Hydraulic modeling and optimization of waste stabilization pond design for developing nations

•   Title page – – – i         Declaration – – – – ii                   Certification – iii         Dedication – iv         Acknowledgements – – – – – v         Table of Contents – – viii         List of Plates – – – xv         List of Figures – – xvi         List of Tables – xxiv         Abbreviations and symbols – – – xxvii         Abstract – – – – xxxiiChapter 1:   Introduction – – 1 11     Background to the study – 1 12     Problem statement – – – – 5     13     Aim of the research – 6 14     Objectives – 6 15     Scope of study – – – 6 16     Justification of study – 7 17     Limitation of the work – – – – 7  

Chapter TWO

LITERATURE REVIEW

• – 8     21   The pressure on water demand 8     22   Wastewater treatment systems in use – – – – 9     23   Waste stabilization ponds – 11 231   Treatment units in Waste Stabilization Ponds – – – 12           232   Anaerobic ponds – 13             232 1 Design approach for anaerobic pond15             233   Facultative ponds – – – – 17             2331 Design criteria for facultative pond – – – 17               2332 Surface BOD loading in facultative ponds – – – 19         234 Model approaches for faecal coliform prediction in facultative pond – – 20             2341 Continuous stirred reactor (CSTR) model approach21                 2342 Dispersed flow (DF) model approach – – – 23         235 Maturation Pond24     24 Waste Stabilization Ponds in Some Selected Institutions in Nigeria – 26             241   Waste stabilization pond in University of Nssuka, Nigeria – 29             242   Waste stabilization pond in Obafemi Awolowo University,                             Ile-Ife, Nigeria – 30               243   Waste stabilization pond in Ahmadu Bello University, Zaria,                             Nigeria – 32   25   Residence time-models in waste stabilization ponds – – – 35                 251 Plug flow pattern – 35                 252 Completely mixed flow pattern – – – – 37                 253 Dispersed hydraulic flow regime – – – – 39   26 Wind effect and thermo-stratification on hydraulic flow regime – 42   27 Tracer experiment43   28 Effects of baffles on the performance of waste stabilization – – 44   29 Computational Fluid Dynamics Approach to Waste Stabilization Ponds – – – 48   210 Laboratory scale ponds – – – – 56   211 Optimization of waste stabilization pond design – – – 59     212 Summary of literature review – – – – 61    

Chapter THREE

SYSTEM DESIGN AND IMPLEMENTATION

• – – – 62   31   Description of the study area – – – – 62 32   Collection of data on Water demand – – – – 65   33   Estimation of wastewater generated – – – – 66   34   Study of existing wastewater treatment system – – – 66   35   Analysis of wastewater samples70   36   Design of the laboratory-scale plant layout – – – – 70                   361 Design Guidelines for the University, Ota – – – 73                         3611 Temperature (T) – – – – 73                         3612 Population (P) – – – – 73                         3613 Wastewater generation (Q) and Design for 20 years period – 73                         3614 BOD Contribution per capita per day (BOD) – – 73                         3615 Total Organic Load (B) – – – 74                         3616 Total Influent BOD Concentration (Li) – – – 74                         3617 Volumetric organic loading (λv) – – – 74                         3618 Influent Bacteria Concentration (Bi) – – 74                         3619 Required effluent standards – – – 74 37   Waste stabilization pond design – 75             371 Design of Anaerobic Pond – – – – 75             372 Design of Facultative pond76             373 Design of Maturation Pond77 38 Design of Laboratory scale model – – – – 79             381 Modeling of the Anaerobic Laboratory-scale pond – – 79                 382 Modeling of the Facultative Laboratory-scale pond – – – 81             383 Modeling of the Maturation Laboratory-scale pond – – – 82  39 Laboratory Studies – – 85             391 Construction of the laboratory-scale waste stabilization ponds – 85             392 Materials used for the construction of the inlet and outlet structures – 86             393 Design of inlet and outlet structures of the WSP – – – 91             394 Operation of the Laboratory-Scale waste stabilization pond – – 94             395 Sampling and data collection – – – 95                 3951 Water temperature – – – 95                 3952 Influent and effluent samples – – – 95 310   Laboratory methods – 95           3101     Feacal coliform – 96           3102     Chloride – 96           3103     Sulphate – 96           3104     Nitrate – – 96           3105     Phosphate – 96           3106     Total Dissolved Solids – – – – 96           3107     Conductivity – 97           3108     pH – 97 311   Tracer Experiment – – 97               3111   Determination of First Order Kinetics (K value) for Residence time                           distribution (RTD) characterization – – – 99               3112   The gamma extension to the N-tanks in series model approach – 101 312   Methodology and application of Computational Fluid Dynamics model – 103           3121 Introduction 103           3122 CFD Model Application – – – – 106                       31221 Simulation of fluid mechanics fecal coliform inactivation 106                       31222 Constants used in the application modes – – 109                       31223 Mesh generation for the computational fluid dynamics model110                           31224 Model test for the simulation of residence time distribution                                     curve in the CFD – – – 113                     31225 Model test for the simulation of faecal coliform inactivation in                                     the unbaffled reactor – – – – 114                     31226 Model test for the simulation of faecal coliform inactivation in                                     the baffled reactors – – – 116             3123 Application of segregated flow model to compare RTD prediction                         and the CFD predictions for feacal coliform reduction – 122             3124 Summary of the CFD model methodology – – – – 124   3131 Optimization methodology and application – – – 125                 31311 Integration of COMSOL Multiphysics (CFD) with                             ModeFRONTIER optimization tool – – – 125 31312 The workflow pattern – – – – 126             31313 Building the process flow – – – 127             31314 Creating the application script – – 128             31315 Creating the data flow – – – – 129             31316 Creating the template input – – – 130             31317 Mining the output variables from the output files – 131 3132 Defining the goals – – – – 132             31321 The Objective functions for the optimization loop – – 132             31322 The constraints for the optimization loop – – – 133             31323 Cost objective Optimization – – – – 133             31324 The DOE and scheduler nodes set up136             31325 Model parameterization of input variables – – – 137               31326 DOE Algorithm – 140             31327 Simplex algorithm – 140               31328 Multi-Objective Genetic Algorithm II (MOGA-II) – – – – 141             31329 Faecal coliform log-removal for transverse and longitudinal                             baffle arrangements143     3133 Sensitivity Analysis on the model parameters – – – 145           3134 Running of output results from modeFRONTIER with the CFD tool – – 146     3135 Summary of the optimization methodology – – – – 146  

Chapter FOUR

SYSTEM TESTING AND EVALUATION

• Modeling results and Analysis       41 Model results for the RTD curve and FC inactivation for unbaffled reactors – 147       42 Initial Evaluation of baffled WSP designs in the absence of Cost using CFD151         421 Application of segregated flow model to compare the result of RTD                   prediction and the CFD predictions for feacal coliform reduction – 163     43 Results of the N-Tanks in series and CFD models – – – 166       431 General discussion on the results of the N-Tanks in series and CFD                 Models – 173   44 Results of some selected simulation of faecal coliform inactivation for 80%             Pond-width baffle Laboratory- scale reactors – – – 176 45 Optimization model results – 181       451 The single objective SIMPLEX optimization configuration results – 181       452 The Multi-objective MOGA II optimization configuration results – 195         453 Scaling up of Optimized design configuration – – 216                 4531 Scaling up of Anaerobic Longitudinal baffle arrangement – – 216                 4532 Scaling up of Facultative Transverse baffle arrangement – 218                 4533 Scaling up of Maturation Longitudinal baffle arrangement – 219                 4534 Summary of results of scaling up of design configuration – 220       454 Results of sensitivity analysis for Simplex design at upper and lower                   boundary – 220     455 Results of sensitivity analysis for MOGA II design at upper and lower                       boundary – 235     456 Summary of the optimization model result – – – – 249  

Chapter FIVE

SUMMARY, CONCLUSION AND RECOMMENDATIONS

• Laboratory-Scale WSP post-modeling results and verification of the                     Optimized models – – – – 250 51 Introduction – 250 52 Microbial and physico-chemical parameters – – – 251       521 Feacal coliform inactivation in the reactors – – – 251     522 Phosphate removal256     523 Chloride removal – – – – 258     524 Nitrate removal – – – – 259     525 Sulphate removal – – – – 260     526 pH variation265     527 Total dissolved solids removal – – – 266     528 Conductivity variation – – – – 266     529 Summary of laboratory experimentation – – – 267   Chapter 6: Discussion of results – – – – 269         61 Experimental results of Laboratory-scale waste stabilization ponds                 in series – 269 62 Hydraulic efficiency of CFD model laboratory-scale waste stabilization               ponds in series – 270         63 Optimization of laboratory-scale ponds by Simplex and MOGA II                 Algorithms – 274         64 Summary of discussion – – – – 275   Chapter 7: Conclusions and recommendations for further work – 277         71 Conclusions277         72 Contributions to knowledge – – – 278         73 Recommendation for further work – – – 279   References – 280     Appendix A – 298   A1     COMSOL Multiphysics Model M-file for Transverse baffle             anaerobic reactor – – – – , – 298   A2     COMSOL Multiphysics Model M-file for longitudinal baffle             anaerobic reactor – 302   A3     COMSOL Multiphysics Model M-file for Transverse baffle             facultative reactor306   A4     COMSOL Multiphysics Model M-file for longitudinal baffle               facultative reactor – – – – 310   A5     COMSOL Multiphysics Model M-file for Transverse             Maturation reactor – – – – 314   A6     COMSOL Multiphysics Model M-file for longitudinal           Maturation reactor – – – – 318   Appendix B322 B1     Transverse baffle arrangement scripting – – – 322 B2     Longitudinal baffle arrangement scripting – – 324List of Plates Plate 31       Tanker dislodging wastewater into the treatment chamber – – 67 Plate 32       The water hyacinth reed beds showing baffle arrangement                         at opposing edges68 Plate 33       The inlet compartment showing gate valve – – 68 Plate 34       The Outfall waterway leading into the valley below the cliff – 69 Plate 35       Effluent discharging through the outfall into the thick                       vegetation valley – – – – 69 Plate 36       Front view of the laboratory-scale pond – 88 Plate 37       Areal view of the laboratory-scale pond close to source of sunlight – – 88 Plate 38       An elevated tank serving as reservoir – 89 Plate 39       Inlet-outlet alternation of laboratory-scale WSP – – 89 Plate 310     Laboratory-scaled anaerobic ponds – – – 90 Plate 311     Laboratory-scaled facultative ponds – – – 90 Plate 312     Laboratory-scaled maturation ponds – – – 91 Plate 313       Inlet and outlet structure of the laboratory-scale                         waste stabilization pond – – – 92 Plate 314     Two 25-mm PVC hoses linked with the T-connector – – 92 Plate 315     Control valves screwed to position for wastewater flow – 93 Plate 316     Outlet structures connected to two pieces of ½ inch hoses                       for effluent Discharge – – – – 93 Plate 317     Tracer experiment with Sodium Aluminum Sulphosilicate – – 97 Plate 318     Tracer chemical diluting with the wastewater before                       getting to the outlet – – – – 98 Plate 319     Improvement in wastewater quality along the units – – 98List of Figures Figure 21     Waste stabilization pond configurations                                                   12 Figure 22     Operation of the Anaerobic Pond                                                               14 Figure 23     Operation of the facultative pond                                                               23 Figure 31     Bar chart of staff and student population trend                                         63 Figure 32     Template for calculating the per-capita water use                                     65 Figure 33     A sketch of the laboratory-scale WSP and operating conditions               72 Figure 34     Configuration of the designed WSP for Covenant University                 79 Figure 35     Different baffle arrangements with 70% pond width                           anaerobic pond                                                                                         99 Figure 36       Different baffle arrangements with 70% pond width                         facultative pond                                                                                       100 Figure 37       Different baffle arrangements with 70% pond width                         maturation pond                                                                                     100 Figure 38     Data conversion for reactor length to width ratio to N for                       N-tanks in series model                                                                         102 Figure 39     Description of length to width ratio for the laboratory-scale                         model                                                                                                     102 Figure 310     Triangular meshes for the model anaerobic reactor                               111 Figure 311     Triangular meshes for the model facultative reactor                             111 Figure 312     Triangular meshes for the model maturation reactor                           112 Figure 313   Model Navigator showing the application modes                                 113 Figure 314   Correlation data of the predicted-CFD and observed effluent Faecal                         coliform counts in baffled pilot-scale ponds                                         115 Figure 315   General arrangements of conventional longitudinal baffles of                       different lengths in the anaerobic pond                                                 117 Figure 316   General arrangements of conventional longitudinal baffles of                       different lengths in the facultative pond                                                 117 Figure 317   General arrangements of conventional longitudinal baffles of                       different lengths in the maturation pond                                                 118 Figure 318     Mesh structure in a 4 baffled 70% Transverse Anaerobic reactor           118     Figure 319     Mesh structure in a 4 baffled 70% Longitudinal Anaerobic reactor         119 Figure 320     Mesh structure in a 4 baffled 70% Transverse Facultative                       119 Figure 321     Mesh structure in a 4 baffled 70% Longitudinal Facultative                           reactor                                                                                                       120 Figure 322     Mesh structure in a 4 baffled 70% Transverse Maturation                           reactor                                                                                                       120 Figure 323     Mesh structure in a 4 baffled 70% Longitudinal Maturation                           reactor                                                                                                       121 Figure 324     Workflow showing all links and nodes in the user application                           interface                                                                                                   127 Figure 325     Logic End properties dialogue interface                                                   128 Figure 326     Data variable carrying nodes and the input variable properties                           Dialogue interface                                                                                   129 Figure 327     Template for the calculator properties and JavaScript                           expression editor                                                                                     130 Figure 328     Output variable mining interface and input template editor                   131 Figure 329     DOS Batch properties and batch test editor for mined data                   132 Figure 330     Constraint properties dialogue in the workflow canvas                         135 Figure 331     Objective properties dialogue in the workflow canvas                           135 Figure 332     DOE properties dialog showing the initial population of designs           136 Figure 333     Scheduler properties dialog showing optimization wizards                   137 Figure 334     Designs table showing the outcomes of different reactor                         configurations                                                                                         144 Figure 335     History cost on designs table showing the optimized cost     &a