Odor compounds and air-born microorganisms are simultaneously emitted from various aeration processes such as aerobic digestion, food-waste compositing, and carcass decomposition facilities that are biologically-treating wastes with high organic contents. The air streams emitted from these processes commonly contain sulfur-containing odorous compounds such as hydrogen sulfide(H2S) and bacterial bioaerosols. In this study, a wet-plasma method was applied to remove these air-born pollutants and to minimize safety issues. In addition, the effects of a gas retention time and a liquid-gas ratio were evaluated on removal efficiencies in the wet-plasma system. At the gas reaction time of 1.8 seconds and the liquid-gas ratio of 0.05 mLaq/Lg, the removal efficiency of bioaerosol was approximately 75 %, while the removal efficiency of H2S was lower than 20 %, indicating that the gaseous compound was not effectively oxidized by the plasma reaction at the low liquid addition. When the liquid-gas ratio was increased to 0.25 mLaq/Lg, the removal efficiencies of both H2S and bioaerosol increased to greater than 99 %. At the higher liquid-gas ratio, more ozone was generated by the wet-plasma reaction. The ozone generation was significantly affected by the input electrical energy, and it needed to be removed before discharged from the process.

영양염류의 농도와 수리학적체류시간에 따른 달뿌리풀의 질소ㆍ인 흡수 실험 결과로서 NH4-N, NO3-N, PO4-P의 흡수량은 각각 체류시간에 따라 유의한 영향을 미쳤으며(F=44.93, 95.52, 12.70, Pm2, 평균 수질농도 0.308 NH4-N, 1.461 NO3-N, 0.348 PO4-P mg/L, 체류시 간 1일~ 5일 범위에서 1 m2 1일 기준의 흡수량이 각각 7.31~20.15 NH4

In this study, to analyze the change of mass of concrete structure subjected to fire damage, cement paste was exposed at high temperature to maintenance time and analyzed mass change characteristics by TGA analysis. As a result of analysis, the mass reduction rate of cement paste decreased with increasing heating time after heating at high temperature.

The mechanism of micro-bubble generation with a pump is not clarified yet, so the design of water treatment systems with a micro-bubble generating pump is based on trial and error methods. This study tried to explain clearly quantitative relationships of experimental micro-bubble concentration (Cair) of continuous operation tests with a micro-bubble generating pump and theoretical air solubility. Operation parameters for the tests were discharge pressure (Pg), water (Qw0) and air (q0) flow rates, orifice diameter (DO), and retention time (t). The experimental micro-bubble concentrations (Cair) at 4.8 atm of discharge pressure (Pg) were in the range of 21.04 to 25.29 mL/L. When the retention time (t) by changing the pipe line length (LP) increased from 1.22 to 6.77s, the experimental micro-bubble concentrations (Cair) increased from 25.86 to 30.78 mL air/L water linearly. The dissolved and dispersed micro-bubble concentrations (Cair) are approximately 4 times more than the theoretical air solubility.

Seaweeds are received high attending as one of new and renewable energy sources. In this study, the effects of organic loading rate (OLR) and hydraulic retention time (HRT) on anaerobic digestion with Laminaria japonica were investigated using labrotory-scale semi-continuous stirred type reactors. The results demonstrated that anaerobic digestion of Laminaria japonica performed stably with OLRs in the range of 1.00 ~ 1.50 g-VS/L⋅d and HRTs in the range of 27 ~ 40 days. The maximum methane production obtained was 251.33 mL-CH4/L⋅d, which was achieved for an OLR of 1.50 g-VS/L⋅d and a HRT of 27 days. However, an OLR of 1.75 g-VS/L⋅d and a HRT of 23 days brought about a decrease in the pH and volatile fatty acids (VFAs) accumulation, causing the destabilization of the reactor and process failure. The reactors operated at a constant influent substrate concentration, i.e., 40 g-VS/L, thus OLR and HRT could not be treated separately and independently. According to the limited results of this study, it seems that the suitable OLR of anaerobic digestion of Laminaria japonica was lower than 1.50 g-VS/L⋅d and suitable HRT was higher than 27 days.

하수에는 유기물, 질소, 인, 중금속 등 다양한 종류의 오염물질이 함유되어 있으며, 수계로 미처리하여 방류되게 되면 수계 수질을 악화시키게 된다. 그 중 질소(Nitrogen)와 인(Phosphorus)은 영양염류(Nutrient)로 분류되며 수계 부영양화(Eutrophication)의 주요한 원인으로 알려져 있다. 생물학적 영양소 제거 방법은 화학적 처리 방법에 비해 경제적, 환경적 및 운영적 장점을 가지고 있어 대부분의 하수처리에 적용되고 있다. 하지만, 현재 적용되는 기술에서는 암모니아성 질소를 질산성 질소 상태로 산화시킨 후 탈질 반응을 거치는 완전질산화(Nitrification)반응이 적용되고 있다. 만약 아질산성 질소 상태에서 탈질을 유도하는 아질산화 반응(Nitritation)을 적용하게 된다면, 완전질산화에 비해 이론적으로 약 25%의 산소를 절감할 수 있는 효과를 기대할 수 있다. 본 연구에서는 하수처리장에서 슬러지 처리 공정 중 혐기 소화단계에서 발생하는 고농도 질소를 함유한 혐기 소화 상징액을 대상으로 하여, SRT가 암모니아성 질소 제거율(Ammonium nitrogen removal rate)와 아질산화율(NItrite conversion rate)에 미치는 영향에 대한 연구를 수행하였다. 서울 A 하수처리장의 혐기 소화 상징액을 대상으로 한 실험실 규모 아질산화 반응조 운전 결과 안정적인 암모니아성 질소 제거율을 기대하기 위해서는 SRT 0.5d 이상, 고효율의 아질산화율을 기대하기 위해서는 SRT 1d를 유지해야 하는 것으로 나타났다. 이는 암모니아성 질소 제거율의 경우 일정한 SRT 이상 유지시켜 주면, 안정적인 효율을 기대 할 수 있는 반면, 아질산화율의 경우에는 일정한 SRT를 유지시켜 주어야만 안정적인 효율을 얻을 수 있는 것으로 해석 할 수 있다. 따라서 암모니아성 질소 제거 및 아질산화 반응에 서 SRT는 그 효율 및 유도에 있어 매우 중요한 인자로 작용하는 것을 확인 할 수 있다.