Physical Aquifer Model(PAM)을 이용한 불균질 대수층 내 계면활성제 이송에 관한 연구 = Evaluate Surfactant Transport characteristics in the Heterogeneous Aquifer by Physical Aquifer Model(PAM)

다국어 초록 (Multilingual Abstract)

A typical groundwater contaminant, petroleum hydro-carbons have low solubility and high affinity to solid phase. In addition, the petroleum hydro-carbons form free-products in the result of variation of groundwater level in aquifer, or it is adsorbed on the soil particle with high concentration. Therefore, the contaminants are working as a source of long-term groundwater contamination because the contaminant is dissolved to groundwater with slow desorption from soil. Surfactant is the most commonly used to remove the contaminants in aquifer.

The mechanism to remove contaminants with surfactant is injecting water, contains surfactant into the aquifer to enhance solubility of contaminants absorbed in soil or remained as residual LNAPL in groundwater. Then the contaminant is dissolved into surfactant, and it is extracted for consequent on-site treatment. However, surfactant flushing process is difficult to apply to low permeable aquifer. Surfactant causes decline of permeability in contaminated site due to decrease of porosity. Furthermore, the process reduces the mobility of contaminant because of interaction between soil and surfactant.

Surfactant flushing process requires lab-scale experiment for assessing feasibility application in the contaminated site because the process is more affected by hydro-geological factors than characteristics of contaminant. But, it is difficult to estimate the feasibility by conventional batch experiments.

Therefore, PAM(Physical Aquifer Model) was adapted to perform experiments which can demonstrate various and complicated geochemical heterogeneous aquifer conditions. Using the PAM, push-pull tests were performed to figure out the characteristics of flow and petroleum flushing.

PPTTs showed that concentration of bromide in permeable layers(W2_1,W2_3) were more than 95% of injected concentrations whereas concentration in low permeability layer(W2_2) was about 40% after injecting same volume of test solute. The results may be caused by not only different hydraulic conductivity, but also vertical mobility caused by higher hydraulic conductivity of sand pack around well than aquifer. Consequently, we expected that solute in low permeability layer will have vertical mobility no matter what solute is injected into the aquifer. Also, PPTTs results showed that the recovery rates of bromide, toluene, DO, and surfactant were 58%, 47%, 47%, and 17%, respectively. The results from above experiments showed high absorption characteristics of the surfactant on the soil particle.

In addition, the recovery rates of toluene from PPSFT(Ⅰ), PPSFT(Ⅱ), and PPASFT were 15%, 107%, 38% respectively. As a result, the toluene recovery rate was proportional to the amount of injected surfactant, but the excessive injection of surfactant caused decrease of toluene recovery rate because toluene was immobilized on the surfactant absorbed on soil particle.

It is considered that further study about hydro-geological characteristic of aquifer and surfactant for effective remediation in contaminated site with petroleum is required.

목차 (Table of Contents)

• 1. 서론 1
• 1.1 연구 배경 1
• 1.2 연구 목적 1
• 2. 문헌 연구 3
• 2.1 계면활성제를 이용한 세정 3
• 2.1.1 계면활성제 세정 메커니즘 3
• 2.1.2 탄화수소 오염 지하수 계면활성제 세정 사례 8
• 2.2 탄화수소의 성상 및 생분해 10
• 2.2.1 벤젠 (Benzene), 톨루엔 (Toluene), 에틸벤젠 (Ethylbenzene),
• 크실렌(xylene)의 물리․화학적 특성 10
• 2.2.2 Total Petroleum Hydrocarbon (TPH)의 물리․화학적 특성 12
• 2.2.3 BTEX 생분해 메커니즘 16
• 2.3 유류오염 지하수 생물학적 복원 사례 23
• 3. PAM 제작 및 주입∙추출장비 설치 방법 26
• 3.1 PAM 제작 목적 26
• 3.2 PAM 제작 및 실험 준비 26
• 3.2.1 PAM의 이론적 배경 26
• 3.2.2 PAM 제작 28
• 3.2.3 토양 충전 30
• 3.2.4 시료 채취관 설치 31
• 3.2.5 피조미터 설치 32
• 3.3 주입 장비 34
• 3.4 PAM 포화층 구성 36
• 4. Push-Pull Test (PPT) 방법 및 분석 39
• 4.1 Push-pull test 이론적 배경 39
• 4.2 PPT 실험 순서 및 구성 40
• 4.3 PPT 방법 42
• 4.3.1 PPTT (I) 42
• 4.3.2 PPTT (II) 44
• 4.3.3 PPSFT (I) 45
• 4.3.4 PPSFT (II) 45
• 4.3.5 PPABT 방법 45
• 4.3.6 PPASFT 방법 46
• 4.4 시료 분석 방법 46
• 4.4.1 톨루엔 분석 46
• 4.4.2 계면활성제 분석 46
• 4.4.3 브로마이드 분석 47
• 4.4.4 DO 분석 47
• 4.5 수리전도계수 산출 방법 48
• 4.6 분석결과 해석 52
• 5. Push-Pull Test (PPT) 실험결과 54
• 5.1 PPTT 결과 54
• 5.2 PPSFT 결과 64
• 5.3 PPABT 결과 73
• 5.4 PPASFT 결과 76
• 6. 결론 80
• 7. 참고문헌 81
• 부록(Ⅰ) 톨루엔 호기성 분해 Energetics 계산 87