Development of the slowly released molasses barrier system for controlling nitrate plume in groundwater
고체당밀로 구성된 관정형 반응벽체와 종속영양탈질을 이용한 지하수 내 질산염 제거에 관한 연구

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dc.description학위논문 (박사)-- 서울대학교 대학원 : 건설환경공학부, 2013. 2. 남경필.-
dc.description.abstractThis study was objected to identify the applicability of the well-type slowly released molasses barrier system (SRM system) as an in situ remedial technique to treat the nitrate-contaminated groundwater by the denitrifying activity of heterotrophic microbes. A SRM material, a solidifying molasses, was made using a molding technique by mixing the liquid phase molasses with paraffin wax, cellulose, and silica sands. This SRM material can continuously release molasses as a carbon source for indigenous heterotrophic denitrifiers over relatively long periods by the diffusion process with decreased release rates when it is placed into groundwater passing through. The developed SRM system could continuously deliver molasses into the groundwater over an extended period of time. Therefore, the SRM system could be an attractive long-term nitrate treatment option, showing nitrate removal efficiencies were estimated to be fairly high as ~85% and ~84% for nitrate of 89 and 142 mg L-1 in the column- and pilot-scale experiments. The removal efficiencies in the field experiment were relatively moderate at ~43% for nitrate of 320 mg L-1. Moderate nitrate removal efficiency in the field might have been caused by the heterogeneity/anisotropy of the aquifer and insufficient molasses dispersion to the denitrifiers. From result of the PCR-DGGE series, nitrite reductase gene fragments were amplified from uncultured isolates in pilot- and field soils, indicating a heterotrophic denitrifying capability in soil is common. Thus, the SRM system can be possibly applied into the nitrate contaminated groundwater with minor consideration for the existence of the denitrifying microbes in soils. Although many constraints related to the heterogeneous nature of aquifers exist, the SRM system can be a useful tool for control of dilute, large, and shallow nitrate contaminated groundwater plume. For achieving on-site remedial goals of the nitrate-contaminated groundwater in the targeted field, changes in the mixing rate of SRM constituents or its volume to prolong effective longevity can be readily modified. Further, the number and shape of the SRM barrier and the array of the SRM rods per a barrier can be changed for attaining remedial goals of the targeted contaminated field.-
dc.description.tableofcontentsChapter 1 Introduction 1
Chapter 1 Introduction 1
1.1 Background 1
1.2 Objectives 5
1.3 Dissertation structure 6
References 8

Chapter 2 Literature review 13
2.1 Organic compounds for denitrification 13
2.1.1 Sawdust 13
2.1.2 Natural calcareous materials 15
2.1.3 Wood chips 16
2.1.4 Organic acids 17
2.1.5 Molasses 18
2.2 Permeable reactive barriers 23
2.2.1 Biologic PRB system with sawdust 24
2.2.2 Biologic PRB system with sulfur granules 26
2.2.3 Biologic PRB system with molasses 28
References 33

Chapter 3 Denitrification by a heterotrophic denitrifier with the aid of the slowly released molasses 39
3.1 Introduction 39
3.2 Materials and methods 41
3.2.1 Isolation of a heterotrophic denitrifier 41
3.2.2 Identification of the denitrifying capacity 42
3.2.3 SRM manufacture and experimental setup 43
3.3 Results and discussion 45
3.3.1 Isolation of a heterotrophic denitrifier 45
3.3.2 Denitrifying capacity of the isolated denitrifier 47
3.3.3 Column test results using the SRM material 48
3.4 Conclusions 57
References 58

Chapter 4 Release characteristics of molasses from a well-type barrier system in groundwater: A large test tank study for nitrate removal 63
4.1 Introduction 63
4.2 Materials and methods 66
4.2.1 Preparation of the SRM rod and the SRM release test 66
4.2.2 Water sampling and chemical analysis 67
4.2.3 Model application 68
4.2.4 Boundary conditions 74
4.3 Results and discussion 78
4.3.1 SRM release test 78
4.3.2 Model simulation 80
4.3.3 Longevity of the SRM system 84
4.3.4 Suitability of model application 90
4.4 Conclusions 92
References 94

Chapter 5 The slowly released molasses barrier system for controlling nitrate plume: A large test tank study 99
5.1 Introduction 99
5.2 Materials and methods 102
5.2.1 Preparation of the SRM rods 102
5.2.2 Flow-tank setup and SRM system operation 102
5.2.3 Sample collection and chemical analysis 106
5.2.4 Identification of nitrate reductase and denitrifiers 107
5.3 Results and discussion 110
5.3.1 Nitrate removal efficiency 110
5.3.2 Remaining molasses concentrations 114
5.3.3 Actual nitrate removal and molasses consumption 118
5.3.4 Groundwater chemistry 131
5.3.5 Identification of the nirK gene and a denitrifier 132
5.4 Conclusions 136
References 137

Chapter 6 In situ microbiological denitrification using the slowly released molasses barrier system: A field application 143
6.1 Introduction 143
6.2 Materials and methods 151
6.2.1 Identification of nitrate reductase 151
6.2.2 Preparation of the SRM rods 152
6.2.3 Experimental setup 152
6.2.4 Sample collection and chemical analysis 153
6.3 Results and discussion 156
6.3.1 Nitrate removal efficiency 156
6.3.2 Remaining molasses problem 159
6.3.3 Cause of the low nitrate removal efficiency levels 160
6.4 Conclusions 166
References 168

Chapter 7 Conclusions 171
국문초록 173
dc.format.extent3443490 bytes-
dc.publisher서울대학교 대학원-
dc.subjectSRM system-
dc.subjectheterotrophic denitrification-
dc.subjectremoval efficiency-
dc.titleDevelopment of the slowly released molasses barrier system for controlling nitrate plume in groundwater-
dc.title.alternative고체당밀로 구성된 관정형 반응벽체와 종속영양탈질을 이용한 지하수 내 질산염 제거에 관한 연구-
dc.contributor.AlternativeAuthorByung Sun Lee-
dc.contributor.affiliation공과대학 건설환경공학부-
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Civil & Environmental Engineering (건설환경공학부)Theses (Ph.D. / Sc.D._건설환경공학부)
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