Standard Methods, method 2540 D. Membrane filter papers (GF 52 Glass .....
PRAESTOL 2540 is used mainly for flocculation of mineral and hydroxide type.
UTILIZATION OF NATURAL POLYELECTROLYTES IN WASTEWATER TREATMENT
by Berna HASÇAKIR
July, 2003 İZMİR
UTILIZATION OF NATURAL POLYELECTROLYTES IN WASTEWATER TREATMENT
A Thesis Submitted to the Graduate School of Natural and Applied Sciences of Dokuz Eylül University In Partial Fulfillment of the Requirements for the Degree of Master of Science in Environmental Engineering, environmental Technology Program
by Berna HASÇAKIR
July, 2003 İZMİR
M.Sc THESIS EXAMINATION RESULT FORM We certify that we have read this thesis and “Utilization of Natural Polyelectrolytes in Wastewater Treatment” completed by Berna HASÇAKIR under supervision of Assist. Prof. Dr. Deniz DÖLGEN and that in our opinion it is fully adequate, in scope and in quality, as a thesis for the degree of Master of Science.
Assist. Prof. Dr. Deniz DÖLGEN Supervisor
(Committee Member)
(Committee Member)
Approved by the Graduate School of Natural and Applied Sciences
Prof.Dr. Cahit HELVACI Director
II
ACKNOWLEDGMENTS
I would first like to express my appreciation to my thesis supervisor, Assist. Prof. Dr. Deniz DÖLGEN who has supported me scientifically and morally throughout my study. She has shared all her knowledge and experience with me and spent her time when I need. Therefore, I am very grateful to her. I would like to express my grateful to all of my friends, especially to Mehmet ÖZBEK, Zeynep AKYOL, Meltem AKKUŞ and Serpil GÜLEL and laboratory staff for their patience and help during the course of this study. Finally, I would like to thank to my family for their endless moral and encouragement.
Environmental Engineer Berna HASÇAKIR
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ABSTRACT
Chemical treatment processes such as coagulation/flocculation/sedimentation, chemical oxidation/reduction, adsorption, etc. have been used effectively over the years for both water and wastewater treatment purposes. Pollutants which are not easily removed by conventional biologic treatment systems such as colloidal matters, refractory organics, nutrient mainly phosphorus, heavy metals, inorganic matters can be eliminated by chemical treatment methods. Among the various techniques, coagulation/flocculation/sedimentation (CFS) deserves special importance. CFS process is affected from the chemicals used in the process. Therefore, researches on chemicals (coagulant/flocculant) have been continued concerning the type, performance, doses, etc. The aim of this study is to investigate the possible uses of two additives, i.e. starch and kaolin. Experimental studies have been performed by wastewater taken from corrugated box manufacturing factory that are located in Kemalpasa region. The performances of two materials have been examined for CFS, Air Flotation and Sedimentation alternatives. In CFS process, starch and kaolin has been used as coagulant and flocculant. Throughout the experiments effectiveness of typical chemicals, i.e. alum, lime, ferric chloride and polyelectrolyte have been assessed to compare the common ones with starch and kaolin. The optimum doses of all materials have been determined via jar testing. The effect of starch and kaolin to flotation process has also investigated in this study by simple flotation equipment. COD (Chemical Oxygen Demand) measurements have been used for the decision of the optimum dose. In addition, the effect of sedimentation on treatment performance has been investigated. Finally, combination of sedimentation and CFS process has been studied in the thesis. Following to primary sedimentation, wastewater samples
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have been subjected to CFS process. And, the treatment performance of each stage was determined separately. As a result, approximately 85-90% COD removal efficiency has been achieved by starch as coagulant for industrial wastewater while only 20% has obtained for domestic fraction. When the kaolin is introduced as coagulants, treatment performance has been increased to 45% for domestic wastewater. For the wastewater originated from corrugating and printing processes, 65-70% of organic material has been eliminated. In addition, for the wastewater generated from only printing process including high organic content, solid particles and color, kaolin has been shown excellent performance, i.e. >95%. Utilization of starch as flocculant together with typical coagulants such as alum, lime and FeCl3, have not improved the efficiency. For domestic wastewater app. 30-35% of organic matter has been removed by starch whereas 70-75% efficiency has been obtained for industrial wastewater originated from corrugating and printing processes. However, when the kaolin is used as flocculant, higher removal efficiencies have been achieved for domestic wastewater. Maximum COD efficiency which is around 80% has obtained for FeCl3+Kaolin alternatives. Similar results regarding to wastewater produced from printing process have been achieved when starch and kaolin is used as flocculant. For the alternatives of alum plus starch or alum plus kaolin, superior treatment performance (>90%) has been accomplished. In addition, when starch and kaolin is used as flocculant together with FeCl3, 95% removal of COD has been achieved. Therefore, experimental results conducted for starch and kaolin encourage the use of these materials for wastewater treatment purpose. Starch and kaolin offers certain advantages such as availability (easy to obtain), cost, neutral pH conditions, etc. thus makes their uses reasonable.
V
ÖZET
Koagülasyon/flokülasyon/çökeltim,
kimyasal
oksidasyon
redüksiyon,
adsorpsiyon vb. kimyasal arıtma süreçleri senelerdir gerek su gerekse de atıksu arıtımı amacıyla verimli olarak kullanılmaktadır. Konvansiyonel biyolojik arıtma sistemleri ile kolaylıkla giderilemeyen kolloidal maddeler, kalıcı organikler, fosfor gibi nütrientler, ağır metal, inorganik maddeler kimyasal yöntemler ile giderilebilir. Pek çok teknoloji arasında koagülasyon / flokülasyon / çökeltim (KFÇ) özel önem arz etmektedir. KFÇ süreçleri kullanılan kimyasallardan etkilenmektedir. Bu nedenle, kimyasalların (koagülant / flokülant) türü, verimi, dozlarına ilişkin yapılan araştırmalar sürdürülmektedir. Bu çalışmanın amacı, nişasta ve kaolinin kullanılabilirliğinin araştırılmasıdır. Deneysel çalışmalar Kemalpaşa bölgesinde kurulu oluklu mukavva üretimi yapan iki ayrı fabrikadan temin edilen atıksular ile gerçekleştirilmiştir. Her iki malzemenin verimi KFÇ, hava flotasyonu ve çökeltim seçenekleriyle belirlenmiştir. KFÇ sürecinde nişasta ve kaolin koagülant ve flokülant olarak kullanılmıştır. Deneyler süresince alum, kireç, demir klorür ve polielektrolit gibi tipik kimyasalların verimi de nişasta ve kaolin ile karşılaştırmak amacıyla değerlendirilmiştir. Her malzemeye ait optimum doz jar testi ile belirlenmiştir. Bu çalışmada nişasta ve kaolinin flotasyon prosesine etkisi basit flotasyon ekipmanı kullanılarak incelenmiştir. Optimum dozu belirlemede KOİ ölçümleri kullanılmıştır. Bunlara ek olarak, çökeltimin arıtma verimine etkisi incelenmiştir. Son olarak, KFÇ ve çökeltim süreçleri beraberce kullanılmıştır. Ön çökeltim işleminin ardından atıksu örnekleri KFÇ sürecine tabi tutulmuştur. Arıtma verimi her kademe için ayrı ayrı ortaya konmuştur. Sonuç olarak, nişastanın koagülant olarak kullanıldığı koşullarda endüstriyel atıksu ile yapılan deneylerde yaklaşık 85-90% KOİ giderimi elde edilirken, evsel atıksular için %20 civarında giderim sağlanmıştır. Kaolinin koagülant olarak
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kullanılması halinde arıtma verimi evsel atıksu için %45’e yükselmiştir. Mukavva üretimi ve mürekkep ile baskı yapılması süreçlerinden kaynaklanan atıksular için ise 65-70% oranında organik madde giderimi sağlanmıştır. Ayrıca, yüksek organik madde, katı madde içeren ve koyu renkli olan sadece mürekkep ile baskı yapılan işlemlerden kaynaklanan atıksuların kaolin ile işlem görmesi sonucunda %95 ve daha yukarısı verimler elde edilebilmiştir. Nişastanın alum, kireç ve demir klorür gibi standart koagülantlar ile birlikte flokülant olarak kullanılması halinde verimde artış sağlanmamıştır. Evsel atıksu ile yapılan deneylerde nişastanın flokülant olarak kullanılması durumunda %30-35 verim elde edilmesine karşın endüstriyel nitelikli atıksu için % 70-75’e ulaşılmıştır. Ancak, kaolin flokülant olarak kullanıldığında evsel atıksu için yüksek giderim verimleri gerçekleşmiştir. En yüksek KOİ verimi demir klorür ve kaolinin beraber kullanıldığı koşullarda gerçekleşmiş olup %80 oranında verim elde edilmiştir. Mürekkep ile baskı yapılan işlemlerden kaynaklanan atıksular için nişasta ve kaolin flokülant olarak kullanıldığında da benzer sonuçlara ulaşılmıştır. Alum ve nişasta veya alum ve kaolin ile yapılan deneylerde de çok iyi sonuçlar elde edilmiştir (>90%). Buna ek olarak, nişasta ve kaolinin demir klorür ile birlikte flokülant olarak kullanıldığı koşullarda % 95 KOİ giderimi sağlanmıştır. Sonuç olarak, nişasta ve kaoline dair elde edilen sonuçlar bu malzemelerin atıksu arıtımı amacıyla kullanımını desteklemektedir. Nişasta ve kaolin kolay temin etme, ekonomiklik, nötral pH koşulları vb. avantajlar sunması bakımından uygulamaları mümkün kılmaktadır.
VII
CONTENTS
Pages Acknowledgements ………………………………………………………………….II Abstract ……………………………………………………………………………..III Özet ……………………………………………………………………………….....V Contents ……………………………………………………………………………VII List of Tables.………………………………………………………………………XII List of Figure ……………………………………………………………………..XIV
Chapter One INTRODUCTION 1. 1.Introduction …….……………………………………………………………1
Chapter Two CHEMICAL TREATMENT 2.1.General ……………………………………………………………………...4 2.2. Chemical Coagulation and Flocculation …………………………………...6 2.2.1. Colloidal Systems ………………………………………………...........6 2.2.1.1. The Stability of Colloids ……………………………..………………7 2.2.1.2. Destabilization of Colloids ………………………………..………..10 2.2.2. Coagulation ………………………………………………………......14 2.2.2.1.Mechanism of Coagulation ………………………………………….14 2.2.2.1.1. Factors of Effecting Coagulation ………………………………15 2.2.2.2. Coagulants ………………………………………………………….18 2.2.2.3. Design Parameters for Coagulation Process ……………………......21
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2.2.3. Flocculation ………………………………………………………......22 2.2.3.1.Mechanism of Flocculation ………………………………………....22 2.2.3.2. Flocculants ……………………………………………………….....24 2.2.3.3.Design Parameters for Flocculation Process ………………………..25 2.2.4. Sedimentation ………………………………………………………...26 2.2.4.1.Mechanism of Sedimentation ……………………………………….26 2.2.4.2.Design Parameters for Sedimentation Process ……………………...27
Chapter Three EXPERIMENTAL STUDIES 3.1. Experimental Setup …………………………………………….................28 3.1.1. Jar Test Apparatus ……………………………………………………28 3.1.2. Air Flotation Apparatus……………………………………………....30 3.1.3. Imhoff Cone………………………………………………………......30 3.2. Experimental Procedure………………………………………………......31 3.3. Experimental Analysis……………………………………………………33 3.4. Wastewater Characterization…………………………………………......34 3.5. Chemicals Used In the Experimental studies…………………………......36 3.5.1. Starch…………………………………………………………………36 3.5.1.1. General Properties of Starch……………………………………...36 3.5.1.2. Types of Starch…………………………………………………...37 3.5.1.3. Starch Products…………………………………………………...38 3.5.2. Kaolin……………………………………………………....................40 3.5.2.1. Geology of Kaolin………………………………………………...40 3.5.2.2. Characterization of Kaolin…………………………………..........41 3.5.2.3. Uses of Kaolin ….…………………………………………….......41 3.5.3. Alum……………………………………………………………….....42 3.5.4. Ferric Chloride………………………………………………………..43 3.5.5. Lime…………………………………………………………………..43 3.5.5.1. Geological Description of Limestone………………………….....43
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3.5.5.2. Physical Characteristics of Limestone………………………........44 3.5.6. Polyelectrolytes ………………………………………………………46 3.5.6.1. Polyelectrolyte 1………………………………………………….46 3.5.6.2. Polyelectrolyte 2………………………………………………….46
Chapter Four EXPERIMENTAL RESULTS 4.1. Coagulation / Flocculation / Sedimentation (CFS) Process…………………..48 4.1.1. Use of Various Chemicals as Coagulant in CFS Process………………...48 4.1.1.1. Starch…………………………………………………………………48 4.1.1.1.1. Finding the Optimum pH Range of Starch……………………….51 4.1.1.2. Kaolin …………………………………………………………….......52 4.1.1.2.1. Finding the Optimum pH Range of Kaolin ………………………55 4.1.1.3. Alum …………………………………………………………………56 4.1.1.4. Ferric Chloride (FeCl3) ………………………………………………59 4.1.1.5. Lime ………………………………………………………………….60 4.1.2. Use of Starch and Kaolin as Flocculants in CFS Process ………………..62 4.2. Flotation………………………………………………………………………76 4.2.1. Flotation Without Any Chemicals………………………………………..76 4.2.2. Flotation With Chemicals…………………………………………...........77 4.3. Sedimentation………………………………………………………………...81 4.3.1. Plain Sedimentation (PS) ………………………………………...............81 4.3.2. Chemical Precipitation……………………………………….…...............82 4.4. Combined Treatment Alternative (PS+CFS) ………………………………...83
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Chapter Five EVALUTION OF RESULTS 5.1. Treatment Performance of Various Chemicals as Coagulant………………...89 5.1.1. Treatment Performance of Starch as Coagulant………………………….89 5.1.2. Treatment Performance of Kaolin as Coagulant…………………………93 5.1.3. Treatment Performance of Alum as Coagulant………………………….96 5.1.4. Treatment Performance of FeCl3 as Coagulant………………………...100 5.1.5. Treatment Performance of Lime as Coagulant………………………….104 5.2. Treatment Performance of Various Flocculants……………………………108 5.2.1. Treatment Performance of Starch………………………………………109 5.2.2. Treatment Performance of Kaolin………………………………………114 5.2.3. Treatment Performance of Polyelectrolytes…………………………….120 5.2.3.1. Polyelectrolyte 1…………………………………………………….121 5.2.3.2. Polyelectrolyte 2…………………………………………………….127 5.3. Treatment Performance of Flotation with and without Chemicals………….132 5.3.1. Treatment Performance of Flotation without any Chemicals…………...133 5.3.2. Treatment Performance of Flotation with Chemicals…………………...134 5.4. Treatment Performance of Plain Sedimentation with and without Chemicals……………………………………………………………………138 5.4.1. Treatment Performance of Sedimentation without any Chemicals……..139 5.4.2. Treatment Performance of Chemicals Precipitation…………………….140 5.5. Treatment Performance of Plain Sedimentation + Coagulation / Flocculation / Sedimentation………………………………………………………………..141
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Chapter Six CONCLUSIONS 6.1. Conclusions …………………………………………………………………146
References ……………………………………………………………………….151 Appendix ………………………………………………………………………...153
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LIST OF TABLES
Pages Table 2.1 Design parameters for rapid mixing unit ...……………………………...21 Table 2.2 Design parameters of flocculation tank………………………………….26 Table 2.3 Design parameters of sedimentation tanks…….………………………...27 Table 3.1 Characterization of wastewater used in the experimental studies …........35 Table 3.2 The properties of kaolin used in experiments ……………………………41 Table 4.1 Utilization of starch as coagulant in CFS process for WW1 ……………49 Table 4.2(a-b): Utilization of starch as coagulant in CFS process for WW2…...49-50 Table 4.3 Utilization of starch as coagulant in CFS process for WW3 ……............50 Table 4.4 Utilization of starch as coagulant in CFS process for WW4 ……………51 Table 4.5 Investigation of optimum pH range for starch ……………………...........52 Table 4.6 Utilization of kaolin as coagulant in CFS process for WW1 ……………53 Table 4.7(a-b) Utilization of kaolin as coagulant in CFS process for WW2 …...53-54 Table 4.8(a-b) Utilization of kaolin as coagulant in CFS process for WW3……54-55 Table 4.9 Utilization of kaolin as coagulant in CFS process for WW4 ……………55 Table 4.10 Investigation of optimum pH range for kaolin ..………………………..56 Table 4.11 Utilization of alum as coagulant in CFS process for WW1 ……………57 Table 4.12(a-b) Utilization of alum as coagulant in CFS process for WW2 ……57-58 Table 4.13 Utilization of alum as coagulant in CFS process for WW3 …………….58 Table 4.14 Utilization of alum as coagulant in CFS process for WW4 ……….........58 Table 4.15 Utilization of FeCl3 as coagulant in CFS process for WW1 ………........59 Table 4.16 Utilization of FeCl3 as coagulant in CFS process for WW2 ……………59 Table 4.17 Utilization of FeCl3 as coagulant in CFS process for WW3 ……………60 Table 4.18 Utilization of FeCl3 as coagulant in CFS process for WW4 ……………60
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Table 4.19 Utilization of lime as coagulant in CFS process for WW1 ……………..61 Table 4.20 Utilization of lime as coagulant in CFS process for WW2 ………..........61 Table 4.21 Utilization of lime as coagulant in CFS process for WW3 …….……….62 Table 4.22 Utilization of lime as coagulant in CFS process for WW4 ……………..62 Table 4.23 The results of CFS experiments for WW1 (coagulant: alum ) …………64 Table 4.24 The results of CFS experiments for WW1 (coagulant: FeCl3) …………65 Table 4.25 The results of CFS experiments for WW1 (coagulant: lime) ………......66 Table 4.26 The results of CFS experiments for WW2 (coagulant: alum) ………….67 Table 4.27 The results of CFS experiments for WW2 (coagulant: FeCl3) …………68 Table 4.28 The results of CFS experiments for WW2 (coagulant: lime) …………..69 Table 4.29 The results of CFS experiments for WW3 (coagulant: alum) ………….70 Table 4.30 The results of CFS experiments for WW3 (coagulant: FeCl3) …………71 Table 4.31 The results of CFS experiments for WW3 (coagulant: lime) …………..72 Table 4.32 The results of CFS experiments for WW4 (coagulant, alum) ……….....73 Table 4.33 The results of CFS experiments for WW4 (coagulant: FeCl3) …………74 Table 4.34 The results of CFS experiments for WW4 (coagulant: lime) …………..75 Table 4.35 The results of plain flotation for each wastewater ……………………...76 Table 4.36 Experimental results of flotation process for starch ……………............77 Table 4.37 Experimental results of flotation process for kaolin…………………….78 Table 4.38 Experimental results of flotation process for alum .…………………….79 Table 4.39 Experimental results of flotation process for FeCl3 …………………….80 Table 4.40 Experimental results of flotation process for lime ……………………...81 Table 4.41 Experimental results of primary sedimentation unit of each wastewater………………………………………………………………82 Table 4.42 The results of the Chemical precipitation studies with HCl addition …………………………………………………………………83 Table 4.43 The results of treatability studies (coagulant: starch) ………………......84 Table 4.44 The results of treatability studies (coagulant, kaolin) .………………….85 Table 4.45 The results of treatability studies (coagulant, alum) ….………………...86 Table 4.46 The results of treatability studies (coagulant, FeCl3) ….………………..87 Table 4.47 The results of treatability studies (coagulant, lime) …….…………........88
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LIST OF FIGURES Pages Figure 2.1 The dimensions of the colloids in water bodies ………………………… 7 Figure 2.2 Charge system in a colloidal suspension………………………………….8 Figure 2.3 Ionic Compression: reduction of thickness in diffused layer…….……….9 Figure 2.4 Ionic Compression: reduction of net force…...……………………….....10 Figure 2.5 Interparticle bridging with polymers.……..……. ……………………....13 Figure 3.1 (a)Schematic representation of Jar test apparatus, (b) photograph of Jar test apparatus ………….…………………………………………..29 Figure 3.2. Aeration apparatus…….………………………………………………..30 Figure 3.3. Imhoff cone…………………………………………………………….31 Figure 5.1. COD removal efficiency of starch for WW1…..………………………90 Figure 5.2. COD removal efficiency of starch for WW2………………………......90 Figure 5.3. COD removal efficiency of starch for WW3…..………………………91 Figure 5.4. COD removal efficiency of starch for WW4…..……………………....91 Figure 5.5. Summary of the experimental data for optimum starch doses conducted for each parameter……..……………………………..92 Figure 5.6. COD removal efficiency of kaolin for WW1 …...………………….….93 Figure 5.7. COD removal efficiency of kaolin for WW2…...…….………………. 94 Figure 5.8. COD removal efficiency of kaolin for WW3…...………………...……94 Figure 5.9. COD removal efficiency of kaolin for WW4 ...……………………...…95 Figure 5.10. Summary of the experimental data for optimum kaolin dose conducted for each parameter……...………………………...…..96 Figure 5.11. COD removal efficiency of alum for WW1…………...……..………..97 Figure 5.12. COD removal efficiency of alum for WW2……………….……….….97 Figure 5.13. COD removal efficiency of alum for WW3………………………...…98 Figure 5.14. COD removal efficiency of alum for WW4………...…………………99 Figure 5.15. Summary of the experimental data for optimum alum dose conducted for each parameter …………………………........................99
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Figure5.16 COD removal efficiency of FeCl3 for WW1…………………………..101 Figure 5.17. COD removal efficiency of FeCl3 for WW2…………………………101 Figure 5.18. COD removal efficiency of FeCl3 for WW3…………………………102 Figure 5.19. COD removal efficiency of FeCl3 for WW4…………………………103 Figure 5.20. Summary of the experimental data for optimum FeCl3 dose conducted for each parameter. ……………………….........................104 Figure 5.21. COD removal efficiency of lime for WW1……………….………….105 Figure 5.22. COD removal efficiency of lime for WW2……………….………….106 Figure 5.23. COD removal efficiency of lime for WW3……….………………….106 Figure 5.24. COD removal efficiency of Lime for WW4…….…………………....107 Figure 5.25. Summary of the experimental data for optimum lime doses conducted for each parameter………..……………………...…108 Figure 5.26. COD removal efficiency of starch as flocculant (coagulant: alum)………………………………………………….…..109 Figure 5.27. Treatment performance of starch as flocculant in terms of solid matters, turbidity and color (coagulant: alum) ….........................110 Figure 5.28. COD removal efficiency of starch as flocculant (coagulant:FeCl3)……………………………………………………...111 Figure 5.29. Treatment performance of starch as flocculant in terms of solid matters, turbidity and color (coagulant: FeCl3 )…........................112 Figure 5.30. COD removal efficiency of starch as flocculant (coagulant: lime)…..…………………………...……………..……... 113 Figure 5.31. Treatment performance of starch as flocculant in terms of solid matters, turbidity and color (coagulant: lime)……………...…..114 Figure 5.32. COD removal efficiency of kaolin as flocculant (coagulant: alum)………………………………….…………………115 Figure 5.33. Treatment performance of kaolin as flocculant in terms of solid matters, turbidity and color (coagulant: alum)……………........116 Figure 5.34. COD removal efficiency of kaolin as flocculant for each wastewater (coagulant: FeCl3)………….…………………………………………117 Figure 5.35. Treatment performance of kaolin as flocculant in terms of solid matters, turbidity and color (coagulant: FeCl3)……..………….118
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Figure 5.36. COD removal efficiency of kaolin as flocculant (coagulant: lime)……………………………………………………...119 Figure 5.37. Treatment performance of kaolin as flocculant in terms of solid matters, turbidity and color (coagulant: Lime)…………...……120 Figure 5.38. COD removal efficiency of polyelectrolyte 1 as flocculant (coagulant: alum)……………………………………………..............121 Figure 5.39. Treatment performance of polyelectrolyte 1 as flocculant in terms of solid matters, turbidity and color (coagulant: alum)…………………122 Figure 5.40. COD removal efficiency of polyelectrolyte 1 as flocculant (coagulant: FeCl3)…………………………………………….............123 Figure 5.41. Treatment performance of polyelectrolyte 1 as flocculant in terms of solid matters, turbidity and color (coagulant: FeCl3) ………………..124 Figure 5.42. COD removal efficiency of polyelectrolyte 1 as flocculant (coagulant: lime)……………………………………………….…….125 Figure 5.43. Treatment performance of polyelectrolyte 1 as plocculant in terms of solid matters, turbidity and color (coagulant: lime)………...…….….126 Figure 5.44. COD removal efficiency of polyelectrolyte 2 as flocculant (coagulant: alum)……………... ……………………………………..127 Figure 5.45. Treatment performance of polyelectrolyte 2 as flocculant in terms of solid matters, turbidity and color (coagulant: alum)…………………128 Figure 5.46. COD removal efficiency of polyelectrolyte 2 as flocculant (coagulant: FeCl3)………………………………………..………….. 129 Figure 5.47. Treatment performance of polyelectrolyte 2 as flocculant in terms of solid matters, turbidity and color (coagulant: FeCl3).………130 Figure 5.48. . COD removal efficiency of polyelectrolyte 2 as flocculant (coagulant: lime)…………..………………………………………...131 Figure 5.49. Treatment performance of polyelectrolyte 2 as flocculant in terms of solid matters, turbidity and color (coagulant: lime)……….. 132 Figure 5.50. Treatment performance of flotation without using any chemicals in terms of chemical oxygen demand, solid matters, turbidity, color and oil &grease for each wastewater…………………………..133
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Figure 5.51. Treatment performance of flotation process with starch in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater. ………………………………………………….134 Figure 5.52. Treatment performance of flotation process with kaolin in terms of chemical oxygen demand, solid Matters, turbidity, color for each wastewater……………………………………………...……135 Figure 5.53. Treatment performance of flotation process with alum in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater………………………………………………..….136 Figure 5.54. Treatment performance of flotation process with FeCl3 in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater. …………………………….……………….……137 Figure 5.55. Treatment performance of flotation process with lime in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater.…………………………………………………..138 Figure 5.56. Treatment performance of sedimentation process without any chemicals in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater…………………….….139 Figure 5.57. Treatment performance of sedimentation process with HCl in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater…………………………………………………..140 Figure 5.58. Treatment performance of PS+CFS process with starch in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater. ………………………………………………….141 Figure 5.59. Treatment performance of PS+CFS process with kaolin in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater…………………………………………………...142 Figure 5.60. Treatment performance of PS+CFS process with alum in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater…………………………………………………..143
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Figure 5.61. Treatment performance of PS+CFS process with FeCl3 in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater…………………………………………………...144 Figure 5.62. Treatment performance of PS+CFS process with lime in terms of chemical oxygen demand, solid matters, turbidity, color for each wastewater…………………………………………………...145 Figure 6.1. Overall optimum doses and COD removal efficiencies belonging to these doses …………………………………………………………….147 Figure 6.2. COD removal efficiencies results with optimum dose of alum and optimum dose of various flocculant ………………………………148 Figure 6.3. COD removal efficiencies results with optimum dose of FeCl3 and optimum dose of various flocculant ………………………………148 Figure 6.4. COD removal efficiencies results with optimum dose of lime and optimum dose of various flocculant ………………………………149
1
CHAPTER ONE
INTRODUCTION
Chemical treatment is one of the most common and well-known methods used for wastewater treatment in general, particularly for industrial wastewater. Among the chemical treatment methods chemical precipitation, coagulation / flocculation / sedimentation (CFS), and chemical oxidation are more familiar in environmental engineering practices while others have limited applications. Since, industrial wastewater is usually the one, which has low biological degradability, chemical treatment methods have been considered as main treatment alternative preferably. In addition, industrial wastewater may contain inorganic constituents such as metals, which may cause toxic effects on to the biologic process, thus makes the use of chemical treatment methods vital before the biological processes. And, difficulties in the adaptation of microorganisms may influence the treatment efficiency negatively as well. Because of these reasons, chemical treatment methods have been used in industries effectively as a main treatment plant or pre-treatment unit. The basic principal of chemical treatment is to eliminate the impurities, which is difficult to remove from the wastewater by conventional treatment methods. Chemicals are mostly used within these processes. Coagulation/flocculation/sedimentation process is most popular one; since it shows higher treatment performance in terms and organic matter removal, solid matter removal, and heavy metal removal as well. Besides, other advantages such as lower sensitivity to toxic loadings and higher amounts of organics, easy operation; lack of skilful person requirement for operation, etc. encourages the CFS process applications especially for industrial wastewaters. Since wastewater characterization may change from industry to industry, and even in the same industry variations are
2
observed, it is very difficult to offer recipe treatment plant schemes. Therefore, bench scale laboratory studies, i.e. treatability studies, should be carried out before the design and implementation of full-scale treatment plants. The performance of chemical treatment processes is affected from wastewater quality (characterization of wastewater), chemicals used for removal of impurities, and operating conditions as well. Investigations regarding to new materials, which are effective, economic, environmentally friendship have been achieved. The aim of this study is to investigate the treatment performance of two materials, i.e. starch and kaolin,
and
use
them
in
wastewater
treatment.
In
this
context,
Coagulation/Flocculation/Sedimentation, Air Flotation, and Chemical Precipitation alternatives are examined. Throughout the studies, starch and kaolin are experienced both industrial and domestic wastewaters in terms of various parameters such as organic matter, solid particles, color and oil and grease. The performance of the chemicals has also been compared with typical ones, like alum, lime, ferric chloride and polyelectrolyte. During the experimental studies, the wastewater has been provided from two different corrugated box manufacturing factory. In the study, corrugating box manufacturing industry is chosen particularly. According to the latest modifications on Turkish Water Quality Control Regulation, the effluent limits are strengthened, hence each factory have to comply with the new standards. Although they have own treatment plants (chemical + biological), they have to upgrade their treatment plants in next days. Therefore, the results conducted from laboratory studies may be used as practically in the examined industries. Throughout the laboratory studies, treatability studies are performed with starch and kaolin. CFS process is experienced as first, and starch and kaolin are used as coagulant and flocculant separately. The effectiveness of chemicals has been investigated by COD parameter, and optimum dose of each material has been determined by COD removals. In addition to COD measurements, suspended solids, color, oil and grease, pH analyses have also been achieved.
3
Starch and kaolin are used as chemical in air flotation unit in the second step. During the experiments starch and kaolin have been introduced to flotation unit with increasing doses and the effectiveness of the chemicals have been investigated by COD parameter. The performances of the starch and kaolin have also been compared with other coagulants/flocculants such as alum, lime, ferric chloride and polyelectrolyte. Here, the performance of plane flotation has also been assessed in order to compare the results with chemical added flotation. Finally, within the framework of treatability studies, combination of CFS process with plain or primary sedimentation has been investigated as last alternative. Wastewater samples have subjected to CFS unit, i.e. jar test apparatus, after that primary sedimentation. Optimum dose of each chemicals, which are obtained from previous studies have been used in CFS stage. The performance of each unit has been determined separately, the efficiencies are determined from influent and effluent COD values. As a result of the experimental studies, effectiveness of starch and kaolin in various processes are investigated and compared with common chemicals in terms of costs, availability, environmental features as well as treatment performance.
4
CHAPTER TWO
CHEMICAL TREATMENT
2.1. General Chemical unit processes used for the treatment of wastewater in which change is brought about by means of or through chemical reaction. The most widely used chemical unit processes names are given below. (Metcalf & Eddy, 1991, p. 301) For water and wastewater treatment, many chemical treatment methods are applied. The names of common chemical treatment methods and their brief explanations are given below. • Adsorption: Adsorption is the process of collecting soluble substances that are in solution on a suitable interface (Metcalf & Eddy, 1991, p. 315). This process can be used for removal of organics not removed by conventional chemical and biological methods, also used for dechlorination of wastewater before final discharge for treated effluent. In water treatment this process is used as a polishing step and used for removing of dissolved organic matter. • Chemical precipitation: Chemical precipitation is the process whereby soluble phase species are removed from solution by adding a precipitant, which results in the formation of an insoluble compound containing the contaminant (N. Haas, J. Vamos, 1995, p. 132). The precipitate can then be separated from the wastewater using some physical separation process, such as sedimentation or filtration. This method is commonly used for removing of dissolved heavy metals or other dissolved hazardous inorganic contaminants, phosphorus and enhancement of suspended solids removal in primary sedimentation facilities used for physicalchemical treatment.
5
• Coagulation, flocculation, sedimentation: Coagulation and flocculation are the mechanisms by which particulate and colloidal materials are removed from water in the process of clarification. (N. Haas, J. Vamos, 1995, p. 144) • Disinfection: Disinfection refers to the selective destruction of diseasecausing organisms. Not all the organisms are destroyed during the process (Metcalf & Eddy, 1991, p. 324). This differentiates disinfection from sterilization, which is the destruction of all organisms. In disinfection process, many chemicals or methods can be used. The common chemicals that are used in disinfection process are chlorine, chlorine dioxide, bromine chloride and ozone. Ultraviolet light (UV) is the other method that is used for disinfection. •
Electrodialysis: In this process, ionic components of a solution are
separated through the use of semipermeable ion-selective membranes. This process are widely used for removing of dissolved solids. (Metcalf & Eddy, 1991, p. 759) • Ion exchange: It is a unit process in which ions of a given species are displaced from an insoluble exchange material by ions of a different species in solution (Metcalf & Eddy, 1991, p.740). It may be operated in either a batch or continuous mode. In a batch process, the resin is stirred with the water to be treated in a reactor until the reaction is complete. The spent resin is removed by settling and subsequently is regenerated and reused. In a continuous process, the exchange material is placed in abed or a packed column and the water to be treated is passing through it. Ion exchanger is used to remove dissolved ionic contaminants. • Neutralization: Neutralization is a treatment process designed to change the pH from a value outside the acceptable range to value that is within the acceptable range. Neutralization of acidic or basic wastewaters is minimized the corrosivity. (N. Haas, J. Vamos, 1995, p. 118)
6
• Oxidation: In advance wastewater treatment applications, chemical oxidation can be used to remove ammonia, to reduce the concentration of residual organics, and to reduce the bacterial and viral content of wastewater. (Metcalf & Eddy, 1991, p.751) The use of various chemicals to improve the results of other operations and processes. The practical application of these processes, including such matters as facility design and dosage requirements. Among all these chemical treatment methods, coagulation / flocculation / sedimentation is the most preferable one. The reasons of this preferable are given in detail, under the next topics.
2.2.Chemical Coagulation and Flocculation
2.2.1. Colloidal Systems We are accustomed to classify in three categories the water compounds: suspended solids, colloidal particles (less than 1 micron) and dissolved substances (less than several nanometers). There are different origins of these colloids: mineral substance dissolution, erosion, organic matter decomposition, farming wastes and wastewater. The colloid diameter is between 1 µm and 1nm. The rate surface/volume gives colloids very good adsorption properties for the free ions. This phenomenon of ion adsorption involves the presence of electronic charge at their surface, which brings about some repulsion forces. That is why colloids are so stable into solution.
7
Figure 2.1 The Dimentions of the Colloids in Water Bodies (Duran, N. Demirer, 1997, p. 44)
There are two general types of colloidal solid particle dispersions in liquids. When water is the solvent, these are called the hydrophobic, or “water-hating,” and the hydrophilic, or “water-loving,” colloids. These two types are based on the attraction of the particle surface for water. (Metcalf & Eddy, 1991, p.303) Hydrophobic particles have relatively little attraction for water; hydrophilic particles have a great attraction for water. It should be noted, however, that water can interact to some extent with hydrophobic particles. (S. Peavy et la., 1985, p. 131).Some water molecules will generally adsorb on the typical hydrophobic surface, but the reaction between water and hydrophilic colloids occurs to much greater extent. Basically the colloids are never 100 % hydrophilic nor 100 % hydrophobic, actually the percentage depends on their molecular constitution. (Metcalf & Eddy, 1991, p.304)
2.2.1.1. The Stability of Colloids Colloid suspensions that do not agglomerate naturally are called stable. The most important factor contributing to the stability of colloidal suspensions is the excessively large surface-to-volume ratio resulting from their very small size. (S. Peavy et la., 1985, p. 131). The other important factor in the stability of colloids is
8
the presence of surface charge. It develops in a number of different ways, depending on the chemical composition of the medium (wastewater in this case) and the colloid. Regardless of how it is developed, this stability must be overcome if these particles are to be aggregated (flocculated) into larger particles with enough mass to settle easily. (Metcalf & Eddy, 1991, p. 303) Ions contained in the water near the colloid will be affected by the charged surface. A negatively charged colloid with a possible configuration of ions around is shown in Figure 2.2. The first layer of cations attracted to the negatively charged surface is “bound” to the colloid and will travel with it, should displacement of the colloid relative to the water occur. Other ions in the vicinity of the colloid arrange themselves as shown, with greater concentration of positive, or counter, ions being closer to the colloidal surface. This arrangement produces a net charge that is strongest at the bound layer and decreases exponentially with distance from colloid.
Figure 2.2 Charge system in a colloidal suspension (S. Peavy et la., 1985, p. 132).
9
Figure 2.3 Ionic compression: reduction of thickness in diffused layer (S. Peavy et la., 1985, p. 132). When two colloids come in close proximity there are two forces acting on them. The electrostatic potential created by the “halo” of counter ions surrounding each colloid reacts to repel the particles, thus preventing contact. The second force an attraction force called the van der Waals force, supports contact. This force is inversely proportional to the sixth power of distance between the particles and also decays exponentially with distance. It decreases more rapidly than the electrostatic potential, but is a stronger force at close distance at close distance. The sum of the two forces as they relate to one colloid in close proximity to another is illustrated in Figure 2.3. As noted in the figure, the net force is repulsive at greater distances and becomes attractive only after passing through a maximum net repulsive force, called the energy barrier, at some distance between colloids. Once the force becomes attractive, contact between the particles takes place. S. Peavy et la., 1985, pp. 132-134
10
If a particle is placed in an electrolyte solution and an electric current is passed through the solution, the particle, depending on its surface charge, will be attracted to one or the other of the electrodes, dragging with it a cloud of ions. The potential at the surface of the cloud (called the surface of shear) is sometimes measured in wastewater treatment operations. The measured value is often called the zeta potential. (Metcalf & Eddy, 1991, p. 311) Theoretically, however, the zeta potential should correspond to the potential measured at the surface enclosing the fixed layer of ions attached to the particle. The use of the measured zeta potential value is limited because it will vary the nature of the solution components, and it therefore is not a repeatable measurement.
Figure 2.4 Ionic compression: reduction of net force
2.2.1.2. Destabilization of Colloids Different chemical coagulants can bring about the destabilization of colloids in different ways. Some materials can function as coagulants or as coagulant aids, and some coagulant can achieve colloidal destabilization by more than one method. The selection of the proper type and dosage of coagulant for a particular application
11
requires an understanding of how these materials function. Attention is directed here towards describing these mechanisms for destabilization. Four distinct methods are presented :
1. Compression of the diffuse layer (Ionic layer compression): The quantity of ions in the water surrounding a colloid has an effect on the decay function of the electrostatic potential. A high ionic concentration compresses the layers composed predominantly of counter ions toward the surface of the colloid. If this layer is sufficiently compressed, then the van der Waals force will be predominant across the entire area of influence, so that the net force will be attractive and no energy barriers will exist. An example of ionic layer compression occurs in nature when a turbid stream flows into the ocean. There the ion content of the water increases drastically and coagulation and settling occur. Eventually, deposits (deltas) are formed from material, which was originally so small that it could not have settled without coagulation. Although coagulants such as aluminum and ferric salts used in wastewater treatment ionize, at the concentration commonly used they would not increase the ionic concentration sufficiently to affect ion layer compression.
2. Adsorption to produce charge neutralization: The nature, rather than the quantity, of the ions is of prime importance in the theory of adsorption and charge neutralization. Although aluminum sulfate (alum) is used, as in the example below, ferric chloride behaves similarly. The ionization of aluminum sulfate in water produces sulfate anions (SO4-2) and aluminum cations (Al+3). The sulfate ions may remain in this form or combine with other cations. However, the Al+3 cations react immediately with water to form a variety of aquometallic ions and hydrogen.
12
Al3+ + H2O
AlOH2+ + H+
Al3+ + 2H2O
Al(OH2)+ + 2H+
7Al3+ + 17H2O
Al7(OH)174+ + 17H+
. . . Al3+ + 3H2O
Al(OH)3 + 3H+
The aquometallic ions thus formed become part of the ionic cloud surrounding the colloid and, because they have a great affinity for surfaces, are adsorbed onto the surface charge has been neutralize the surface charge. Once the surface charge has been neutralized, the ionic cloud dissipates and the electrostatic potential disappears so that contact occurs freely. Overdosing with coagulants can result in restabilizing the suspension. If enough aquometallic ions are formed and adsorbed, the charges on the particles become reversed and the ionic clouds reform, with negative ions being the counter ions.
3. Enmeshment in a precipitate (Sweep coagulation): According to equation below, the last product formed in the hydrolysis of alum and aluminum hydroxide, Al(OH)3. The Al(OH)3 forms in amorphous, gelatinous flocs that are heavier than water and settle by gravity. Colloids may become entrapped in a floc as it is formed, or they may become enmeshed by its “sticky” surface as the flocs settle. The process by which colloids are swept from suspension in this manner is known as sweep flocculation. Al3+ + 3H2O
Al(OH)3 + 3H+
4. Adsorption to permit interparticle bridging : Large molecules may be formed when aluminum or ferric salts dissociate in water. As an example 7Al3+ + 17H2O
Al7(OH)174+ + 17H+
this equation can be given, although larger ones are probably formed also. Synthetic polymers also may be used instead of, or in addition to metallic salts. These
13
polymers may be linear or branched and are highly surface reactive. Thus, several colloids may become attached to one polymer and several polymer-colloid groups may become enmeshed (Figure 2.5), resulting in a settleable mass.
In addition to adsorption forces, charges on the polymer may assist in the coagulation process. Metallic polymers formed by the addition of aluminum or ferric salts are positively charged, while synthetic polymers carry positive or negative charges or may be neutral. Judicious choice of appropriate charges may do much to enhance the effectiveness of coagulation. S. Peavy et la., 1985, pp. 134-136
Figure 2.5 Interparticle bridging with polymers. (Duran, N.Demirer,1997, p. 53)
14
The destabilization of colloids in water and wastewater treatment processes is probably accomplished either by adsorption of coagulant species or by enmeshment within hydroxide or carbonate precipitates (W. J. Weber, 1972). When destabilization is brought about by adsorption, the sorbable species are usually polymers. These polymers may be added directly to the process (e.g. Synthetic organic polymers, activated silica), they may be produced within the process from salts added to the system (e.g. Al (III) and Fe (III) salts), or they may be produced directly within the system from substances present in the water or wastewater (e.g. Extracellular polymers). In the case of lime, coagulation is accomplished by simple precipitation of CaCO3 and, at higher pH, Mg(OH)2. Aluminum and iron coagulations are more complex.
2.2.2. Coagulation
2.2.2.1.Mechanism of Coagulation Coagulation is the process of destabilizing of the colloidal or suspended particles which are stable (N. Haas, J. Vamos, 1995, p. 144). Coagulation process is made by the addition of coagulants, which reduce or neutralize the repulsive force between particles so that the particles will approach and combine. To neutralize or reduce the charges between particles, the suspension is rapidly agitated after the addition of coagulant in short time. The agitation of the destabilized particle causes particle destabilization. Coagulation is used for removing of the following parameters: •
organic and inorganic turbidity.
•
color
•
bacterial growth and pathogenic microorganisms
•
algae and organisms
•
phosphate
•
BOD and COD
15
•
suspended solids
•
metals
2.2.2.1.1. Factors of Effecting Coagulation There are two different factors that influence the coagulation most. A) Composition of wastewater: Coagulation process is mostly related with alkalinity, pH, turbidity, color and temperature. I.) Alkalinity: We can describe four types of suspensions.
High colloid concentration, low alkalinity: This is easiest system to treat. With relatively small dosages of coagulant, water of this type should be easily coagulated by adsorption and charge neutralization. Depression of pH makes this method more effective, since the aquometallic ions are more effective at lower pH values. However, care should be used to prevent excessively low pH.
Low colloid concentration, low alkalinity: Coagulation is most difficult in such systems. Additional alkalinity, additional colloidal particles, or both must be added to provide effective coagulation. Because the small number of colloids make coagulation difficult, and low alkalinity prevents effective Al(OH)3 formation. Additional colloidal particles can be added to convert this water to that of group 1 which is high colloid concentration, low alkalinity, or additional alkalinity can be added to convert it to a group 4 type, which is low colloid concentration, high alkalinity. It may be advantageous to add both colloid particles and alkalinity.
High colloid concentration, high alkalinity: Here the engineer can elect to use a high coagulant dosage due to the high alkalinity. Alkalinity can be removed by washing and destabilize with a lower coagulant dosage at a lower pH. The pH will be relatively unaffected by coagulant addition. Because of the high alkalinity, adsorption and charge neutralization will be less effective than in waters of low alkalinity. Higher coagulant dosage should be used to ensure sweep coagulation.
16
Low colloid concentration, high alkalinity: Coagulation is accomplished with a relatively high coagulant dosage by enmeshment of colloidal particles in a “sweep floc”. Alternatively, a coagulant aid may be added to increase the colloidal concentration and increase the rate of interparticle contacts. The small number of colloids make coagulation difficult, even if the particle charge has been neutralized. The principal coagulation mechanism is sweep coagulation with moderate coagulant dosage. Addition colloidal particles may decrease the amount of coagulant needed. S. Peavy et la., 1985, pp. 140-141 II.) pH : The pH of the water could also determine/eliminate many treatment options. If the pH is higher than 8.5 and Dissolved Organic Carbon (DOC), often referred to as color, has to be removed a highly acidic coagulant that will driver the pH down to +7.0 will have to be considered. It may be necessary to add some soda ash in order to bring the Langlier Stability Index back to zero after such treatment. If the pH is acidic great care will have to be taken to ensure that the chemical reactions occur as desired and that the finished water is stable, removal of co lour will be easy. Ferric salts often perform well in acidic conditions. The most challenging conditions occur when co lour has to be removed from a water that has a high pH and a low alkalinity. Careful depression of pH without alkalinity destruction can be realized if gaseous CO2 and Ca(OH)2 are added together. The choice of coagulant will determine the extent to which pH has to be depressed. This is a somewhat sophisticated approach and would not be recommended for a smaller community with a restricted capital budget. III.) Turbidity: The precipitation of mineral turbidity by the classic coagulation and flocculation process is well defined and reasonably straight forward. Turbidity can be classified as being anionic ally charged silica particles. Often the effect that turbidity has is dependent on the amount present rather than the classification. In low turbidity
17
waters (4
Slope of floor (%)
1
8
28
CHAPTER THREE
EXPERIMENTAL STUDIES
3.1. Experimental Setup
3.1.1. Jar Test Apparatus The jar test is a common laboratory procedure and simulates the coagulation and flocculation processes in bench scale. It is used to determine the optimum operating conditions such as pH, temperature, chemical dose, etc., for water or wastewater treatment. This method allows adjustments in pH, variations in coagulant or flocculant dose, alternating mixing speeds, or testing of different coagulant or flocculant types, on a small scale. Throughout the laboratory studies Stuart Scientific Flocculator 5W1 was used (see Figure 3.1). The jar testing apparatus contains six paddles which stir the contents of six 1 liter containers (beaker). A rpm gage at the top-center of the device permits the uniform control of the mixing speed (i.e. 200400 rev/min for coagulation/rapid mixing and 10-100 rev/min for flocculation/slow mixing) for all containers. In the thesis, jar test procedure consists of four consecutive steps; 1. Filling of the beakers with raw wastewater 2. Addition of coagulants to each beaker with varying doses and stirring approximately 203 rpm for 1 minute to disperse the coagulant 3. Reducing the stirring speed to 24 rpm for 45 minutes to promote floc formation by enhancing particle collisions which lead to larger flocs. Here, speeds are slow enough to prevent sheering of the floc due to turbulence caused by stirring to fast.
29
4. Turning off the mixers to allow the containers for settling for 30 to 45 minutes.
(a)
(b) Figure 3.1 (a) Schematic representation of jar test apparatus, (b) Photograph of jar test apparatus
30
3.1.2. Air Flotation Apparatus In the experimental studies, the effectiveness of the air flotation process was also examined to remove solid particles from the wastewater. For this purpose, Armfield type aeration apparatus was used to simulate the flotation process in a small scale (see Figure 3.2).
Figure 3.2 Aeration Apparatus
Apparatus contains 1.5-liter container made from plexiglas material, and equipped with ceramic diffuser, air pump and flow meter. During the experiments, container was filled with raw wastewater as first, and then the air was introduced via diffuser from bottom part of the apparatus by air pump. The air flow rate was around 4.5 l/min. At the end of the 30 minutes aeration, air pump was turned off.
3.1.3. Imhoff Cone In order to indicate whether the settling process is functioning properly for wastewater samples, imhoff cone was used in the study. The schematic representation of imhoff cone is given in Figure 3.3. It is made from plastic material and graduated from 0-1000 mL. The main procedure of the test starts with filling of the raw wastewater to the imhoff cone to the one-liter mark, and then settling of the
31
sample in the apparatus for a reasonable period. In this study, the time which is required for settlement of the particles was taken as 2 hours.
Figure 3.3 Imhoff Cone
3.2. Experimental Procedure Experimental studies were performed to investigate the effectiveness of starch and kaolin in wastewater treatment. The treatment performance of each chemical was examined for various treatment methods such as coagulation / flocculation / sedimentation (CFS), air flotation and sedimentation. In CFS process, starch and kaolin wee used as coagulant as first. Throughout the experiments alum, lime and FeCL3 wee also used especially comparison purpose. The optimum doses of all materials were determined via jar testing. COD (Chemical Oxygen Demand) measurements were used for the decision of the optimum dose. Experimental procedure draw on the first step (determination of optimum coagulant doses) is summarized below;
32
Each beaker was filled up 1-liter wastewater samples and increasing doses of coagulants were added to the beakers carefully. Then, typical jar test procedure (rapid and slow mixing, settling) explained in Section 3.1.1 was initiated. Jar test was repeated for each chemical and optimum doses were designated. Since the experiences on starch and kaolin in wastewater treatment is rare, investigation of optimum pH ranges for starch and kaolin were also carried out. In the next stage of CFS process, chemicals were experienced as flocculant. Besides the starch and kaolin, two different polyelectrolytes were also used in the experiments for comparison purpose. Experimental procedure employed in this stage (determination of optimum flocculant doses) is summarized below; Each beaker was filled up 1-liter wastewater samples. Optimum dose of coagulant is added to the each beaker and stirred at 203 rpm for 1 minute. Following to coagulation, slow mixing at 24 rpm for 45 minutes was applied. Here, starch and kaolin was used as natural flocculant and compared with the synthetic polymers. Flocculant doses were adjusted as 1-10 mg/L. This procedure was applied for each coagulant, i.e. alum, FeCl3, and lime respectively. The effect of starch and kaolin to flotation process was also investigated in this study. For this purpose, flotation equipment shown in Figure 3.2 was used, and the simple procedure aforementioned in Section 3.1.2 was performed. In order to determine the performance of flotation process without the additives plain air flotation was also experienced. For chemically flotation alternative, optimum doses of each chemical found at previous stage were used. Throughout the laboratory studies, the effect of sedimentation on treatment was also investigated. Plain sedimentation and chemical precipitation with HCl were used in the experimental studies. For this purpose, Imhoff cone and the simple procedure mentioned in Section 3.1.3 was used.
33
Finally, combination of sedimentation and CFS process was studied in the thesis. Following to primary sedimentation, wastewater samples were subjected to CFS process. Optimum coagulant doses obtained in the first stage was used in CFS process. And, the treatment performance of each stage was determined separately. All those experimental work were performed using the wastewater samples taken from two corrugated box industries located in Kemalpasa region. Characteristics of the wastewaters are given in following sections. Optimum dose investigations were based on COD (Chemical Oxygen Demand) removal efficiencies. Besides the COD analysis pH, TS (Total Solids), Turbidity and Color parameters were also measured during the study. And, oil & grease, SS (Suspended Solids) parameters were measured only for optimum doses.
3.3. Experimental Analysis The parameters measured during the experiments were as follows: •
Chemical oxygen demand (COD)
•
Total solids (TS)
•
Turbidity
•
Color
•
Suspended solids (SS)
•
Oil & Grease
•
pH
•
Temperature
•
Total Nitrogen (TN) and Total Phosphorus (TP)
In order to measure the organic matter content of samples COD measurements were carried out according to Standard methods (APHA, 1989). Closed reflux colorimetric method described in Appendices more detail was used in COD analyses. Total solids which refer all types of solid constituents in wastewater, were measured by evaporating a water sample in a weighed dish, and then drying the residue in an
34
oven at 103 to 105o C. Suspended fraction of solid matter that can be removed from the wastewater by sedimentation or filtration, were carried out according to the Standard Methods, method 2540 D. Membrane filter papers (GF 52 Glass Fiber paper, Ф 47 mm, ref no: 428226) were used in the measurements. Turbidity measurement was also carried out to acquire an idea on suspended maters. During the experimental studies, a turbidimeter named as HACH DC 144 69 DR was used. Since the wastewater sample taken from painting process is highly colored, color measurements were achieved to determine the color removal efficiency of the chemicals. During the experimental studies, HACH DC 144 69 DR Colorimeter was used. In addition, oil and grease was measured by extraction with solvent (Standard Methods, 1989). Temperature and pH are routine parameters which of measured throughout the experiments. Solo Mat 520C pH meter was used both pH and temperature measurements. And, finally, Total nitrogen and phosphate phosphorus concentrations were determined by using the test kits (Merck No: respectively 14537 and 14543) and a Merck SQ 300 spectrometer. As regards to measurements, detailed information on methods is given in the Appendixes.
3.4. Wastewater Characterization Experimental studies were performed mainly with two types of wastewater, i.e. domestic and industrial. Throughout the experiments, wastewater samples were taken from two different corrugated box factories. In general, process wastewater is produced from corrugated board making and printing operations The production diagram is given in the appendixes. The wastewater coming from the washing of corrugating machine contains adhesive materials such as starch, borax and caustic, whereas wastewater from printing machines contains dyes. Thus, wastewater generated from corrugated box production includes organic substances, solid matters, oil and grease, and is colored in general. The wastewater collection system of each industry is different. Separate wastewater collection system which enables the wastewater sampling from each process separately is used in the first industry
35
examined in the thesis. Therefore, wastewater originated from corrugated box production and printing processes were taken before the treatment plant of the factory. Here, wastewater generated from corrugated box production and printing processes is called as WW1 and WW2, respectively. Alternatively, combined system is used for collection of wastewater generated in the second industry. Therefore, wastewater contains adhesive materials, dyes, and other substances generated from corrugated and printing machines, and domestic facilities. Wastewater samples are taken from equalization tank. Hereafter wastewater samples are shortly called as WW3 in the study. Domestic wastewater generated from toilets, showers, kitchens, etc can be taken separately from the first examined industry due to separate collection system. In this study, domestic wastewater is shortly called as WW4. Throughout the experimental studies wastewater samples taken from their sources are conveyed to the laboratory within the same day. And, characterization studies are carried out for each wastewater as first. The results of the characterization studies are summarized in Table 3.1.
Table 3.1 Characterization of wastewaters used in the experimental studies Parameters Temperature
Unit
WW 1
WW 2
WW 3
WW 4
0
24,9-26
24,9
28-28,5
25
7,01-5,51
7,37-7,25
6,54-7,8
7,07-7,61
C
pH
-
Turbidity
JTU
65-165
50400-170000
260-112000
85-380
Color
CU
195-250
104000-352500
560
250
COD
mg/L
839-1513
12024-56875
1130-78000
157-5107
TS
mg/L
1688-2956
6064-18456
2336-8320
692-1164
SS
mg/L
40-110
10000-24000
480-16000
70-1164
Oil & Grease mg/L
44-144
5900-11000
128-6380
44-314
TN
mg/L
3,2-5,0
255-1020
240-500
104
PO4-P
mg/L
0,4-3,0
9,5-408
440-490
9,2
36
3.5. Chemicals Used in the Experimental Studies
3.5.1. Starch
3.5.1.1. General Properties of Starch Starch is a carbohydrate polymer occurring in granular form certain plant species notably cereals, tubers, and pulses such as corn, wheat, rice, tapioca potato, pea etc. The polymer consists of linked anhydro-a-D-glucose units. It may have either a mainly linear structure (amylose) or a branched structure (amylopectin). A single plant species may exist as hybrids with various proportions of amylose and amylopectin e.g. high amylose corn. In addition, summary of physical and chemical properties of starch is presented below; Raw Materials: Potato, cassava, corn and wheat are the dominant starch raw materials. They are renewable and challenge the present role of oil as the future source of energy and industrial polymer. Moisture content: The moisture content of starches, which are sold commercially, may be different. For example, cornstarch is usually supplied at 11% 13% moisture whereas potato starch has 18% - 20% moisture. Low moisture starches are available to meet specific requirements with moisture contents below these levels, and special packaging is needed to avoid moisture pick-up from the atmosphere. Taste: In general, the taste of starch or modified starch for food use must be as close to neutral as possible; this is particularly critical for dairy products, e.g. yogurt. Off flavors can arise in modified starches and may be related to insufficient washing or the saponification of the naturally occurring fatty acids in the starch granule during chemical modification.
37
Texture: The texture of a starch paste is related to the starch type and the presence of any physical or chemical modification. The range of texture may extend from short and smooth which is characteristic of a crosslinked starch, or long, tacky, and cohesive which is typical for native tuber starch pastes and overcooked starches. Whiteness: The apparent whiteness of the surface of starch powder, determined by reflectance in comparison to a known standard surface. Fluidity: It is the inverse of viscosity. The higher the number, the more hydrolyzed the starch. Water has a value of 100. Thin-boiling starches used in candy are in the range of 60 to 75. Oxidized and acid-thinned starches and dextrins are all manufactured to various fluidity values. Lipids: Although lipids are mostly removed from corn as oil during the wet milling process there is a low level (up to 1%) of residual lipid (fat) present in starch. Potato and tapioca starch contain lower lipid levels than cornstarch.
Other Properties of starch: Surface of starch granules app. 30 ha/g Specific density app. 1.55 g/ml Specific heat 1.22 J/g Bulk weight of starch 80% DS app. 0.7 g/ml DS of moist centrifuged app. 0.6 g/ml Brightness (MgO2 = 100%) app. 95 %
3.5.1.2. Types of Starch There are two different kinds of starch. One of them is native starch and the other one is modified starch. During this thesis, physically modified starch was used.
38
Native starch: Starch recovered in the original form (i.e. unmodified) by extraction from any starch-bearing material. In order to distinguish unmodified starch from starch, it has undergone physical or chemical modification. More recently, new types of native starches have been developed with many of the properties of modified food starches. Some examples can be given for this family. These are cereal starch, cornstarch, potato starch, rice starch, sago starch, Tapioca (cassava) starch.
Modified starch: Starch which has been treated physically or chemically to modify one or more of its key physical or chemical properties. see Chemically and physically modified starch entries. This term is used to declare starches on food labels in certain European countries.
3.5.1.3. Starch Products Starch is used in many places in various sectors. These sectors are given with the products of starch below. Food industry: Snacks, baking, baby food, noodles, sauces, meat products and low calorie foods. Beverages industry: Soft drinks, beer, alcohol, and instant coffee. Confectionary:
Ice
cream,
confectionery
candy,
high-boiled
sweets,
marshmallows, marmalade, jam, and canning. Water Treatment: Starch products are used as flocculants in many industrial water treatment plants for flocculation purposes. Coal: Briquettes made of coal dust and fines are bound with starch as a binder. Detergent: Starch finds use as a re-deposition inhibitor of dirt once it has been released from the fabric.
39
Pharmacy: Starch acts as a binder in pharmaceutical tablets and as a disintegrating agent as well. Special starch is used as dusting powder and surgical glove powder. Agriculture: Copolymerizing starch with acrylonitril and alkaline hydrolysis gives a super absorbing polymer, "Super-Slurper" used for coating of seeds to improve presence of water for faster germination and to improve water capacity of soil for potted plants. Stain remover: To remove a stain with an absorbent powder, sprinkle a layer of starch powder over the stain. Spread the starch round, and as soon as it becomes gummy lift, shake or brush it off. Repeat this until nothing further is being absorbed. If a mark still remains after this, mix the powder to a paste, using water for nongreasy stains and a grease solvent (see "for greasy marks"). Leave standing till dry, and then brush off. Dusting powders: Dusting powder consists of finely powdered substances free of grittiness. They are used on normal intact skin prophylactically to reduce friction (talc) or moisture (starch). By cross-linking starch can be stand sterilising in autoclave and be used as surgical dusting powder. Paper: Thin-boiling starches are used as sizing on most paper. Cationic starches are used as wet-end additives improving filler retention and reducing effluent load. Starch is used for coating. Corrugated board: Native starch in mixture with pregelatinized starch is applied on top of the corrugated flute before lining. The native starch acts as instant glue with good tack when heat is applied. Cardboard may be produced by gluing liners together with a starch-based glue.
40
Textile: Starch is used for sizing yarn to improve abrasion resistance in fast looms. Starch is used for finishing fabrics to add feel, stiffness or to provide a good printing surface. Thin-boiling starches are preferred. Plastics & Packaging: In plastics starches improve the biodegradability of plastic and finished products. Foamed Starch: Starch can be environmentally friendly blown into a foamed material using water steam. Foamed starch is antistatic, insulating and shock absorbing, therefore a good replacement for polystyrene foam. It can be used as packaging material or can be pressed into starch-based sheet for thin-walled products, such as trays, disposable dishes, cups etc or used as loose-fill for packaging. It offers numerous disposal alternatives and can be a good substitute of CFCs-blown PS.
3.5.2. Kaolin
3.5.2.1. Geology of Kaolin Kaolin is formed by two fundamental processes; weathering and chemical alteration of a parent rock. These processes remove most elements from the parent rock, apart from the constituents of the clay, the silicon, aluminum, oxygen, and hydrogen. Primary kaolin deposits are usually the result of the situ weathering of feldspar – rich rocks or hydrothermal processes. Secondary kaolin consists of sedimentary deposits, which have either been transported and re-deposited or altered from previously transported material. Individual kaolins may differ in much respect due to variations in a number of kaolinit properties, including degree of crystallinity and particle size, shape and distribution. Crystallinity impacts on the brigtness, whiteness, opacity, gloss, and viscosity properties of the material. Particle size, shape and distribution influence the smoothness, optical, deformation and flow properties.
41
3.5.2.2. Characterization of Kaolin Kaolin is a soft, fine, white clay composed mainly of kaolinit, (Al4Si4O10 (OH)8). It is formed through the alteration or “kaolinisation” of feldspar-rich parent rocks by either weathering or hydrothermal processes. The ultimate breakdown product of most rock-forming minerals is kaolinit. Kaolin usually contains some free quartz as well as subsidiary resistant minerals derived from the parent source. Kaolinite occurs as hexagonal platy crystals up to several hundred microns across.
Table 3.2. The properties of kaolin used in the experiments (%) Chemical Analysis SiO2
≤50.00
Physical Properties Brightness
(Elrepho
457)
Values R
85 ± 2
Al2O3
≥30.00
Yellowish
6 ±1
Fe2O3
≤0.50
Humidity (at 105 oC)
≤%7
TiO2
≤0.60
pH (5%)
K2O
≤3.30
Surface Area
15-25 m2/g
CaO + MgO
≤1.00
Total Density
0,50-0,60g/cm3
Na2O
0.15
Appearance
6.5 – 8.0
Powder
3.5.2.3. Uses of Kaolin Kaolin has a wide range of uses, including paper coating and filling, in the manufacture of ceramics and refractory ware, as a filler and extender in plastics rubber, paints, inks, food additives, cosmetics, insecticides, and filter aids, and as an ingredient in pharmaceutical products.
42
The paper industry in the major consumer of kaolin with approximately 50% of world production being used paper products. The material is used as both filler and surface coating. Paper quality kaolin must be less then 2 microns in size and possess a fairly flat platy crystal structure. In the rubber and plastics industry, kaolin is used as a filler and extender. The inclusion of kaolin in the rubber matrix improves the strength durability and rigidity of the compound. In plastics, kaolin provides smoother surfaces, dimensional stability and resistance to chemical attack. Kaolin is used in the paint industry as a extender that provides improved flow properties, high covering power, brightness and increased durability to wear. Calcined and water-beneficiated kaolin are used in both water and oil based paints. Kaolin is traditionally used in the ceramics industry. When fired is produces a white porcelain or china, which is utilized in whiteware, wall tiles, refractories, face bricks and insulators.
3.5.3. Alum Aluminum can be purchased as either dry or liquid alum [Al2(SO4)3. 14H2O]. Commercial alum is sold as approximately 48.8 percent alum (8.3 %Al2O3) and 51.2 percent water. If it is sold as a more concentrated solution, there can be problems with crystallization of the alum during shipment and storage. Approximately 48.8 percent alum solution has a crystallization point of-15.60C. Approximately 50.7 percent alum solution will crystallize. At +18.30C . Dry alum costs about 50 percent more than an equivalent amount of liquid alum so that only users of very small amounts of alum purchase dry alum. Two important factors in coagulant addition are pH and dose. The optimum dose and pH must be determined from laboratory tests. The optimal pH range for alum is
43
approximately 5.5 to 6.5 with adequate coagulation possible between pH 5 to pH 8 under same conditions. An important aspect of coagulation is that the aluminum ion does not really exist as Al3+ and that the final product is more complex than Al(OH)3 . When the alum is added to the water, it immediately dissociates, resulting in the release of an aluminum ion surrounded by six water molecules. The aluminum ion immediately starts reacting with the water, forming large Al.OH.H2O complexes. Some have suggested that it forms [Al8(OH)20.28H2O]4+ as the product that actually coagulates. Regardless of the actual species that is produced, the complex is a very large precipitate that removes many of the colloids by enmeshment as it falls through the water. This precipitate is referred to as a floc. Floc formation is one of the important properties of a coagulant for efficient colloid removal.
3.5.4. Ferric Chloride Iron can be purchased as either the sulfate salt (Fe2(2O4)3H2O) or the chloride salt (FeCl3.xH2O). It is available in various forms, and the individual supplier should be consulted for the specifics of the product. Dry and liquid forms of ferric chloride are available. The properties of iron with respect to forming large complexes, dose, and pH curves are similar to those of alum. Ferric salts generally have a wider pH range for effective coagulation than aluminum, that is, pH ranges form 4to 9.
3.5.5. Lime
3.5.5.1. Geological Description of Limestone Limestone is a sedimentary rock composed mainly of calcium and magnesium carbonate. It is formed by the deposition either of the skeletons of small creatures and/or plants (organic limestone), or by chemical precipitation, or by deposition of fragments of limestone rock, on the beds of seas and lakes. Limestone is contaminated to a greater or lesser extent by the deposition of sand. The purest
44
carbonates and the most suitable from the production point of view tend to be the thick-bedded type. Limestone is made up of varying proportions of the following chemicals with calcium and magnesium carbonate being the two major components. Calcium carbonate
CaCO3
Magnesium carbonate
MgCO3
Silica
SiO2
Alumina
Al2O3
Iron oxide
Fe2O3
Sulphate
SO3
Phosphorus
P2O5
Potash
K2O
Soda
Na2O
For a general purpose lime, a limestone with an SiO2 content of up 3.5% and Al2O3 content of up to 2.5% may be used where purer stone is not available, whereas lime for building or road construction purposes may have an SiO2 content of up to 10% (perhaps slightly more) and anAl2O3 content of 5%. An Al2O3 proportion of greater than 5% will produce a semi-hydraulic or hydraulic lime.
3.5.5.2. Physical Characteristics of Limestone The color of most limestone is varying shades of gray and tan. The grayness is caused by the presence of carbonaceous impurities and the tan by the presence of iron. It has been found that all limestone are crystalline but with varying crystal sizes, unit formity, and crystal arrangement. These ret suits in stone with a corresponding variance in density and hardness. For lime, production purposes there are two factors related to limestone crystallinity and crystal structure, which are of specific interest.
45
Density or porosity is determined as the percentage of pore space in the stone’s total volume. It range from 0.3% - 12%. At the lower end are the dense types (marble), and at the upper the more porous (chalk). Generally, the finer the crystal size, the higher the porosity but there are anomalies, which suggest that each case be considered separately. A high porosity makes for a relatively faster rate of calcinations and more reactive quicklime. Limestone varies in hardness from between 2 and 4 on Moh’s scale with dolomitic lime being slightly harder than the high calcium varieties. Limestone is in most cases soft enough to be scratched with a knife. Due to the variance in prosity, the bulk densities of various limestone range from 2000kg/m3 for the more porous to 2800 kg/m3 for the densest. The specific gravities of limestone range from 2.65-2.75 for high calcium limestone and 2.75-2.9 for dolomitic limestone. Chalk has a specific gravity of between 1.4 and 2. Lime is produced from limestone by calcinations and hydration reactions. These reactions are given below:
Calcination
High calcium limestone:
CaCO3 + heat → CaO + CO2↑
Magnesia limestone: Ca Mg (CO3) 2 + heat → CaCO3 + MgO + CO2↑(at around 750 °C) CaCO3 + heat → CaO + CO2↑(at around 1100°C) Hydration CaO + H2O → Ca (OH) 2 (water) MgO + H2O → Mg (OH) 2 (water)
46
3.5.6. Polyelectrolytes Polyelectrolytes are substances containing macromolecules carrying a large number of ionic charges, the polyions with the small counter ions which render the system electroneutral".
3.5.6.1. Polyelectrolyte 1 Appearance: white powder Mesh size: 1.25 mm App bulk density: 0.80 Brookfield viscosity: 5.0-g/l
1700 cps
: 2.5-g/l
650 cps
: 1.0 g/l
300 cps
Max concentration available: 5 g/l Usual stock solution concentration: 3 g/l Dissolution time: 60 minutes Stability of the deionized water solution: 10 days Stability of the dry product: 24 months Packaging: polyethylene sacks, 25 kg
3.5.6.2. Polyelectrolyte 2 PRAESTOL 2540 is used mainly for flocculation of mineral and hydroxide type solid particles and colloids, preferably for clarification of washing water in the treatment of mining raw materials, such as hard coal, rock salt, sand, gravel and clay. It is also used in the metal producing and processing industries and in the chemical industry. These applications usually involve the flocculation of very tine to colloidal solid particles suspended in neutral to alkaline slurries, which contain mainly inorganic solids, substantially tree of high valency metallic ions (e.g. Al3+, Fe3+).
47
Other applications include the treatment of surface and ground water, and all types of wastewater, after preliminary treatment with hydroxide forming substances. When used as a sedimentation accelerator or clarifying agent (in static sedimentation processes), only a few grams of PRAESROL 2540 per cubic meter of the slurry to be clarified are required , in mechanical sludge dewatering, in order to achieve a high machine throughput and a discharge water tree of settleable solid materials, approx, 100 g/m3 of wet sludge are required.
Product Description Composition: High molecular, medium anionic polyelectrolyte based on polyacrylamide Supply form: white granular material Charge type: medium anionic Bulk density: approx. 700 kg/m3 Effective in pH range: 6-13
48
CHAPTER FOUR
EXPERIMENTAL RESULTS
4.1. Coagulation / Flocculation / Sedimentation (CFS) Process
4.1.1. Use of Various Chemicals as Coagulant in CFS Process At the beginning of the experimental studies starch and kaolin were used as coagulants. Besides, in order to compare the effectiveness of these two chemicals with more conventional ones alum, ferric chloride and lime were also used as coagulant for comparison purpose. The optimum doses of each chemical were determined by COD parameter. In addition to the COD parameter, Total Solids (TS), Turbidity, pH and Color parameters were measured for every sample whereas Suspended Solids (SS) and Oil & Grease analyses were measured only for the samples having optimum coagulant dose.
4.1.1.1. Starch Throughout the experimental studies starch was experienced as coagulant for WW1, WW2, WW3 and WW4 in order to observe the treatment efficiency. Starch doses were maintained as 10, 25, 50, 100, 250 and 400 mg/l. The results of the experiments relating to WW1 are presented in Table 4.1. Similar experiments were achieved for WW2, WW3 and WW4. Starch dosing was kept between 25 to 2000 mg/l, 10 to 500 mg/l, and 10 to 400 mg/l, for wastewaters WW2, WW3 and WW4, respectively. The results are presented in the order of Tables of 4.2, 4.3 and Table 4.4 for wastewaters WW2, WW3 and WW4.
49
Table 4.1 Utilization of starch as coagulant in CFS process for WW1 Parameter
Starch Dose (mg/L)
Units 0
10
25
50
100
250
400
555
275
315
335
275
375
COD
mg/L 1513
TS
mg/L 1688 1400 1376 1576 1360 1336 1340
Turbidity
JTU
165
0
0
0
0
0
0
SS
mg/L
40
-
110
-
-
-
-
Oil & Grease mg/L
144
-
124
-
-
-
-
7,01
7,18
7,30
7,16
7,19
7,09
7,06
-
pH
Table 4.2a Utilization of starch as coagulant in CFS process for WW2 Parameter
Starch Dose (mg/L)
Units 0
25
50
100
250
400
500
COD
mg/L
56875
11963 11743 10765 11222 11497
9002
TS
mg/L
6064
2766
5232
Turbidity
JTU
50400
13643 15641 15338 15641 24218 20400
Color
CU
104000 49580 55200 49513 55200 55535 50400
SS Oil & Grease pH
3393
2787
2933
3162
mg/L
10000
-
-
-
-
-
-
mg/L
5900
-
-
-
-
-
-
-
7,30
7,11
7,11
7,12
7,14
7,15
7,16
50
Table 4.2b Utilization of starch as coagulant in CFS process for WW2 (Cont.) Parameter
Starch Dose (mg/L)
Units 0
800
1000
1200
1500
2000
COD
mg/L
56875
9504
8701
8500
10306
11510
TS
mg/L
6064
4236
5784
5904
6000
5812
Turbidity
JTU
50400
22200
19200
16800
18600
22800
Color
CU
104000
55200
49200
42000
49200
55200
mg/L
10000
-
-
2400
-
-
mg/L
5900
-
-
4500
-
-
-
7,30
7,17
7,17
7,21
7,18
7,18
SS Oil & Grease pH
Table 4.3 Utilization of starch as coagulant in CFS process for WW3 Parameter
Starch Dose (mg/L)
Units 0
10
25
50
100
250
500
COD
mg/L 78000 60000 54000 40000 38200 10000 53000
TS
mg/L
4672
Turbidity
JTU
68000 50000 50000 50000 45000 40000 49000
SS
mg/L 16000
Oil & Grease mg/L pH
-
4560
4412
4504
4480
4656
4712
-
-
-
-
3600
-
2000
-
-
-
-
780
-
7,65
7,74
7,72
7,74
7,70
7,68
7,66
51
Table 4.4 Utilization of starch as coagulant in CFS process for WW4 Parameter
Starch Dose (mg/L)
Units 0
10
25
50
100
250
400
COD
mg/L 1107
969
909
868
1132
984
1185
TS
mg/L 1164
924
932
908
928
928
832
Turbidity
JTU
380
130
120
130
135
140
135
SS
mg/L
120
-
-
112
-
-
-
Oil & Grease mg/L
314
-
-
3
-
-
-
7,45
7,47
7,44
pH
-
7,61
7,48 7,47 7,47
4.1.1.1.1. Finding the Optimum pH Range of Starch Throughout the experimental studies, starch pH ranges that the starch works best as a coagulant was determined WW1 and WW3 in order to observe the treatment efficiency. Optimum starch doses that were obtained in the previous section were used in this section. The results are presented in Table 4.5 for WW1 and WW3. HCl and NaOH were used for pH adjustment.
52
Table 4.5 Investigation of optimum pH ranges for starch (optimum dose of starch, WW1=25mg/l and WW3=250mg/l) Parameters
TS
Oil&Grease pH
mg/l
JTU
mg/l
mg/l
-
Influent
1513
1688
165
40
144
7,01
pH10
Influent 78000 4672 pH10
4.1.1.2. Kaolin Throughout the experimental studies kaolin was used as coagulant for WW1, WW2, WW3 and WW4 in order to observe the effectiveness on treatment. Kaolin doses were maintained as 10 to 400 mg/l for WW1, and the results of these study in Table 4.6. For WW2 and WW3, kaolin doses were adjusted as 10 to 1200 mg/l, and the results are given in Table 4.7, Table 4.8, respectively. Finally, the results for WW4 are presented in Table 4.9.
53
Table 4. 6 Utilization of kaolin as coagulant in CFS process for WW1 Parameter
Kaolin Dose (mg/L)
Units 0
10
25
50
100
250
400
839
759
619
649
569
549
790
COD
mg/L
TS
mg/L 2956 2972 2964 2944 2764 2520 2192
Turbidity
JTU
65
40
65
70
85
115
140
Color
CU
195
160
185
190
205
300
351
mg/L
110
-
-
-
-
60
-
Oil & Grease mg/L
44
-
-
-
-
36
-
5,51
5,65
5,65
5,65
5,66
5,57
5,58
SS
pH
-
Table 4.7a Utilization of kaolin as coagulant in CFS process for WW2 Parameter
Kaolin Dose (mg/L)
Units 0
10
25
50
100
250
COD
mg/L
41575
7795
3302
2487
4120
3302
7TS
mg/L
18456
15956
12580
13180
11350
14700
Turbidity
JTU
170000 104000 108000 102000 106000
84000
Color
CU
352500 238000 248000 238000 247200 184000
mg/L
24000
-
-
-
-
-
Oil & Grease mg/L
11000
-
-
-
-
-
7,37
7,21
7,21
7,17
7,27
7,21
SS
pH
-
54
Table 4.7b Utilization of kaolin as coagulant in CFS process for WW2 (Cont.) Parameter
Kaolin Dose (mg/L)
Units 0
400
600
800
1000
1200
COD
mg/L
41575
2077
1994
1829
1497
3071
TS
mg/L
18456
7428
8196
6900
6080
7236
Turbidity
JTU
170000
64000
66000
46000
50400
44000
Color
CU
352500 160000 164000 122000 128000 108000
mg/L
24000
-
-
-
20000
-
Oil & Grease mg/L
11000
-
-
-
960
-
7,37
7,18
7,04
7,02
7,07
7,08
SS
pH
-
Table 4.8a Utilization of kaolin as coagulant in CFS process for WW3 Parameter
Kaolin Dose (mg/L)
Units 0
10
25
50
100
250
COD
mg/L
1103
986
983
996
945
879
TS
mg/L
2336
2276
2208
2140
2112
1788
Turbidity
JTU
260
20
30
35
30
50
Color
CU
560
75
80
100
100
120
mg/L
480
-
-
-
-
-
Oil & Grease mg/L
128
-
-
-
-
-
6,54
6,85
6,82
6,80
6,74
6,67
SS
pH
-
55
Table 4. 8b Utilization of kaolin as coagulant in CFS process for WW3 (Cont.) Parameter
Kaolin Dose (mg/L)
Units 0
400
600
800
1000 1200
382
399
COD
mg/L
1103
602
482
TS
mg/L
2336
1648
1608 1464 1292 1188
Turbidity
JTU
260
40
98
90
90
90
Color
CU
560
110
37
42
36
33
mg/L
480
-
-
40
-
-
Oil & Grease mg/L
128
-
-
39
-
-
6,54
6,62
7,44
7,43
7,47
7,45
SS
pH
-
498
Table 4.9 Utilization of kaolin as coagulant in CFS process for WW4 Parameter
Kaolin Dose (mg/L)
Units 0
10
25
50
100
250
400
COD
mg/L
157
133
126
86
103
109
123
TS
mg/L
692
620
664
636
608
588
512
Turbidity
JTU
85
110
110
105
115
120
115
Color
CU
250
250
325
320
320
325
305
mg/L
70
-
-
50
-
-
-
Oil & Grease mg/L
44
-
-
36
-
-
-
SS
pH
-
7,07 7,09 7,05 7,10 7,09 7,01 6,99
4.1.1.2.1. Finding the Optimum pH Range of Kaolin Throughout the experimental studies, kaolin pH ranges that the kaolin works best as a coagulant was determined WW2 and WW4 in order to observe the treatment efficiency. Optimum starch doses that were obtained in the previous section were used in this section. The results are presented in Table 4.10 for WW2 and WW4. HCl and NaOH were used for pH adjustment.
56
Table 4.10 Investigation of optimum pH ranges for kaolin (optimum dose of starch, WW2=1000mg/l and WW4=50mg/l) Parameters
COD
TS
Turbidity Color
SS
Oil&
pH
Grease mg/l
Units
mg/l
Influent 41575 18456 pH10
2950
8440
150000
250000 22000
9900
11,1
Influent
157
592
115
290
220
102
7,19
pH10
600
-
9560
changes
500
mg/l
1540
No pH
WW4
JTU
4.1.1.3. Alum As it stated above, treatment performance of starch and kaolin have been compared with the alum, lime and ferric chloride that are prevalent chemicals used in the treatment plants. Throughout the experimental studies alum was used as first as coagulant for each wastewater to compare its performance with the starch and kaolin. Alum doses were maintained as 10 to 400 mg/l for WW1, and the results are presented in Table 4.11. Similar investigations were carried out for each wastewater, and the results of those studies are given in Tables 4.12, 4.13, and 4.14, respectively.
57
Table 4.11 Utilization of alum as coagulant in CFS process for WW1 Parameter
Alum Dose (mg/L)
Units 0
10
25
50
100
250
400
455
275
215
355
175
255
COD
mg/L 1513
TS
mg/L 1688 1436 1464 1464 1396 1372 1524
Turbidity
JTU
165
0
0
0
0
0
0
SS
mg/L
40
-
-
-
-
12
-
Oil & Grease mg/L
144
-
-
-
-
16
-
7,01
6,85
6,81
6,77
6,64
6,44
6,07
pH
-
Table 4.12a Utilization of alum as coagulant in CFS process for WW2 Parameter
Alum Dose (mg/L)
Units 0
10
25
50
100
COD
mg/L
56875
5497
6997
6877
6357
TS
mg/L
6064
2600
3288
3948
2820
Turbidity
JTU
50400
16000 13000 14750 10250
Color
CU
104000 33500 30500 32000 24000
mg/L
10000
-
-
-
-
Oil & Grease mg/L
5900
-
-
-
-
7,30
7,32
7,31
7,24
7,18
SS
pH
-
58
Table 4.12b Utilization of alum as coagulant in CFS process for WW2 (Cont.) Parameter
Alum Dose (mg/L)
Units 0
250
400
500
600
COD
mg/L
56875
4916 1220
3500
5970
TS
mg/L
6064
2488 1196
1250
1260
Turbidity
JTU
50400
2500
260
14000 20000
Color
CU
104000 5150
600
9000
18000
mg/L
10000
-
160
-
-
Oil & Grease mg/L
5900
-
1230
-
-
7,30
7,05
6,95
6,90
6,80
SS
pH
-
Table 4.13 Utilization of alum as coagulant in CFS process for WW3 Parameter
Alum Dose (mg/L)
Units 0
10
25
50
100
250
COD
mg/L 78000 20000
8000
8800
14000 16000
TS
mg/L
4832
4276
4220
4016
Turbidity
JTU
63000 80000 70000 50000 30000 10000
SS
mg/L 10000
Oil & Grease mg/L pH
-
4304 -
24000 36000
2912
-
-
1200
-
120
-
-
-
7,65
7,74
7,72
7,74
7,70
7,68
Table 4.14 Utilization of alum as coagulant in CFS process for WW4 Parameter
Alum Dose (mg/L)
Units 0
10
25
50
100
250
400
COD
mg/L 1107
931
1396
852
1000
733
768
TS
mg/L 1164
748
1028
924
1084 1040
904
Turbidity
JTU
380
100
190
130
230
1
5
SS
mg/L
120
-
-
-
-
20
-
Oil & Grease mg/L
314
-
-
-
-
86
-
7,61
7,18
7,22
7,12
7,12
6,87
6,71
pH
-
59
4.1.1.4. Ferric Chloride (FeCl3) Ferric chloride was experienced as coagulant through the experimental studies for each wastewater for comparison purpose and the treatment efficiency of ferric chloride was investigated. The results of the study are presented in Table 4.15, 4.16, 4.17, and 4.18, respectively.
Table 4.15 Utilization of FeCl3 as coagulant in CFS process for WW1 Parameter
FeCl3 Dose (mg/L)
Units 0
10
25
50
100
250
COD
mg/L
1513
435
675
375
395
651
TS
mg/L
1688
2544
2964
5960
9876
15894
Turbidity
JTU
165
20
0
0
0
160
SS
mg/L
40
-
-
76
-
-
Oil & Grease
mg/L
144
-
-
140
-
-
-
7,01
2,72
2,54
2,30
2,03
1,71
pH
Table 4.16 Utilization of FeCl3 as coagulant in CFS process for WW2 Parameter
FeCl3 Dose (mg/L)
Units 0
10
25
50
100
250
400
2298
2165
COD
mg/L
56875
2566 2365 1529 1663
TS
mg/L
6064
1836 2460 5156 8444 16870 25744
Turbidity
JTU
50400
5
600
1150 1150
1000
700
Color
CU
104000
60
2000 5800 5600
4900
4700
SS
mg/L
10000
-
-
80
-
-
-
Oil & Grease
mg/L
5900
-
-
230
-
-
-
-
7,30
6,40
3,96
2,09
1,98
1,53
1,32
ml/l
0
420
500
400
470
500
538
pH Sludge Volume
60
Table 4.17 Utilization of FeCl3 as coagulant in CFS process for WW3 Parameter
FeCl3 Dose (mg/L)
Units 0
20
50
100
200
500
3200
17924
COD
mg/L
76000
32648 25000 15470
TS
mg/L
8320
16376 31728 59212 108640 216416
Turbidity
JTU
SS
mg/L
6800
-
-
Oil & Grease
mg/L
2020
-
-
7,54
ml/l
-
pH Sludge Volume
112000 73600 72000 32800
16800
18800
-
2860
-
-
-
140
-
1,49
1,26
0,97
0,64
0,17
900
620
600
460
400
Table 4.18 Utilization of FeCl3 as coagulant in CFS process for WW4 Parameter
FeCl3 Dose (mg/L)
Units 0
10
25
50
100
250
COD
mg/L
1107
615
541
871
908
894
TS
mg/L
1164
1684
3228
5080
9948
19468
Turbidity
JTU
380
500
340
270
450
550
SS
mg/L
120
-
190
-
-
-
Oil & Grease
mg/L
314
-
300
-
-
-
-
7,61
3,21
2,79
2,54
2,17
1,89
pH
4.1.1.5. Lime Finally, lime was used as coagulant for each wastewater to determine the treatment efficiency and compare the effectiveness of lime with the other chemicals, as well. During the experiments, lime doses were kept between 10 to 400 mg/l for WW1, WW2 and WW4. For the WW3 doses were maintained as10 to 250 mg/l. The results presented in tables from 4.19 to 4.22.
61
Table 4.19 Utilization of Lime as coagulant in CFS process for WW1 Parameter
Lime Dose (mg/L)
Units 0
10
25
50
100
250
400
COD
mg/L
1513
175
295
235
195
355
535
TS
mg/L
1688
1586
1405
1496
1510
1585
1576
Turbidity
JTU
165
0
0
0
0
0
0
SS
mg/L
40
84
-
-
-
-
-
Oil & Grease
mg/L
144
50
-
-
-
-
-
-
pH
11,38 11,21 11,27 11,40 11,52 11,80 11,90
Table 4.20 Utilization of Lime as coagulant in CFS process for WW2 Lime Dose (mg/L)
Parameter Units 0
10
25
50
100
250
400
COD
mg/L
56875
10510
10987 11210
9628
9777
10419
TS
mg/L
6064
6896
5232
6596
5884
3932
4616
Turbidity
JTU
50400
44000
36000 38000
40000
38000 36000
Color
CU
104000 100000 96000 96000 100000 96000 96000
SS Oil & Grease pH
mg/L
10000
-
-
-
-
1000
-
mg/L
5900
-
-
-
-
5000
-
-
11,16
10,80
10,90
10,98
11,02
11,38
11,53
62
Table 4.21 Utilization of Lime as coagulant in CFS process for WW3 Parameter
Lime Dose (mg/L)
Units 0
10
25
50
100
250
COD
mg/L
76000
36000
14000
6000
14000
16000
TS
mg/L
8320
6268
5928
6108
6148
6068
Turbidity
JTU
112000
50000
52000
48000
49000
45000
SS
mg/L
6800
-
-
2440
-
-
mg/L
6640
-
-
2020
-
-
-
7,54-11,0
10,10
10,12
10,17
10,29
10,73
Oil & Grease pH
Table 4.22 Utilization of Lime as coagulant in CFS process for WW4 Parameter
FeCl3Dose (mg/L)
Units 0
10
25
50
100
250
400
COD
mg/L
1107
482
507
683
469
457
463
TS
mg/L
1164
1900
1880
1750
1888
1812
1876
Turbidity
JTU
380
0
0
0
0
0
0
SS
mg/L
120
-
-
-
-
40
-
Oil & Grease
mg/L
314
-
-
-
-
6
-
-
12
pH
11,56 11,64 11,68 11,76 12,01 12,10
4.1.2. Use of Starch and Kaolin as Flocculants in CFS Process During these studies, starch and kaolin were used as flocculants, and thus they were added to the beakers in flocculation stage. Alum, lime and FeCl3 were used as coagulants and optimum doses of these chemicals were used from the experiments carried out previous stage. As an alternatively, polyelectrolytes were experienced in order to compare the performance of starch and kaolin as flocculants. Polyelectrolytes used in the
63
experiments were taken from the treatment plants of examined corrugated box factories in the thesis. In the previous stages, optimum dosages were determined as 250mg/l, 50mg/l and 10mg/l for alum, FeCl3 and lime, respectively for WW1, WW2, WW3 and WW4. Throughout the experiments, each additive, i.e. starch, kaolin, polyelectrolyte 1 and polyelectrolyte 2 were dosed as flocculant and their performance on treatment were investigated. During the studies, flocculant doses were maintained as 1 to 10 mg/l. The results regarding WW1 are presented in Tables form 4.23 to 4.25.
64
Table 4.23 The results of CFS experiments for WW1 (Coagulant: alum, Optimum dose: 250 mg/l)
Color (CU*)
SS (mg/L)
Oil & Grease (mg/L)
pH
40
144
7,01
1420
0
-
-
-
5,97
450
1408
0
-
70
62,5
5,93
10
784
1444
0
-
-
-
5,94
0
839
1076
65
195
110
40
5,51
2
378
698
5
13
-
-
5,71
4
319
668
0
13
-
-
5,75
8
279
608
5
18
80
24
5,81
0
1513 1688
165
-
40
144
7,01
5
597
1524
0
-
-
-
5,93
8
557
1540
0
-
-
-
5,97
10
370
1572
0
-
130
77,5
6,08
0
839
1076
65
195
110
40
5,51
2
279
636
25
85
50
28
5,76
4
299
716
13
20
-
-
5,79
8
299
684
2
23
-
-
5,81
TS (mg/L)
-
COD (mg/L)
165
Dose (mg/L)
Turbidity (JTU)
Poly.2
Poly.1
Kaolin
Starch
Flocculants
Parameters
0
1513 1688
5
504
8
65
Table 4.24 The results of CFS experiments for WW1 (Coagulant: Fe3Cl, Optimum dose: 50 mg/l)
Color (CU*)
SS (mg/L)
Oil &Grease (mg/L)
pH
165
-
40
144
7,01
4
435
7424
450
-
-
-
2,40
8
415
7268
480
-
300
98
2,37
10
435
7368
470
-
-
-
2,33
0
839
1076
65
195
110
40
5,51
2
479
5484
210
1900
-
-
1,73
4
388
5172
70
1950
45
18
1,73
8
606
5364
100
1200
-
-
1,73
0
1513 1320
165
-
40
144
7,01
4
415
7520
490
-
360
20
2,31
8
1476 7632
490
-
-
-
2,31
10
475
7172
500
-
-
-
2,33
0
839
1076
65
195
110
40
5,51
2
429
5372
180
1600
37
7
1,78
4
509
5084
120
1750
-
-
1,80
8
589
5740
170
1500
-
-
1,81
TS (mg/L)
1513 1320
COD (mg/L)
0
Doses mg/L)
Turbidity (JTU)
Poly.2
Poly.1
Kaolin
Starch
Flocculants
Parameters
66
Table 4.25 The results of CFS experiments for WW1 (Coagulant: lime, Optimum dose: 10 mg/l)
Color (CU*)
SS (mg/L)
Oil &Grease (mg/L)
pH
40
144
7,01-11,18
1764
0
-
-
-
11,09
557
1764
0
-
30
50
11,08
10
597
1728
0
-
-
-
11,06
0
839
1076
65
195
110
40
5,51-11,22
2
365
460
11
52
-
-
11,03
4
338
428
12
48
20
10
10,95
8
352
600
14
60
-
-
11,96
0
1513 1688
165
-
40
144
7,01-11,18
4
464
1608
0
-
-
-
11,10
8
610
1704
0
-
-
-
10,95
10
437
1684
0
-
40
77
10,90
0
839
1076
65
195
110
40
5,51-11,22
2
564
388
18
65
-
-
11,99
4
378
340
18
75
-
-
11,93
8
345
820
19
63
90
12
11,01
TS (mg/L)
-
COD (mg/L)
165
Doses mg/L)
Turbidity (JTU)
Poly.2
Poly.1
Kaolin
Starch
Flocculants
Parameters
0
1513 1688
4
850
8
Optimum doses were determined as 400mg/l, 50mg/l and 400mg/l for alum, FeCl3 and lime, respectively for WW2. During the studies, flocculant doses, i.e. starch, kaolin, polyelectrolyte 1 and polyelectrolyte 2 were between 1 - 10 mg/l. The results regarding WW2 are presented in Tables from 4.26 to 4.28.
67
Table 4.26 The results of CFS experiments for WW2 (Coagulant: alum, Optimum dose: 400 mg/l)
Oil &Grease (mg/L)
pH
Sludge Volume (ml/L) -
-
-
6,94
135
3600
400
266
6,96
135
3400
-
-
6,98
135
56875
6064
50400
2
3463
8461
1100
3100
4
3303
7376
1550
8
3356
8988
1300
0
41575 18456 170000 352500 24000 11000 7,37
-
2
1857
8356
80800
184000
4
1824
8462
70000
184000 48000
8
1924
8204
79200
176000
0
56875
6064
50400
104000 10000
2
7530
8796
1500
3450
4
4855
6648
1050
8
5978
5376
1350
0
41575 18456 170000 352500 24000 11000 7,37
-
2
2056
8564
76000
184000
-
-
6,98
-
4
1990
9660
80000
188000
-
-
6,98
-
8
1824
9564
90000
204000 28000
1100
6,96
-
SS (mg/L)
0
Color (CU*)
Turbidity (JTU)
7,30
TS (mg/L)
Doses mg/L)
5900
COD (mg/L)
Poly.2
Poly.1
Kaolin
Starch
Flocculants
Parameters
104000 10000
-
-
7,02
-
1000
6,99
-
-
6,97
-
5900
7,30
-
-
-
6,86
100
2900
340
90
6,86
250
3400
-
-
6,88
400
-
68
Table 4.27 The results of CFS experiments for WW2 (Coagulant: Fe3Cl, Optimum dose: 50 mg/l)
Poly.2
Poly.1
Kaolin
Oil &Grease (mg/L)
pH
Sludge Volume (ml/L) -
20
170
2,28
800
84000
-
-
2,21
600
108000
-
-
2,28
640
56875
6064
50400
2
2093
4427
120000 268000
4
2194
4072
36000
8
2545
3496
36000
0
41575 18456 170000 352500 24000 11000 7,37
SS (mg/L)
0
Color (CU*)
Turbidity (JTU)
7,30
TS (mg/L)
Doses mg/L)
5900
COD (mg/L)
Starch
Flocculants
Parameters
104000 10000
-
2
835
42368 102000 240000
-
-
1,73
-
4
587
21600 104000 232000
4000
1600
1,74
-
8
504
19560 108000 248000
-
-
1,74
-
0
56875
6064
50400
104000 10000
5900
7,30
-
2
2307
3560
19000
56000
80
30
2,20
540
4
3247
3528
58000
132000
-
-
2,26
600
8
2294
3016
100000 172000
-
-
2,25
660
0
41575 18456 170000 352500 24000 11000 7,37
2
670
13984 104000 228000 20000
4
2243
18556 100000 224000
8
2988
18676
90000
208000
-
1300
1,77
-
-
-
1,76
-
-
-
1,75
-
69
Table 4.28 The results of CFS experiments for WW2 (Coagulant: lime, Optimum dose: 400 mg/l)
TS (mg/L)
Turbidity (JTU)
Color (CU*)
SS (mg/L)
Oil &Grease (mg/L)
pH
0
56875
6064
50400
104000
10000
5900
7,30-8,23
2
24557 13192 141670
341670
-
-
8,66
4
12267 11692 110000
260000
5000
40
8,77
8
17127 13960 600000
850000
-
-
8,76
0
41575 18456 170000
352500
24000 11000 7,37-11,82
2
11951
7656
168000
300000
8000
5000
11,37
4
14601
7712
170000
300000
-
-
11,75
8
16257
7113
164000
296000
-
-
11,93
0
56875
6064
50400
104000
10000
5900
7,30-8,23
2
10261
5444
462500
925000
9200
190
8,60
4
13521
6152
450000
887500
-
-
8,70
8
13855 13320 625000 1000000
-
-
8,78
0
41575 18456 170000
352500
2
18906
8010
150000
284000
-
-
11,68
4
18606
8820
170000
300000
-
-
11,77
8
15264
8615
152000
280000
20000
4800
11,71
Doses mg/L)
COD (mg/L)
Poly.2
Poly.1
Kaolin
Starch
Flocculants
Parameters
24000 11000 7,37-11,82
Optimum doses used for WW3 are 25mg/l, 50mg/l and 400mg/l for alum, FeCl3 and lime respectively. During the experiments, each flocculant were dosed between 1 to 10 mg/l into the beakers and then the removal efficiencies were investigated for every parameter. The results are presented in the Tables from 4.29 to 4.31.
70
Table 4.29 The results of CFS experiments for WW3 (Coagulant: alum, Optimum dose: 25 mg/l)
Poly.2
Poly.1
Kaolin
Starch
pH
Oil &Grease (mg/L)
SS (mg/L)
Color (CU*)
Turbidity (JTU)
TS (mg/L)
COD (mg/L)
Doses mg/L)
Flocculants
Parameters
0
70000 6976 83333
-
7880 6380 7,75
2
22512 7200 62500
-
6
20752 7328 77500
-
8
21884 7420 86250
-
-
-
7,73
0
1103
2336
260
560
480
128
6,54
2
825
1884
10
30
-
-
7,69
4
762
1900
16
45
240
12
7,71
8
792
924
25
45
-
-
7,68
-
-
7,71
3960 3480 7,75
0
70000 6976 83333
-
7880 6380 7,75
2
20690 6990 87000
-
6
19000 7064 87500
-
8
22010 7110 82500
-
-
-
7,78
0
1103
2336
260
560
480
128
6,54
2
805
2060
19
55
-
-
7,73
4
759
1964
23
75
170
58
7,73
8
792
2016
32
70
-
-
7,74
-
-
7,74
5320 2380 7,66
71
Table 4.30 The results of CFS experiments for WW3 (Coagulant: FeCl3, Optimum dose: 200mg/l)
Sludge Volume (ml/L)
70000
6976
83333
-
2
11390 116696
2500
-
6
16624 116572
3600
680
8
25689 105836
2600
-
-
0,72
700
0
1103
2336
260
560
480
128
6,54
-
2
896
14740
650
3050
-
-
1,10
-
4
564
5172
700
3100
310
14
1,11
-
8
780
15188
600
3050
-
-
1,11
-
0
70000
6976
83333
-
7880 6380 7,75
-
2
14864 108932
3800
-
520
784
0,71
720
6
13482 126560
4600
-
-
-
0,65
660
8
17630 126688
3400
-
-
-
0,69
640
0
1103
2336
260
560
480
128
6,54
-
2
1090
14684
750
1700
-
-
1,10
-
4
813
14616
875
3400
300
26
1,12
-
8
1061
14824
875
3250
-
-
1,13
-
pH
Color (CU*)
Oil &Grease (mg/L)
Turbidity (JTU)
0
SS (mg/L)
TS (mg/L)
Doses mg/L)
COD (mg/L)
Poly.2
Poly.1
Kaolin
Starch
Flocculants
Parameters
7880 6380 7,75 -
-
0,67
650
1218 0,69
680
72
Table 4.31 The results of CFS experiments for WW3 (Coagulant: lime, Optimum dose: 50mg/l)
Poly.2
Poly.1
Oil &Grease (mg/L)
-
2
32082 5093 108000
-
6
30196 5372 106000
-
8
30574 5581 118000
-
-
-
11,89
0
1103
2336
260
560
480
128
6,54-11,73
2
597
2216
22
70
220
88
10,43
4
631
2008
38
85
-
-
10,49
8
962
2096
22
95
-
-
10,60
pH
83333
SS (mg/L)
70000 6976
TS (mg/L)
0
COD (mg/L)
Color (CU*)
Doses mg/L)
Turbidity (JTU)
Kaolin
Starch
Flocculants
Parameters
7880 6380 7,75-11,00 -
-
1560 5200
11,50 11,72
0
70000 6976
83333
-
7880 6380 7,75-11,00
2
33212 5232
70000
-
6
28940 4883
65000
-
8
30070 5372
89000
-
-
-
11,16
0
1103
2336
260
560
480
128
6,54-11,73
2
631
2298
28
98
-
-
10,49
4
532
2036
35
100
260
76
10,38
8
564
2103
24
98
-
-
10,43
-
-
1880 6180
11,22 11,18
During the previous work, optimum doses were determined as 400mg/l, 25mg/l and 400mg/l, for alum, FeCl3 and lime respectively. Similar flocculant doses were applied in this step and the treatment performance of the flocculants was examined. The results of this study is presented in Tables from 4.33 to 4,35.
73
Table 4.32 The results of CFS experiments for WW4 (Coagulant: alum, Optimum dose: 400mg/l)
Poly.2
Poly.1
Color (CU*)
SS (mg/L)
Oil &Grease (mg/L)
pH
380
-
120
512
7,61
4
1036
872
110
-
-
-
6,32
8
1036
833
10
-
-
-
6,37
10
703
668
350
-
127
314
6,43
0
157
692
85
250
70
44
7,07
2
36
556
5
30
-
-
6,48
4
29
460
0
35
21
34
6,47
8
49
464
0
25
-
-
6,45
TS (mg/L)
1107 1164
COD (mg/L)
0
Doses mg/L)
Turbidity (JTU)
Kaolin
Starch
Flocculants
Parameters
0
1107 1164
380
-
120
512
7,61
4
906
832
25
-
33
25
6,35
8
993
928
30
-
-
-
6,34
10
1050 1012
0
-
-
-
6,80
0
157
692
85
250
70
44
7,07
2
59
536
0
40
-
-
6,46
4
39
500
0
35
20
39
6,49
8
53
608
0
50
-
-
6,60
74
Table 4.33 The results of CFS experiments for WW4 (Coagulant: FeCl3, Optimum dose: 25mg/l)
Poly.2
Poly.1
Color (CU*)
SS (mg/L)
Oil &Grease (mg/L)
pH
90
220
240
122
7,42
2
4129 5124
280
900
-
-
1,97
4
3660 5200
340
920
-
-
1,95
8
3527 5440
290
880
20
40
1,91
0
157
592
115
290
220
102
7,19
2
58
2948 2500
320
-
-
2,04
4
45
2980 2900
580
150
76
2,02
8
65
2928 3100
450
-
-
2,03
TS (mg/L)
5107 1060
COD (mg/L)
0
Doses mg/L)
Turbidity (JTU)
Kaolin
Starch
Flocculants
Parameters
0
5107 1060
90
220
240
122
7,42
2
3928 5524
300
910
-
-
1,89
4
3594 4984
280
890
-
-
1,96
8
3527 4860
270
880
50
100
1,96
0
157
592
115
290
220
102
7,19
2
92
2896 2950
530
-
-
2,04
4
58
2940 2180
350
170
94
2,06
8
58
2952 3100
600
-
-
2,05
75
Table 4.34 The results of CFS experiments for WW4 (Coagulant: lime, Optimum dose: 400mg/l)
Color (CU*)
SS (mg/L)
Oil &Grease (mg/L)
pH
380
-
120
314
7,61-11,00
4
1023 1648
70
-
-
-
11,13
8
753
1644
80
-
116
113
11,11
10
759
1628
75
-
-
-
11,22
0
157
692
85
250
70
44
7,07-10,90
2
59
616
5
0
-
-
11,25
4
52
628
0
70
40
21
11,25
8
56
608
15
45
-
-
11,28
0
1107 1164
380
-
120
314
7,61-11,00
4
776
1632
78
-
173
75
11,21
8
976
1680
85
-
-
-
11,61
10
1003 1664
89
-
-
-
11,08
0
157
692
85
250
70
44
7,07-10,90
2
89
612
20
85
-
-
11,28
4
62
608
12
70
60
23
11,32
8
66
628
12
40
-
-
11,35
TS (mg/L)
1107 1164
COD (mg/L)
0
Doses mg/L)
Turbidity (JTU)
Poly.2
Poly.1
Kaolin
Starch
Flocculants
Parameters
76
4.2. Flotation
4.2.1. Flotation without Any Chemicals In the experimental studies, flotation was applied to remove the pollutants from wastewater samples. Treatment performance of flotation process was investigated for each wastewater and the results of experiments are given in Table 4.353.
Table 4.35 The results of plain flotation for each wastewater
COD
TS
(mg/L) (mg/L)
Turbidity
Color
(JTU)
CU
SS
Oil&
pH
(mg/L) Grease
Inf.
1513
1688
165
-
40
144
7,01
Eff.
375
1456
5
-
30
60
7,80
Inf.
56875
6064
50400
104000
10000
5900
7,30
Eff.
6597
4052
36000
104000
300
610
7,72
Inf.
78000
4672
68000
-
16000
2000
7,65
Eff.
22000
3551
30000
-
2400
680
8,28
Inf.
(mg/L)
1367
1060
90
220
240
350
7,42
Eff.
WW4
WW3
WW2
WW1
Wastewaters
Parameters
77
1036
85
240
310
12
7,93
77
4.2.2. Flotation with Chemicals Following to the experiments relating to the plain flotation, the effect of the chemical addition to the performance of flotation operation was investigated in the next step. Starch, kaolin, alum, ferric chloride and lime were used as chemicals. Optimum doses of each chemical, which were determined before, were added to the flotation unit. Experimental results of flotation with chemicals, i.e. starch, kaolin, alum, FeCl3, and lime is given in Tables from 4.36 to 4.40 including each wastewater.
Table 4.36 Experimental results of flotation process for starch
COD
TS
(mg/L) (mg/L)
Turbidity
Color
(JTU)
CU
SS
Oil&
pH
(mg/L) Grease
Inf.
1513
1688
165
-
40
144
7,01
Eff.
1246
1676
90
-
120
15
8,21
Inf.
15434
17812
200000
480000
20400
2060
7,62
Eff.
15213
6688
71500
109850
23400
1955
7,72
Inf.
78000
4672
68000
-
16000
2000
7,65
Eff.
8000
3536
31200
-
3000
1580
8,40
Inf.
(mg/L)
324
564
115
290
90
102
7,19
Eff.
WW4
WW3
WW2
WW1
Wastewaters
Parameters
126
624
118
320
210
46
8,19
78
Table 4.37 Experimental results of flotation process for kaolin
COD
TS
(mg/L) (mg/L)
Turbidity
Color
(JTU)
CU
SS
Oil&
pH
(mg/L) Grease
Inf.
839
2956
65
195
110
40
5,51
Eff.
500
872
215
475
160
36
7,87
Inf.
41575
11884
170000
352500
27500
11000
7,37
Eff.
2574
6532
90000
220000 140000
8000
7,64
Inf.
78000
4672
68000
-
16000
2000
7,65
Eff.
12500
2589
45000
-
22000
1500
8,01
Inf.
(mg/L)
324
592
115
290
220
102
7,19
Eff.
WW4
WW3
WW2
WW1
Wastewaters
Parameters
110
528
45
145
50
13
8,20
79
Table 4.38 Experimental results of flotation process for alum
COD
TS
(mg/L) (mg/L)
Turbidity
Color
(JTU)
CU
SS
Oil&
pH
(mg/L) Grease
Inf.
1513
1688
165
-
40
144
7,01
Eff.
1410
1688
118
-
188
92,5
7,73
Inf.
15434
17812
200000
480000
20400
2060
7,62
Eff.
11017
12160
210000
258000
15000
1364
7,30
Inf.
78000
4832
63000
-
10000
1200
7,59
Eff.
14400
4900
30000
-
2400
220
8,45
Inf.
(mg/L)
324
564
115
290
90
102
7,19
Eff.
WW4
WW3
WW2
WW1
Wastewaters
Parameters
63
596
80
240
350
64
7,71
80
Table 4.39 Experimental results of flotation process for FeCl3
COD
TS
(mg/L) (mg/L)
Turbidity
Color
(JTU)
CU
SS
Oil&
pH
(mg/L) Grease
Inf.
1513
1688
165
-
40
144
7,01
Eff.
555
5700
350
-
108
42,5
2,44
Inf.
15434
17812
200000
480000
20400
2060
7,62
Eff.
5609
16684
130000
310000
15000
1818
3,39
Inf.
76000
8320
112000
-
6800
2020
7,54
Eff.
7640
68840
3600
-
1360
101
0,77
Inf.
(mg/L)
324
564
115
290
90
102
7,19
Eff.
WW4
WW3
WW2
WW1
Wastewaters
Parameters
300
3216
600
940
330
26
2,11
81
Table 4.40 Experimental results of flotation process for lime
COD
TS
(mg/L) (mg/L)
Turbidity
Color
(JTU)
CU
SS
Oil&
pH
(mg/L) Grease
Inf.
1513
1688
165
-
40
144
11,40
Eff.
979
2008
25
-
200
77,5
10,95
Inf.
15434
17812
200000
480000
20400
2060
8,68
Eff.
12047
15512
215000
395000
15000
2009
8,18
Inf.
76000
8320
112000
-
6800
2020
8,54
Eff.
37600
9116
89600
-
3000
1607
9,85
Inf.
(mg/L)
324
564
115
290
90
102
11,04
Eff.
WW4
WW3
WW2
WW1
Wastewaters
Parameters
73
1012
250
540
710
78
11,55
4.3. Sedimentation
4.3.1. Plain Sedimentation (PS) Throughout the laboratory studies, the treatment performance of sedimentation process was also experienced for each wastewater composition. Treatment performance was evaluated for the parameters of Solid Matter, Turbidity, Color, Oil and grease as well as COD parameter. The summary of those measurements is presented in Table 4.41.
82
Table 4.41 Experimental results of primary sedimentation unit for each wastewater
COD
TS
Turbidity
Color
(JTU)
CU
(mg/L) (mg/L)
SS
Oil&
pH
(mg/L) Grease
Inf.
3360
1072
5
60
140
84
7,57
Eff.
1149
1080
1
25
180
80
8,03
Inf.
15434
17812
200000
480000
20400
2060
7,62
Eff.
11333
17316
232500
600000
15000
1600
7,74
Inf.
78000
4672
68000
-
16000
2000
7,65
Eff.
64000
4376
30000
-
3640
1800
7,57
Inf.
(mg/L)
1367
1060
90
220
240
350
7,42
Eff.
WW4
WW3
WW2
WW1
Wastewaters
Parameters
1260
1036
75
180
270
46
7,02
4.3.2. Chemical Precipitation During the experimental studies, better settlement of particulates has been observed at lower pH conditions for both WW2 and WW3. Therefore, in order to examine the effect of various pH conditions on treatment performance, HCL was added to wastewater of WW2 and WW3. The results of those investigations are presented in Table 4.42.
83
Table 4.42 The results of the chemical precipitation studies with HCl addition Parameter
Unit
WW2
WW3
Effluent
Influent
Influent
pH
