• 한국물환경학회지
• /
• 제34권2호
• /
• pp.149-156
• /
• 2018

Oxidation of Ciprofloxacin, Trimethoprim, and Enrofloxacin by ozone was experimentally investigated to observe the effects of background water quality (such as ultrapure water, humic acid, and biologically treated wastewater) and water temperature on the removal rate of these antibiotics, and, thereby, to be able to provide design information when the ozone treatment process is adopted. Initial concentrations of the antibiotics spiked to $10{\mu}g/L$, and the ozone dose was 1, 2, 3, 5, and 8 mg/L. While the removal rate of Ciprofloxacin under ultrapure water background by ozone oxidation was over 99%, the removal rate under humic acid and biologically treated wastewater background was markedly lower, in the range of 49.3% ~ 99% and 19.8 % ~ 99 %, respectively. When water temperature is decreased from $20^{\circ}C$ to $4^{\circ}C$, the removal rate is reduced from the range of 19.8% ~ 99 % to the range of 7.5 % ~ 99 % under a biologically treated wastewater background. The effects of background and temperature on the removal rate of Trimethoprim and Enrofloxacin were similar to that of Ciprofloxacin, but the degree was different. Therefore, it is concluded that the background of water to be treated, as well as water temperature, should be taken into consideration when the design factor, such as ozone dose, is determined, so that the treatment objective of the ozone treatment process can be most effectively met.

• 상하수도학회지
• /
• 제31권4호
• /
• pp.347-356
• /
• 2017

Oxidation of erythromycin, sulfamethazine and sulfathiazole by ozone was experimentally investigated to see the effects of background water quality such as ultrapure water, humic acid and biologically treated wastewater and water temperature on the removal rate, consequently to provide design information when the ozone treatment process is adopted. Initial concentration of the antibiotics was spiked to $10{\mu}g/l$ and ozone dose was 1, 2, 3, 5, 8 mg/l. While the removal rate of erythromycin under ultrapure water background by ozone oxidation was over 99%, that under humic acid and biologically treated wastewater background was markedly reduced to the range of 59.8%~99% and 17.0%~99%, respectively. When water temperature is decreased from $20^{\circ}C$ to $4^{\circ}C$, the removal rate is reduced from the range of 17.0%~99% to the range of 9.4%~97.4% under biologically treated wastewater background. The effects of background and temperature on the removal rate of sulfamethazine and sulfathiazole were similar to erythromycin, but the degree was different. Therefore, it is concluded that the background of water to be treated as well as water temperature should be taken into consideration when the design factor such as ozone dose is determined to meet the treatment objective in the ozone treatment process.

• Journal of Astronomy and Space Sciences
• /
• 제14권2호
• /
• pp.297-311
• /
• 1997

산소 기체($O_2$)를 전기 방전에 의해 완전히 오존($O_3$)으로 만든 후 $30~150^{\circ}C$범위의 온도에서 열분해 시켰다. 열분해 결과 얻어진 산소 기체를 동위원소 질량분석기로 분석하여 동위원소 분할효과를 측정하였다. 낮은 온도에서는 생성된 산소 기체가 오존에 의해 더 가벼우면서 질량에 의존하는 일반적인 동위원소 분할효과를 보이다가, $110^{\circ}C$ 이상의 실험에서는 산소 기체가 더 무거워지면서 $^{17}O$와 $^{18}O$가 $^{16}O$에 비해 같은 양 만큼씩 많아지는 질량과 무관한 분할효과를 나타냈다. 같은 재질(파이렉스)의 반응 관을 이용한 연구들과 그 범위와 경향이 거의 일치하였다. 실험 결과를 이용하여 산소 생성 비율이 일정한 값이 되는 순간의 동위원소 분할 인자들에 대한 값을 최소자승 법을 이용하여 구하였다. 관측된 현상들은 오존의 열분해 메커니즘의 이해와 운석 및 성층권에서의 산소 동위원소의 질량에 무관한 분포에 대한 이해에 중요한 역할을 할 것이다.

• 대한환경공학회지
• /
• 제22권10호
• /
• pp.1825-1832
• /
• 2000

유류화합물(디젤)로 오염된 불포화층 토양에 대한 현장오존복원공정의 기초연구로, 토양조건에 따른 오존의 이동과 분해, 디젤과의 반응경향을 조사하였다. 건조상태에서 유기물을 제거한 모래와 glass beads 충진컬럼에서 기상 오존의 분해를 조사한 결과 일차반응으로 가정시 반응 속도상수값(k)이 각각 $9.9{\times}10^{-3}s{^{-1}}$와 $4.3{\times}10^{-4}s{^{-1}}$로 나타나 모래의 경우 철 (Fe), 망간(Mn) 성분 등의 촉매작용으로 25배 가량 반감기가 짧은 것을 확인할 수 있었다. 디젤로 오염시킨 현장 토양과 모래를 컬럼에 충진하여 동일조건하에서 오존주입시 토양입자의 크기와 유 무기물의 함량 차에 의한 오존이동상에 지체효과 및 소모량의 차이를 관찰하였고, 50mL/min의 유속에서 공기만을 주입시 DRO(diesel range organic) 기준 초기 디젤총량($800{\pm}50mg/kg$)의 30%가 제거된데 비해 오존을 6mg/min으로 16시간 주입한 결과 각각 80% 이상이 제거되었다. 오존주입시간에 따라 컬럼의 유출 입부에 잔류하는 TPH(total petroleum hydrocarbon)와 DRO 중 aliphatic계열 8개 물질들의 농도를 비교/분석한 결과, 낮은 탄소수 물질들로의 전환과정을 거쳐 유체의 흐름에 따라 컬럼 밖으로 이동됨을 확인하였고, 토양내 수분함량은 오염 토양복원에 오존을 적용시 중요한 인자임을 확인하였다.

• 상하수도학회지
• /
• 제18권5호
• /
• pp.598-607
• /
• 2004

In this study, the effects of two pre-treatment processes were observed prior to membrane filtration: pre-coagulation and pre-ozonation. To compare the effect of two above-mentioned pre-treatments, we adopted the four schemes: first one is direct membrane filtration of river surface water, second one is membrane filtration after pre-coagulation, third one is membrane filtration after pre-ozonation and fourth one is membrane filtration after pre-coagulation and pre-ozonation. There are two exceptional characteristics in applied processes. One is the usage of the MF membrane which has high ozone resisting characteristic. Therefore, ozone resides in membrane module during filtration. The other is adoption of Jet Mixed Separator (JMS) as coagulation-sedimentation process. The change in transmembrane pressure and permeate water quality were also examined. As a result, considering the filtration performance efficiency and permeate water quality, the process composed of filtration with combination of both pre-coagulation and pre-ozonation was proved most effective. The improved efficiency was due to the reduction of loading rate of fouling inducing materials to membrane module by coagulation process as well as variable reactions, such as degradation, particle destabilization and coagulation, occurred by residual ozone in membrane module. The additional effect of pre-coagulation before pre-ozonation is suppression of AOC, one of the by-products induced by ozonation. Therefore, combination of pre-coagulation and pre-ozonation is the effective process to overcome the major de-merit of ozonation i.e. by-products formation.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.1678-1683
• /
• 2003

DBD(Dielectric Barrier Discharge) plasma in air is well established for the production of large quantities of ozone and is more recently being applied to aftertreatment processes for HAPs(Hazardous Air Pollutants). Although DBD high electron density and energy, its potential use as nano and sub-micron sized particle charging are not well known. Aim of this work is to determine design and operating parameters of a two-stage ESP with DBD. DBD and ESP are used as particle charger and precipitator, respectively. We measured particle precipitation efficiency of two-stage ESP and estimated ozone decomposition of both pelletized $MnO_2$ catalyst and pelletized activated carbon. To examine the particle precipitation efficiency, nano and sub-micron sized particles were generated by a tube furnace and an atomizer. AC voltage of $7{\sim}10$ kV(rms) and 60 Hz is used as DBD plasma source. DC -8 kV is applied to the ESP for particle precipitation. The overall particle collection efficiency for the two-stage ESP with DBD is over 85 % under 0.64 m/s face velocity. Ozone decomposition efficiency with pelletized $MnO_2$ catalyst or pelletized activated carbon packed bed is over 90 % when the face velocity is under 0.4 m/s in dry air.

• 한국응용과학기술학회지
• /
• 제28권2호
• /
• pp.251-257
• /
• 2011

The processes for the preparation of ZnO powder by using EAF(electric arc furnace)dust was studied by wetting method which are divided to two steps, carried out of the elution processes by various concentrations of sulfuric acid is reacted with EAF dust as the former, and the latter were performed by a number of specified processes, which are leaching process depends on various pH, cementation, ozone and heat treatment processes etc. Experimental results showed that the appropriate pH range is pH7.5~8.0 and the resulting zinc content is range of 37~38%, the residual quantities of the heavy metals are less than 3ppm individually by cementation process except Mn, even though the Mn metal could not be removed by cementation process but was removed up to 0.2ppm by the ozone process from 70ppm initially. Finally, 80.2% of ZnO was obtained by the heat treatment at $500^{\circ}C$.

• 한국어병학회지
• /
• 제12권1호
• /
• pp.32-41
• /
• 1999

오존처리 해수중에 함유하는 잔류 옥시던트(TRO)가 양식 넙치의 생존, 혈액성상과 삼투질 농도, 산소소비 및 아가미 조직에 미치는 독성 영향을 조사하였다. TRO에 노출된 넙치의 48-hr 및 96-hr $LC_{50}$은 각각 26.4 와 22.3ppb이었고, 47ppb에서는 3시간 이내에 모두 치사하였으나 13ppb에서는 96시간 동안 폐사발생이 없었다. TRO 24~39ppb 농도범위에 노출된 넙치의 hematocrit, 헤모글로빈, 적혈구 수, 혈중 sodium과 chloride 이온 및 삼투압 농도는 TRO 농도가 높을수록 유의하게 증가하였고, 아가미 조직은 아가미 상피층이 모세혈관으로부터 박리되고, 괴사와 상피새포의 증생이 관찰되었다. 산소소비율은 TRO 농도가 높고, 노출이 계속될수록 감소하였다. 13ppb에서는 아가미 조직과 생리상태에 미치는 변화는 관찰되지 않았으나 혈당은 유의하게 증가하였다. 그러나 활성탄으로 TRO를 제거한 대조구에서는 오존의 독성 영향은 관찰되지 않았다. 잔류오존에 노출된 넙치는 삼투질 농도의 생리적 불균형 및 아가미 손상과 상피세포의 증생에 의한 산소섭취 부족이 치사를 유발하는 것으로 나타났다. 본 연구의 결과 해산어 양식장에서 오존을 사용할 경우에는 오존처리수중의 TRO는 제거하여야 하며, 비록 저농도라도 장기간 노출되면 양식어류의 생존과 생리상태에 미치는 영향은 현저할 것으로 평가되었다.

• 한국토양환경학회지
• /
• 제4권3호
• /
• pp.3-15
• /
• 1999

기존의 SVE 공정에 공기 대신 오존을 주입하여 유류물질의 지중분해를 유도하고 추출가스의 처리부담을 최소화할 수 있는 복원 신공정 개발을 위한 기초연구를 수행하였다. 이를 위하여 비휘발성 유류물질인 디젤유를 처리대상물질로 하여 토양칼럼실험을 통해 오존주입에 의한 지중분해 가능성을 검토하였다. 수분함량 8.39%의 실토양에 디젤유를 혼합하여(초기농도 1,485mg-DRO/kg-soil)칼럼에 충진시킨 후 119.0$\pm$6.1mg/L의 농도를 가지는 오존가스를 50mL/min의 유량으로 연속 주입하였을 때 14시간 반응후 칼럼 상 하부의 디젤유 제거율은 각각 87.9%, 100.0%를 나타내어 비교적 빠른 시간내에 효과적으로 처리되는 것으로 나타났다. 한편 동일한 조건에서 오존가스 대신 공기를 주입하였을 때 공기 유입 및 유출부 모두 총 14시간 동안의 접촉시간 동안 30%이내의 제거율을 나타냄에 따라 디젤오염토양에 대한 기존 SVE공정의 적용한계를 확인하였다.

• 상하수도학회지
• /
• 제22권2호
• /
• pp.227-232
• /
• 2008

The masking effect of chlorine on algae-related taste and odor(T&O) compounds has long been an important issue for water suppliers. In this study, masking experiments with chlorine were performed on two kinds of treated water and one of raw water. After adding chlorine(0 to 0.8 mg/L) to water samples, odor intensity was evaluated by a newly developed sensory method(2-out-of-5 odor test) for three days along with the measurement of residual chlorine concentration. Even though the relationship between the residual chlorine concentration and odor reported by the sensory analysts was not always coincident, it was proved that residual chlorine more than a certain concentration could completely mask both added geosmin and naturally occurring T&O compounds. For the sand-filtered water spiked with 10 ng/L of geosmin, 0.12-0.18 mg/L of residual chlorine was necessary to achieve complete masking. In the case of GAC-filtered water, 10 ng/L of spiked geosmin was completely masked by 0.15-0.1 mg/L of residual chlorine. Combined ozone and GAC was not enough to treat raw water spiked with 300 ng/L of geosmin. In this experiment, sensory analysts were able to detect earthy or musty odors from the treated water. From a masking experiment with raw water taken from the Daechung Reservoir, it was found that fishy odor was more difficult to mask with chlorine than earthy odor. As the chlorine residual declined, the analysts began to notice the original odor and the fishy odor was noticed earlier than the earthy odor.