• 한국지하수토양환경학회지:지하수토양환경
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• 제15권1호
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• pp.1-8
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• 2010

Cometabolic air sparging (CAS) is a new and innovative technology that uses air sparging principles but attempts to optimize in situ contaminant degradation by adding a growth substrate to saturated zone. CAS relies on the degradation of the primary growth substrate and cometabolic substrate transformation in the saturated zone and in the vadose zone for volatilized contaminants. In this study, we have investigated to determine MTBE degradation pattern and microbial activity variation if using propane as a primary substrate at the condition of considering air injection rate and air injection pattern. Laboratory-scale two-dimentional aquifer physical model studies were used and the experimental results were represented that the optimal conditions were as air injection rate of 1,000 mL/min and pulsed air injection pattern (15 min on/off). Over 1,000 mL/min air injection rate and continuous air injection pattern was no affected to increase DO concentration. On the other hand, Injection of propane and propane-utilizing bacteria degraded MTBE partially. And also, injection of propane- and MTBE-utilizing bacteria effectively degraded MTBE and TBA production was observed.

• Journal of Microbiology and Biotechnology
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• 제15권4호
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• pp.859-865
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• 2005

The stimulatory effects of exogenous salicylate as a pathway inducer on phenanthrene biodegradation were investigated using Burkholderia cepacia PM07. The phenanthrene degradation rate was greatly enhanced by increasing the salicylate additions, and the maximum rate was 19.6 mg $I^{-1}\;d^{-1}$ with the addition of 200 mg $I^{-1}$ of salicylate, 3.5 times higher than that (5.6 mg $I^{-1}\;d^{-1}$) without the addition of salicylate. The degradation rate was decreased at higher concentrations of salicylate (above 500 mg$I^{-1}$), and cell growth was significantly inhibited. The phenanthrene degradation was not affected by increasing glucose up to 2 g $I^{-1}$, although dramatic microbial growth was obtained. The stimulatory effect of exogenous salicylate decreased in the presence of glucose. After the addition of 200 mg $I^{-1}$ of salicylate, approximately $60\%$ of the initial phenanthrene (50 mg $I^{-1}$) was degraded after 96 h. However, with extra addition of 200 mg $I^{-1}$ of glucose, the phenanthrene degradation rate decreased, and only $18.5\%$ of the initial phenanthrene was degraded.

• Journal of Microbiology and Biotechnology
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• 제12권4호
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• pp.695-698
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• 2002

The biodegradation of 2,4,6-trinitrotoluene (TNT) was performed on a laboratory scale using P. putida originally isolated from explosive-contaminated soil. One hundred mg/1 of TNT was completely degraded within 20 h under optimum conditions. Various supplemental energy sources (carbon sources, nitrogen sources, and surfactant) were tested, with the main objective of identifying an inexpensive source and enhancing the degradation rate for large-scale biodegradation. Based on the degradation rate, molasses was selected as a possible supplemental carbon source, along with NH$_4$Cl and Tween 80 as a nitrogen source and surfactant, respectively. The degradation rate increased about 3.3 fo1d when supplemental energy sources were added and the degradation rate constant increased from 0.068 h$\^$-1/ to 0.224 h$\^$-1/. These results appear to be promising in application of the process to TNT-contaminated soil applications.

• 품질경영학회지
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• 제32권1호
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• pp.113-129
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• 2004

The reliability of the product can be improved by making the product less sensitive to noises. Especially, it Is important to make products robust against various noise factors encountered in production and field environments. In this paper, the phenomenon of degradation assumes a simple random coefficient degradation model to present analysis procedures of degradation data for robust experimental design. To alleviate weak points of previous studies, such as Taguchi's, Wasserman's, and pseudo failure time methods, novel techniques for analysis of degradation data using the cross array that regards amount of degradation as a dynamic characteristic for time are proposed. Analysis approach for degradation data using robust experimental design are classified by assumptions on parametric or nonparametric degradation rate(or slope). Also, a simulation study demonstrates the superiority of proposed methods over some previous works.

• 한국환경농학회지
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• 제29권4호
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• pp.396-401
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• 2010

살균제 tolclofos-methyl은 인삼 및 인삼 경작지 토양에서 빈번히 검출되고 있어 그 안전성이 문제시되고 있다. 이에 tolclofos-methyl을 토양 slurry조건에서 여러 종류의 화학적 처리를 통하여 분해되는 정도를 조사하였다. ZVI를 처리한 경우 uZVI가 aZVI보다 tolclofos-methyl의 분해를 촉진 하였으며 uZVI와 ZVZn의 경우에는 ZVZn가 더 촉진시키는 것으로 나타났다. uZVI와 ZVZn 처리구에서는 처리량이 증가할수록 그리고 입경이 작을수록 더 잘 분해되는 것으로 나타났다. pH 4.0 이하의 산성 조건하에서 처리된 ZVI는 tolclofos-methyl의 분해를 더욱 촉진시켜 수용액에서 24시간 만에 94.4%까지 분해시켰다. Fenton 반응을 이용한 tolclofos-methyl의 분해는 iron source로 $Fe_2(SO_4)_3$가 가장 효과적이었으며, $H_2O_2$ 500 mM 처리구에서 93.5%까지 분해되었다. Sodium bisulfite를 이용한 토양 slurry 중의 tolclofos-methyl의 분해는 처리량이 증가할수록 분해가 촉진되었으며 50 mM 처리구에서 52.9%가 분해되었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권6호
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• pp.43-51
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• 2012

Rreactivity of persulfate (PS) for oxidation of TCE under various conditions such as heat, $Fe^{2+}$, and UV was investigated. It was found that degradation rate of TCE increased with increasing temperature from 15 to $35^{\circ}C$. At pH 7.0, the rate constants (k) at 15, 25, 30, and $35^{\circ}C$ were 0.07, 0.30, 0.74, and $1.30h^{-1}$, respectively. For activation by $Fe^{2+}$, removal efficiency of TCE increased with increasing $Fe^{2+}$ concentration from 1.9 mM to 11 mM. The maximum removal efficiency of TCE was approximately 85% when pH of the solution dropped from 7.0 to 2.5. Degradation of TCE by UV-activated PS was the most effective, showing that the degradation rate of TCE increased with inreasing PS dosage; the rate constants (k) at 0.5, 2.5, and 10 mM were 34.2, 40.5, and $55.9h^{-1}$, respectively. Our results suggest that PS activation by UV/PS process could be the most effective in activation processes tested for TCE degradation. For oxidation process by PS, however, pH should be observed and adjusted to neutral conditions (i.e., 5.8-8.5) if necessary.

• 한국환경과학회지
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• 제23권5호
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• pp.963-972
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• 2014

In this study, ibuprofen(IBP) degradation by the photochemical ($UV/S_2O{_8}^{2-}$) and sonochemical ($US/S_2O{_8}^{2-}$) processes was examined under various parameters, such as UV ($10{\sim}40{\pm}5W/L$) and US ($50{\sim}90{\pm}5W/L$) power density, optimum dosage of persulfate ion ($S_2O{_8}^{2-}$), temperature ($20{\sim}60^{\circ}C$) and anions effect ($Cl^-$, $HCO_3{^-}$, $CO{_3}^{2-}$). The pseudo-first-order degradation rate constants were in the order of $10^{-1}$ to $10^{-5}min^{-1}$ depending on each processes. The synergistic effect of IBP degradation in $UV/S_2O{_8}^{2-}$ and $US/S_2O{_8}^{2-}$ processes could investigated, due to the generation of $SO_4{^-}$ radical. This result can confirm from the produced $H_2O_2$ and $SO{_4}^{2-}$ concentration in each processes. IBP degradation rate affected by the $S_2O{_8}^{2-}$ dosage, temperature, power and anion existence parameters. In particular, IBP degradation rate increased with the increase of the temperature ($60^{\circ}C$) and applied power density (UV:$40{\pm}5W/L$, US:$90{\pm}5W/L$). On the other hand, anions effect on the IBP degradation was negative, due to the anion play as a the scavenger of radical.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.431-436
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• 2002

Effects of fertilizer additions for oil degradation were examined in sand seashore mesocosms. Within 37 days, up to $85\%$ removal was achieved by the addition of slow-release type fertilizer (SRF) with the initial degradation rate of 423.3 mg oil $(kg sand)^-1\;day^-1$. The removal was mostly of biological origin based on the changes of $C_17$ /pristane and $C_18$/phytane ratios from 2.60 to 0.81 and from 3.55 to 1.29, respectively. The addition of oleophilic fertilizer (Inipol EAP22) was less effective and resulted in the removal of $64\%$ of the added oil ($3\%$, v/v) with a lower initial degradation rate. Petroleum-degrading bacteria had achieved a value of $1{\times}10^8$ CFU $(g sand)^-1$ at Day 3 and this peak exactly coincided with the initial degradation in the SRF-treated mesocosm. In this mesocosm, surface tension values were decreased drastically during Days 3 and 8, suggesting that microbially-produced surface-active agents actively enhanced the oil degradation rate and cell proliferation. Although the Inipol-treated mesocosm appeared to show significantly enhanced oil degradation compared to that of the untreated control mesocosm, Inipol was found to be less effective than SRF in enhancing a true oil-degrader when compared under similar experimental conditions.

• Asian-Australasian Journal of Animal Sciences
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• 제17권1호
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• pp.53-62
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• 2004

The aim of this study was to predict the energy value and dynamic degradation of roughage in Taiwan using the $Daisy^{(R)}$. in vitro fermentation method to provide information on one of the very important nutrients for ration formulation. The second objective was to study the effects of Aspergillus oryzae (AFE) inclusion on nutrient utilization. Three ruminal fistulated dry dairy cows were used for rumen fluid and fifteen conventional forages used in dairy cattle were collected around this island. The degradability of these feedstuffs with and without AFE ($Amaferm^{(R)}$.) treatment was measured using the $Daisy^{(R)}$. in vitro method. The roughage energy values, including TDN and NEL, were calculated according to Robinson (2000). Results from the 30 h in vitro neutral detergent fiber (NDF) degradability and predicted energy evaluations showed that alfalfa (among the forages) contained the highest degradability and energy values, Bermuda straw having the lowest. Peanut vines and corn silage contained higher energy values and the lowest value found in Pangola and Napier grasses among the locally produced forages. Pangola and Napier grasses had lower values than most imported forages except Bermuda straw. Among the by-products, wheat middling contained the highest NDF degradability, while rice bran contained the richest energy value due to its high oil content. From the dynamic dry matter (DM), organic matter (OM), acid detergent fiber (ADF) and neutral detergent fiber (NDF) degradation, corn silage contained the highest effective degradation among the local forages; wheat middling (among the by-products) degraded the fastest in DM, OM, ADF and NDF and showed the highest effective degradability. AFE inclusion was inconsistent among the forages. Alfalfa hay showed significantly increased 30 h NDF degradability and energy values, Pangola hay, Napier grass and brewer's grains showed decreased degradability and energy values. AFE inclusion increased the DM, OM and NDF degradation rate in most forage, but only increased the DM degradation rate in sorghum distiller's grains, the OM degradation rate in bean curd pomace and the NDF and ADF degradation rates in soy pomace (among the by-products).

• KSBB Journal
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• 제14권4호
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• pp.452-459
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• 1999

본 연구에서는 난분해성 물질인 기상의 TCE를 효과적으로 처리하기 위하여 CSTR과 TBR을 연결한 2단계 생물막 반응기를 제작ㆍ운전하였다. TBR에는 TCE 분해능이 탁월한 메탄자화균인 Methylosinus trichosporium OB3b를 활성탄에 고정화시켰고, 기상의 TCE를 유입부에 연속적으로 공급하여 분해시켰다. 개발된 반응기 시스템의 효율을 조사하기 위해 다양한 운전조건에서 TCE 분해속도, TCE 전화율 및 cMMO 활성변화 등을 조사하였다. 여러 가지의 유입부 TCE 농도에서 운전한 결과 80 $\mu$mol/L의 고농도까지 처리가 가능함을 알 수 있었고, TCE를 포함한 기체의 유속을 변화시켰을 때 유속이 증가함에 따라 낮은 유속(50~200 mL/min)에서는 직선적으로 TCE를 분해속도 및 전화율이 증가하다가 높은 유속(200~600 mL/min)에서는 일정하게 유지되었다. TBR의 온도를 달리하였을 때, 2$0^{\circ}C$의 낮은 온도에서 3$0^{\circ}C$의 높은 온도보다 TCE 전화율 및 분해속도가 증가되어 TBR에서의 TCE 분해반응이 물질전달 저해를 받음을 알 수 있었다. CSTR에서의 희석속도가 낮으면 TCE 분해속도와 전화율의 감소 및 sMMO 활성 저하 현상이 일어남을 관측할 수 있었고, TBR에서 TCE 분해 과정에서 불활성화된 sMMO 및 세포 활성을 효과적으로 재활성화시키기 위해서는 CSTR의 희석속도를 높이 유지해야함을 알 수 있었다. 약 270일 이상의 운전기간 동안 운전조건을 다양하게 변경시켜도 매우 안정되게 시스템이 유지됨을 알 수 있었고, 최고분해속도는 525 mg TCE/Lㆍday 정도로 높아 개발된 2단계 CSTR/TBR 시스템의 우수성을 알 수 있었다.