The document discusses alternative dredging methods using mud conditioning to maintain navigable depths. It presents a case study from Emden where mud conditioning techniques kept sediments navigable, reducing maintenance dredging needs. The key techniques discussed are: 1. Artificially liquefying consolidated mud through controlled shear stress to maintain fluid mud layers. 2. The "KSN" or "Keep Sediments Navigable" method which periodically mixes mud layers to prevent consolidation without removing material. 3. Trials in Rotterdam demonstrated mud conditioning relocated sediments and increased navigable depths without dredging.

1. - - - - Alternative Dredging „Mud Conditioning“ Case Study Emden Surveying Problems and the Physical Behaviour of Fluid Mud Offer new Dredging Strategies Workshop Antwerpen, 08.12.2010 Norbert Greiser GREISER AND PARTNER Dredging Applications

2. Agenda - - Determination and Maintaining Nautical Depth 1. Surveying Problems 2. Additional Measuring Technology 3. Fluid Mud 4. Mud Conditioning Aussenhafen Emden (open basin to River Ems) GREISER AND PARTNER Dredging Applications

3. 1. Surveying Problems - - Proof of Nautical Depth by Echosounding Which echosounding layer represents the nautical depth ? GREISER AND PARTNER Dredging Applications

4. 1. Surveying Problems - - Proof of Nautical Depth by Echosounding GREISER AND PARTNER Dredging Applications

5. 1. Surveying Problems - - Proof of Nautical Depth by Echosounding GREISER AND PARTNER Dredging Applications

6. 1. Surveying Problems - - Multi Frequency-Echosounding is needed for Sediment Layer Detection 210 kHz 33 kHz Still open Question: Layer Consistency? ? ? GREISER AND PARTNER Dredging Applications

7. Agenda - - Determination of Nautical Depth 1. Surveying Problems 2. Additional Measuring Technology 3. Fluid Mud 4. Mud Conditioning Density / Stiffness Limits for Safe Navigation ? GREISER AND PARTNER Dredging Applications

8. 2. Additional Measuring Technology - - Vertical Profiling Probes are Required Vertical Extension of Navigable Layer(s) ? Determination of Nautical Depth GREISER AND PARTNER Dredging Applications

9. 2. Additional Measuring Technology - - Vertical Profiling Example: Nautical Depth Extension 4,5 m  8,0 m GREISER AND PARTNER Dredging Applications

10. Agenda - - 1. Surveying Problems 2. Additional Measuring Technology 3. Fluid Mud 4. Mud Conditioning Origin and Stability of Fluid Mud GREISER AND PARTNER Dredging Applications

11. - - 3. Fluid Mud Progressive Aggregation SPM from River Weser Fluorescence Dye FITC Origin: Clay-Microbes Assemblages /Stability: Sticky EPS GREISER AND PARTNER Dredging Applications

12. - - 3. Fluid Mud SEM Preparation Acroleine fixed EPS SPM from River Ems Origin: Clay-Microbes Assemblages /Stability: Sticky EPS GREISER AND PARTNER Dredging Applications

13. - - 3. Fluid Mud SEM - Preparation Bakteria Cell with EPS - Filaments SPM from River Elbe Origin: Clay-Microbes Assemblages /Stability: Sticky EPS GREISER AND PARTNER Dredging Applications

14. Agenda - - 1. Surveying Problems 2. Additional Measuring Technology 3. Fluid Mud 4. Mud Conditioning Artificial Liquefaction Maintaining Nautical Depth GREISER AND PARTNER Dredging Applications

15. 4. Sediment Conditioning Artificial Liquefaction Maintaining Nautical Depth by Shear Stress Controlled Liquefaction GREISER AND PARTNER Dredging Applications

16. 4. Sediment Conditioning KSN - Keep Sediments Navigable – „Emden Method“ GREISER AND PARTNER Dredging Applications Navigable Sediment Layer Not Navigable Consolidated Silt

17. 4. Sediment Conditioning Since 1990 a new iteration, “ Active Nautical Depth”, objective to keep fluid mud entrained in situ by occasional mixing without ever carrying any material away. Need for “mixing” creates the “Active” component of keeping mud navigable. Artificial Liquefaction Maintaining Nautical Depth by KSN GREISER AND PARTNER Dredging Applications

18. 4. Sediment Conditioning Throughout 5 years, maintenance dredging needs at Emden reduced to zero, staff from 110 to 4, and costs from € 12.5 million to €2 million/yr. Formerly maintenance dredging and disposal need was 4 million m ³/yr. Important aim is to maintain a “neutral” sediment budget (neither long-term gain or loss of mud). “ Conditioning”, ie. not just re-fluidising mud but also re-oxygenating it in the open hopper. Artificial Liquefaction Maintaining Nautical Depth by KSN GREISER AND PARTNER Dredging Applications

19. Agenda - - 1. Surveying Problems 2. Additional Measuring Technology 3. Fluid Mud 4. Mud Conditioning Thanks for Your Attention ! Maintaining Nautical Depth by KSN GREISER AND PARTNER Dredging Applications

20. - - 4. Sediment Conditioning KSN - Keep Sediments Navigable • „ Ketchup-Principle“ (Rheology) GREISER AND PARTNER Dredging Applications

21. - - 4. Sediment Conditioning • Navigable Fluid Mud (Rheogramme) GREISER AND PARTNER Dredging Applications

22. - - 4. Sediment Conditioning • Application for Maintenance Dredging KSN - Keep Sediments Navigable Suspended Matter Fluid Mud Fluid Mud Consolidated Mud GREISER AND PARTNER Dredging Applications

23. - - 4. Sediment Conditioning Port of Rotterdam Conditioning Trials Botlek Harbour (2x) Petroleumhaven 2e GREISER AND PARTNER Dredging Applications

24. - - 4. Sediment Conditioning Port of Rotterdam Conditioning Trials Botlek Harbour GREISER AND PARTNER Dredging Applications

25. - - 4. Sediment Conditioning Port of Rotterdam Conditioning Trials Conditioning Area 183.315 m 2 4 3 3 7 0 GREISER AND PARTNER Dredging Applications

26. - - 4. Sediment Conditioning 400 kHz Multibeam Chart Dredging Tracks before Conditioning GREISER AND PARTNER Dredging Applications

27. - - 4. Sediment Conditioning 400 kHz Multibeam Chart Dredging Tracks after Conditioning Main Sedimentation Area of the Relocated Silt GREISER AND PARTNER Dredging Applications

28. - - 4. Sediment Conditioning Dual Frequency Pre- and Post-Dredging Charts GREISER AND PARTNER Dredging Applications Location of the Profile Left end Right end

29. - - 4. Sediment Conditioning Dual Frequency Pre- and Post -Dredging Charts GREISER AND PARTNER Dredging Applications Depth (m) 210 kc-Layer 15 kc-Layer Distance (m) 0.7 m

30. - - 4. Sediment Conditioning Dual Frequency Pre- and Post-Dredging Charts GREISER AND PARTNER Dredging Applications Depth (m) 210 kc-Layer 15 kc-Layer Distance (m) 1.5 m

31. - - 4. Sediment Conditioning Nautical Depth Profiling GREISER AND PARTNER Dredging Applications Clear Shift to Lower Attenuation Values Pre- Profile Post- Profile Navigable Not Navigable 500 kHz 1 MHz 2 MHz

32. - - 4. Sediment Conditioning 2e Petroleumhaven GREISER AND PARTNER Dredging Applications

33. - - 4. Sediment Conditioning 2e Petroleumhaven GREISER AND PARTNER Dredging Applications

34. - - 4. Sediment Conditioning Starting with Bed Levelling GREISER AND PARTNER Dredging Applications

35. - - 4. Sediment Conditioning Dumping and Conditioning of about 40.000 m 3 of Silt South Part GREISER AND PARTNER Dredging Applications

36. - - 4. Sediment Conditioning Sediment Core after Conditioning GREISER AND PARTNER Dredging Applications Rotterdam Petroleumhaven 2e Fluidised Mud Solid Bottom Material Weak Mud