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Polyelectrolytes in the Treatment of Wastewaters Martins Olusola Ogedengbe Iowa State University

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Polyelectrolytes in the Treatment of Wastewaters Martins Olusola Ogedengbe Iowa State University Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1972 Polyelectrolytes in the treatment of wastewaters Martins Olusola Ogedengbe Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Civil and Environmental Engineering Commons Recommended Citation Ogedengbe, Martins Olusola, "Polyelectrolytes in the treatment of wastewaters " (1972). Retrospective Theses and Dissertations. 4765. https://lib.dr.iastate.edu/rtd/4765 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This dissertation was produced from a microfilm copy of the original document. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the original submitted. The following explanation of techniques is provided to help you understand markings or patterns which may appear on this reproduction. 1. The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting thru an image and duplicating adjacent pages to insure you complete continuity. 2. When an image on the film is obliterated with a large round black mark, it is an indication that the photographer suspected that the copy may have moved during exposure and thus cause a blurred image. You will find a good image of the page in the adjacent frame. 3. When a map, drawing or chart, etc., was part of the material being photographed the photographer followed a definite method in "sectioning" the material. It is customary to begin photoing at the upper left hand corner of a large sheet and to continue photoing from left to right in equal sections with a small overlap. If necessary, sectioning is continued again — beginning below the first row and continuing on until complete. 4. The majority of users indicate that the textual content is of greatest value, however, a somewhat higher quality reproduction could be made from "photographs" if essential to the understanding of the dissertation. Silver prints of "photographs" may be ordered at additional charge by writing the Order Department, giving the catalog number, title, author and specific pages you wish reproduced. University Microfilms 300 North Zeeb Road Ann Arbor. Michigan 46106 A Xerox Education Company 73-9472 OGEDENGBE, Martins Olusola, 1943- POLYELECTROLYTES IN THE TREATÎ-ENT OF WASTEWATERS. Iowa State University, Ph.D., 1972 Engineering, sanitary and municioal University Microfilms, A XEROX Company, Ann Arbor, Michigan TTJTC -nTCCTm' Polyelectrolytes in the treatment of wastewaters by Martins Olusola Ogedengbe A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Department: Civil Engineering Major: Sanitary Engineering Approved: Signature was redacted for privacy. In Charge of Major Work Signature was redacted for privacy. For the MajorxDepartment Signature was redacted for privacy. For the Graduate college Iowa State University Ames, Iowa 1972 PLEASE NOTE; Some pages may have indistinct print. Filled as received. University Micro-riims, A Xerox Ed ii TABLE OF CONTENTS Page I. INTRODUCTION 1 II. BACKGROUND ON FOLYELECTROLYTES 7 A. What are Polyelectrolytes? 7 B. Mode and Extent of Polyelectrolyte Utilization 11 1. Extent of utilization 12 C. Advantages and Disadvantages in Polyelectrolyte Usage 16 III. FUNDAMENTALS OF PARTICLE AGGREGATION 18 A. Colloid and Colloid Stability 18 1. Description of colloids 18 2. General properties of colloids 20 3. Nature of colloid stability 21 B. Criteria for Particle Settleability 27 1. Elsziezts of StCiCes ' equation 27 2. Instability factors in a colloidal dispersion 31 3. Summary of stability and instability forces 36 IV. THE COAGULATION PROCESS 39 A. General Background 39 B- Principles of Coagulation 40 1. The electrical double layer 40 2. The zeta potential 45 3. Measurement of charge 46 4. Charge neutralization 48 5. Bridging model 52 C- Summary of the Coagulation Process 60 D. Coagulation versus Flocculation 62 iii V. A REVIEW OF PERTINENT LITERATURE 65 A. General 65 B. Velocity Gradient 67 C. Rapid Mix 69 D. Slow Mix 73 VI. SPECIFIC OBJECTIVES OF STUDY 79 VII. EXPERIMENTAL INVESTIGATIONS 82 A. Background 82 B. Phase I 82 1. Materials and apparatus 82 2- Sampling and test procedures 87 3. Results and interpretations 93 4. A capsular summary of phase I results 114 C. Experimental Investigations—Phase II 119 1. Materials 119 2- Apparatus 120 3. Sampling procedure 125 4. Test procedures 126 5. Results and interpretations 128 6. Optimum polymer dosage and dosing technique 142 7. The dimensionless quantity Gt 154 8. Economics 155 VIII. SUMMARY AND CONCLUSIONS 161 IX. RECOMMENDATIONS 164 X. LITERATURE CITED 165 XI. ACKNOWLEDGMENTS 171 iv LIST OF FIGURES Page Figure 1. Flow diagram through a wastewater treat­ ment plant 2 Figure 2. Recurring molecular units of natural and synthetic polymers, (a) shows the structural formula of starch, a natural polymer; and (b) shows that of a synthetic polymer— polyacrylic acid 9 Figure 3. Examples of nonionic, anionic and cationic polyelectrolytes, (b) is a partly hydrolyzed polyacrylamide and (c) is a partly substi­ tuted quartenary ammonium group 10 Figure 4. Elements of stoke ' s eqpiation 29 Figure 5. A schematic representation of ion and potential distribution in the double layer according to the theories (a) Helmholtz (30), (b) Gouy (26) Chapnan (16), and (c) Stern (55). denotes the total potential, the zeta potential 42 Figure 6. The interaction energy picture. The re- by algebraic addition of the repulsive energy curve B. H is the energy barrier that must be overcome to achieve particle destabilization in a hydrophobic colloidal system 49 Figure 7 Electron micrographs of colloidal silica and a cationic polymeric flocculant. A- silica blank; B-silica plus flocculant; C-silica plus flocculant (shadowcase); D-silica plus flocculant at higher mag­ nification (shadowcast). Electron micro­ graph of polystyrene latex and a cationic polymeric flocculant. Markers in all fig­ ures indicate 1 micron (49) 57 Figure 8, Reactions which can occur with colloidal parricles and polymers, as suggested by O'melia (43) 59 V Figure 9, Effect of time of rapid mix on particle- size equilibrium/ from Tekippe and Ham (60) 72 Figure 10, A hypothetical set of curves showing the polyelectrolyte dosages needed (ideally) to reach optimum turbidity removal with the split-flow-dosing technique and the nonsplit 81 Figure 11, An arrangement for determining electro- phoretic mobility. A indicates the di­ rect current source and indicator, B is the source of illuminating light for the cell under the microscope C, and D is the entrance for the sample under study. The exit is hidden behind the microscope in the picture 86b Figure 12. Sewage flow variation ai Ames' treatment plant 88 Figure 13. Multiple stirrer commonly used in jar- tests in coagulation studies (courtesy of Phipps and Bird) 90 Figure 14. Plots of residual turbidity versus dosage of the polyelectrolyte, Nalco 610, for all five dosing teclmiques. Run No. 1-07-72/ Ames raw sewage 98 Figure 15. Plots of residual turbidity versus dosage of the polyelectrolyte, Nalco 610, for all five dosing techniques. Run No. 1-10-72, Ames' raw sewage 99 Figure 16. Plots of residual turbidity versus dosage of the polyelectrolyte, Nalco 610, for all five dosing techniques. Run No. 1-17-72/ Ames' raw sewage 100 Figure 17. Average rank for dosage and dosing- technique combinations. Lower ranks represent better performance 103 1? " -v" 4-5 TO Plots of residual suspended solids and turbidity versus dosage of the polyelectro­ lyte, Nalco 610, for nonsplit, and 50:50 Run No. 2-01-72 /mes' raw sewage 106 vi Figure 19. Plots of residual suspended solids and turbidity versus dosages of the poly- electrolyte Nalco 610, for nonsplit and 50:50 split. Run no, 2-05-72, Ames* raw sewage 107 Figure 20. Plots of residual suspended solids and turbidity versus dosage of the poly- electrolyte, Nalco 610, for nonsplit and 50:50 split. Run No. 2-02-72, Boone's raw sewage 109 Figure 21. Plots of suspended solids and turbidity removals versus dosage of the poly- electrolyte Nalco 610, for nonsplit and 50:50 split. Run no. 2-11-72, Ames' primary effluent 111 Figure 22. Plots of turbidity and suspended solids removals versus dosage of Nalco 610 for varying times of rapid mix. Run No. 2-17-72, Ames' raw sewage 116 Figure 23. Percent removals versus dosage of Nalco 610 for 4 minutes rapid mix. Run No. 2-18-72, Ames' raw sewage 118 Figure 24. A plot of N (rpm) versus torque (milli­ volts) for varying velocity gradients 123 Figure 25. A calibration curve for the Master Servodyne determining N, and T cor­ responding to different velocity gradients 124 Figure 26. Effects of velocity gradient and time of rapid mix on turbidity removal. Ames primary effluent coagulated with 10 mg/1 Nalco 610. Run No. 7-20-72 132 Figure 27. Plots of residual turbidity versus time of rapid mix for Nalco 610 varying G- values. Ames' primary effluent with 10 mg/1. Run No. 7-21-72 133 Figure 23. Plots of residual turbidity versus time of rapid mix for varying G-values, Ames' primary effluent with 10 mg/1 Nalco 610. Run No. 7-26-7 2 134 vii Figure 29. Effects of increasing clay dosage on clarification of Ames' primary effluent coagulated with 10 mg/1 Nalco 610.
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