water were 3.36 and 0.049, and 1/n values were 0.80 and 0.42, respectively. The 2-MIB residual rate were Y = e-0.55x～ e-0.54x with Ozone(O3) dose by 5 minutes contact time at the 241 and 353 ng/L initial concentrations. The 2-MIB residual rate were Y = e-0.32x～ e-0.35x with Chlorine dioxide(ClO2) dose by 15 minutes contact time at the 89 and 249 ng/L initial concentrations. 2-MIB was decreased from 1911 ng/L to 569ng/L by post-ozonation(70%removal efficiency) and removal efficiencies of 2-MIB by the following 4 kinds Granular Activated Carbon(GAC) process such as coal base, coconut base, wood base and zeolite+carbon base were 95.8, 89.5, 88.4, and 93.7% respectively.

농촌 소하천의 수리학적 및 수질특성을 반영한 모형을 개발하였다. 모형구조 설계시 제어체적 기법을 활용하여 하천 형상, 수질 및 유량의 변화가 심한 농촌 유역의 소하천에 대한 수질의 모의하였다. 개발한 모형에 난수발생기법을 도입하여 최적 반응계수와 모형구조를 추정하였다. 또한 모형 보정기준의 일반화를 위해 동의지표와 효율계수를 도입하여 매개변수추정의 신뢰성 향상을 도모했다. 모형의 적용성을 검증하기 위해 경남 김해시 한림면 용덕천에서 수질을 채취하여 분석

Sorbents of calcined limestone and oyster particles having a diameter of about 0.63㎜ were exposed to simulated fuel gases containing 5000ppm H2S for temperatures ranging from 600 to 800℃ in a TGA (Thermalgravimetric analyzer). The reaction between CaO and H2S proceeds via an unreacted shrinking core mechanism. The sulfidation rate is likely to be controlled primarily by countercurrent diffusion through the product layer of calcium sulfde(CaS) formed. The kinetics of the sorption of H2S by CaO is sensitive to the reaction temperature and particle size, and the reaction rate of oyster was faster than the calcined limestone.

The objectives of this study were to investigate the characteristics of desulfurization under different experimental conditions and the effects of desulfurization in a fluidized bed combuster installed with the screen. The experimental results were as follows ; First, as the height of fluidized bed combustor becomes higher, the concentrations of SO_2 mainly increased and sulfur retion of paper sludge was higher than that of natural limestone. Second, the desulfurization by natural limestone occurred at in-bed and the desulfurization by paper sludge occurred in the whole of fluidized bed combuster. In additiion, we identified calcium sulfate by the analysis of SEM and XRD. Third, screen at splash region increased sulfur retention 2∼5%, air velocity and anthracite fraction had a little effect on the sulfur retention.

It has been studied that combustion and the production of air pollution of anthracite - bituminous coal blend in a fluidized bed coal combustor. The objects of this study were to investigate mixing characteristics of the particles as well as the combustibility of the low grade domestic anthracite coal and imported high calorific bituminous coal in the fluidized bed coal combustor. They were used as coal samples ; the domestic low grade anthracite coal with heating value of 2,010㎉/㎏ and the imported high grade bituminous coal with heating value of 6,520㎉/㎏. Also, the effects of air flow rate and anthracite fraction on the reaching time of steady state condition have been studied. The experimental results are presented as follows. The time of reaching to steady state was affected by the temperature variation. The steady state time was about 120 minute at 300scfh which was the fastest. It has been found that O_2 and CO_2 concentration were reached steady state at about 100 minute. It has been found that O_2 concentration decreased and CO_2 concentration increased as the height of fluidized bed increased. It was found that splash zone was mainly located from 25㎝ to 35㎝ above distributor. Also, as anthracite fraction increased, the mass of elutriation particles increased, and CO_2 concentration decreased. As air flow rate increased, O_2 concentration decreased and CO_2 concentration increased. Regardless of anthracite fraction and flow rate, the uncombustible weight percentage according to average diameter of elutriation particles were approximately high in the case of fine particles. As anthracite fraction and air flow rate increased, elutriation ratio increased. As anthracite fraction was increased, exit combustible content over feeding combustible content was increased. Regardless of anthracite fraction, size distribution of bed material from discharge was almost constant. Over bed temperature 850℃ and excess air 20%, the difference of combution efficiencies were little. It is estimate that the combustion condition in anthracite-bituminous coal blend combustion is suitable at the velocity 0.3m/s, bed temperature 850℃, the excess air 20%.

The purpose of this study was to examine the questioning styles in middle school environmentology textbook in terms of frequency, type, and placement of questions. It was also to analyse and to compare the kinds of scientific inquiry processes elicited by the questions in the topics of textbooks. The instrument was the Textbook Questing Strategies Assessment Instrument (TQSAI) developed the Cooperative Teacher Preparation Project, University of California. The average number of questions per topic was only 1.09 and the ratio of questions to sentences was 2.5%. Most of questions were in explanatory place(75%). Nearly 90% of experienced questions types were reasoning or application. The frequencies of non-experiential question were higher than those of experiential question. In action, there were much kinds of question-styles.