흡착형태에 따른 박테리아 운송에 관한 모델링 연구 = Modeling of bacterial transport in sandy soil using various sorption kinetics

국문 초록 (Abstract)

본 연구에서는 2가지 다른 형태의 배치시험 즉, 평형 및 비평형 배치 시험을 통하여 고액비에 따른 사질토양에서의 Pseudomonas aeruginosa의 평형 및 비평형 흡착 계수를 결정하였으며, 다양한 비평형 흡착조건에서의 합착 형태에 따른 미생물 운송기작을 비교 분석하였다. 평형 배치시험 결과 선형등온흡착 모델이 적용될 수 있었으며, 이 경우 분배계수(Kd) 및 지연계수(R)는 고액비 3 : 1과 1 : 3에서 각각 0.28 ㎖/g, 2.43 ㎖/g 및 2.11과 10.49로 나타났으며, 높은 고액비에서 분배계수는 8.7배, 지연계수는 5배 낮게 나타났다. 또한 비평형 배치시험에서 구한 비가역흡착계수()는 2.29×10-1/hr, 1.0/hr으로 그리고 흡착(1) 및 탈착(2) 계수는 각 고액비에서 9.85×10-2/hr, 7.99×10-2/hr 및 7.06×10-2/hr, 1.28×10-1/hr으로 나타났다. 배치시험을 통하여 획득된 파라미터를 흡착형태에 따른 다양한 운송 모델에 적용하여 실측치와 비교해본 결과, 주상시험 조건과 유사한 고액비(3 : 1)에서 결정된 비가역흡착계수와 흡착/탈착 계수를 이용한 가역/비가역 흡착 모델이 상대적으로 높은 일치도를 보였고, 미생물의 비가역 흡착에 의한 농도감소를 가장 잘 반영하였다.

다국어 초록 (Multilingual Abstract)

In this study we determined sorption parameters of Pseudomonas aeruginosa in sandy soil by conducting two different types of batch tests. Sorption batch tests were performed under both equilibrium and nonequilibrium(or kinetic) conditions using two different soil-to-solution ratios(3 : 1 and 1 : 3). The results of equilibrium sorption tests were fitted with a linear adsorption isotherm model yielding the distribution coefficient of the bacteria which was estimated 0.28㎖/g and 2.43㎖/g with the corresponding retardation factor of 2.11 and 10.49 for each soil-to-solution ratio respectively. High soil-to-solution ratio(3 : 1) showed the lower distribution coefficient(8.7 times) and retardation factor(5.0 times) than low soil-to-solution ratio(1 : 3). On the other hand, kinetic sorption data showed two-stage kinetic sorption with rapid adsorption at the initial period and slow adsorption at later period. Irreversible sorption coefficient() was estimated 2.29×10-1/hr and 1.0/hr at the rapid stage for both ratios respectively. The forward(1) and backward(2) sorption coefficients were found 9.85×10-2/hr and 7.99×10-2/hr, and 7.06×10-2/hr and 1.28×10-1/hr for both ratios respectively.
Modeling study revealed that irreversible sorption kinetics could best describe the bacterial transport in the sandy soil with significant reduction of bacterial peak in the column breakthrough data for the soil-to-solution ratio of 3 : 1.

목차 (Table of Contents)

• <List of figures>
• Figure 1. Schematic representation of the interrelationship of parameters and factors involved in the transport of bacteria through porous-medium aquifers(from Harvey, 1991)
• Figure 2. The fate and transport mechanisms of bacteria in a elemental volume of subsurface material(from Harvey, 1991)
• Figure 3. Survival test of Pseudomonas aeruginosa in MS medium
• Figure 4. Sorption isotherm for bacteria in sandy soil
• Figure 5. Kinetics of bacteria sorption in soil solution with different soil-to-solution ratios
• Figure 6. Sorption kinetics for bacteria measured with 3 : 1(●) and 1 : 3(○), fitted with equation
• Figure 7. Best fit of two-stage irreversible sorption model to bacteria sorption data
• Figure 8. Best fit of reversible sorption model to bacteria sorption data
• Figure 9. BTCs obtained from column tests
• Figure 10. Comparison of BTCs result between DI water and MS medium
• Figure 11. Comparison of fitting result with soil : solution - 3 :
• Figure 12. Comparison of fitting result with soil : solution - 1 :
• Figure 13. Comparison of irreversible fitting result with soil : solution - 3 :
• Figure 14. Comparison of reversible/irreversible fitting result with soil : solution - 3 :
• Figure 15. Comparison of fitting result with soil : solution - 3 :
• Figure 16. Comparison of irreversible fitting result with soil : solution - 1 :
• Figure 17. Comparison of reversible/irreversible fitting result with soil : solution - 1 :
• Figure 18. Comparison of fitting result with soil : solution - 1 :
• <List of tables>
• Table 1. Dimensionless parameters for the two-site model
• Table 2. Experimental conditions of column test
• Table 3. Distribution coefficients and retardation factors obtained from linear sorption isotherm model of bacteria
• Table 4. Parameters calculated from irreversible sorption model
• Table 5. Parameters calculated from two-stage irreversible sorption model
• Table 6. Dimensionless parameters calculated from two-stage irreversible sorption model
• Table 7. Dimensionless parameter calculated from two-stage irreversible sorption model
• Table 8. Parameters calculated from first-order reversible kinetic sorption model
• Table 9. Parameters calculated from Column test with CXTFIT
• Table 10. Parameters calculated from different kinetic sorption model
• Table 11. Sum of error squares of each model
• 목 차
• 요 약
• List of figures
• List of tables
• 1. 서 론
• 1.1. 연구 배경 및 필요성
• 1.2. 연구목적
• 2. 흡착이론과 운송방정식
• 2.1. 흡착이론
• 2.1.1. 평형흡착모델
• 2.1.1.1. Linear sorption isotherm
• 2.1.1.2. Freundlich sorption isotherm
• 2.1.1.3. Langmuir sorption isotherm
• 2.1.2. 비평형 흡착모델
• 2.1.2.1. Irreversible sorption model
• 2.1.2.2. Two-site sorption model
• 2.1.2.3. Reversible sorption model
• 2.2. 운송방정식
• 2.2.1. Equilibrium transport model
• 2.2.2. Non-Equilibrium transport model
• 2.2.2.1. Irreversible transport model
• 2.2.2.2. Two-site transport model
• 2.2.2.3. Reversible transport model
• 2.2.2.4. Reversible and Irreversible sorption transport model
• 3. 실험재료 및 방법
• 3.1. 실험재료
• 3.1.1. 미생물
• 3.1.2. 배지
• 3.1.3. 토양 시료
• 3.2. 실험방법
• 3.2.1. 미생물 배양
• 3.2.2. 평형 배치시험
• 3.2.3. 비평형 배치시험
• 3.2.4. 주상 시험
• 3.2.5. Parameter 추정
• 4. 결 과
• 4.1. 평형 배치시험
• 4.2. 비평형 배치시험
• 4.3. 주상 시험
• 4.4. 주상 시험과 모델링 결과와의 비교
• 5. 결 론
• 참고문헌