1. 1 Challenge the future Cake layer characteristics in long time ceramic MF filtration for surface water treatment Mingyang Li Master defence presentation

2. 2 Challenge the future Contents Background Research objective Experiments Results Conclusions Recommendations & Futre work

3. 3 Challenge the future Background Good & stable water quality Low energy use (low pressurized) Easily operated Ceramic microfiltration Microfiltration

4. 4 Challenge the future Background Compared to conventional polymeric membranes: Low fouling tendency Higher permeability Resistance to pH, heat and chemical conditions Price becoming cheaper Ceramic membranes

5. 5 Challenge the future Background Membrane Fouling Alternative solutions: Pretreatment used: Pre-coagulation Solid wastes Frequent backwash used Low recovery High maintenance cost High energy consumption Ceramic Microfiltration problem

6. 6 Challenge the future Research objective Increase the filtration time in ceramic microfiltration with in-line coagulation Highlights: In-line coagulation, no flocs removed Long filtration time, TMP increase controlled Practical Support: MBR installations Sludge layer on surface effective fouling control

7. 7 Challenge the future Experiments Cake layer importance Important cause for TMP increase (constant flux) 80% resistance percentage in total resistance (PACl) Controlled by coagulation mechanisms (pH, dosage)

8. 8 Challenge the future Experiments Coagulation mechanisms Figure 1 Coagulation zones Three zones divided by pH and dosage Cake layer formations membrane performances

9. 9 Challenge the future Experiments Flow scheme Figure 2 Experimental scheme pH=4, 6 and 8,Dosage=8 and 16mg/L Flux 60 L/(m2*h)

10. 10 Challenge the future Experiments Experimental setup

11. 11 Challenge the future Experiments Experimental setup

12. 12 Challenge the future Results Figure 3 TMP curve with BW and without BW Recorded by data logger (Dataq, DI710) Constant flux 60 (L/m2*h) Slow TMP increase in cake filtration TMP

13. 13 Challenge the future Results Figure 4 TMP curve under coagulant dosage of 8 and 16 mg/L In cake filtration, TMP increased differently pH=4 leads to slow TMP increase (Restabilization coagulation) pH=6 leads to rapid TMP increase (Adsorption coagulation) TMP

14. 14 Challenge the future Results Resistance

15. 15 Challenge the future Results Table 1 Resistance components Rc is the largest resistance component pH=4 leads to the smallest resistance pH=6 leads to largest resistance Resistance R (10 12 m -1 )Fe 3+ =8mg/LFe 3+ =16mg/L RmRpRcRmRpRc pH=40.48 1.370.540.421.61 pH=60.540.723.70.480.783.15 pH=80.540.602.150.540.421.91

16. 16 Challenge the future Results Cake layer density & water content

17. 17 Challenge the future Results Table 2 Cake layer density Table3 Cake layer water content pH=4 leads to smallest density, but largest water content pH=6 leads to largest density, but smallest water content Cake layer density & water content Density (kg/m 3 *10 3 )Fe 3+ =8mg/LFe 3+ =16mg/L pH=41.0251.018 pH=61.0701.083 pH=81.0451.050 Water contentFe 3+ =8mg/LFe 3+ =16mg/L pH=40.9730.967 pH=60.9210.928 pH=80.937

18. 18 Challenge the future Results Cake layer thickness

19. 19 Challenge the future Results Table 4 Cake layer thickness Higher chemical dosage, higher the cake layer pH=4 leads to largest cake thickness, pH=6 leads to the smallest cake thickness Cake layer height Thickness (mm)Fe 3+ =8mg/LFe 3+ =16mg/L pH=40.350.56 pH=60.110.24 pH=80.150.28

20. 20 Challenge the future Results Cake layer thickness

21. 21 Challenge the future Results Table 5 Cake layer particle size pH=4 leads to largest cake particles pH=6 leads to the smallest cake particles Cake layer particle size Fe 3+ =8mg/LFe 3+ =16mg/L pH=40.410.37 pH=60.100.13 pH=80.160.20

22. 22 Challenge the future Results Cake layer compressibility

23. 23 Challenge the future Results Table 6 Cake layer compressibility factor pH=4 leads to large compressibility factor, loose structure pH=6 leads to the small compressibility factor, dense structure Cake layer compressibility Compressibility factorFe 3+ =8mg/LFe 3+ =16mg/L pH=40.570.70 pH=60.330.48 pH=80.520.60

24. 24 Challenge the future Results Table 7 DOC removal efficiency Higher chemical dosing, higher removal efficiency (first stage) DOC remove shows no clear tendency with pH DOC removal Fe 3+ =8mg/LFe 3+ =16mg/L S1S2TotalS1S2Total pH=440%17%58%42%8%50% pH=625%7%32%37%15%52% pH=84%15%20%10%31%41%

25. 25 Challenge the future Conclusions Membrane performance can be controlled by various pre- coagulation zones It is possible to achieve a long filtration time by applying cake filtration Cake layer plays an important role in fouling control process pH=4 leads to loose cake structure, shown as slow TMP increase, low cake layer density, high cake layer water content, thickness, particle size and compressibility pH=6 leads to dense cake structure, shown as rapid TMP increase, high cake layer density, low cake layer water content, thickness, particle size and compressibility DOC remove shows no clear tendency with pH

26. 26 Challenge the future Recommendations & Future work pH=4, Dos=8 is good pre-coagulation condition in ceramic microfiltration More experiments about the explanations between coagulation mechanisms and cake layer structure Mechanism cake layer structure phenomenon More experiments about low chemical, for instance Dos=4mg/L