1. Performance of the deep bed filter
at its loading with particles and microorganisms
Leon Gradon and Ewa Sztuk
phone:
address: Warynskiego 1, Warsaw, PL
Separation Techniques, September 2016, Valencia

2. Contents Introduction Principles of deep-bed filtration
Mechanisms of particle and bacteria deposition
Filter loading and biofouling
Formation of fibrous filters with the melt-blown technique
Testing of filters
Conclusions
Separation Techniques, September 2016, Valencia

3. Introduction – World Trends
world population growth
growing demand for water
climate
changes
water reclamation
and reuse *
Separation Techniques, September 2016, Valencia

4. Introduction – World Trends*
Separation Techniques, September 2016, Valencia

5. Introduction – depth filtration
untreated water
AIM
maximalize the time of filtration with high filtration efficiency
and low pressure drop
CHALLENGES
1. Resuspension of deposit
2. Removal of nanoobjects
3. Biofouling
agglomerate break
relocation
filtration efficiency
pressure drop
time
filtered water
Separation Techniques, September 2016, Valencia

6. Principle of deep-bed filtration
α(z), df(z) c0 ck z
Separation Techniques, September 2016, Valencia

7. Mechanisms of particle deposition
Separation Techniques, September 2016, Valencia

8. Composite filters: testing
ζ [mV]
Polypropylene
-40
Zinc oxide -6
Silver
-33
Halloysite
-30
Hematite
-20
Arizona Test Dust
Henry C. et al. (2013) Langmuir, 29 (45),
Separation Techniques, September 2016, Valencia

9. Performance of filter during loadingB
SEM images of a fibrous filter tested on solid particles.
CLSM images of a fibrous filter tested on natural river water. A – outer layer, B – 1 mm deep, C – 5 mm deep.
Separation Techniques, September 2016, Valencia

10. Formation of fibrous deep-bed filter
1 – polymer container
2 – extrusion screw
3 – electric heater
4 – die
5 – compressor and air heater
6 – fiber collector
Separation Techniques, September 2016, Valencia

11. Single fiber formation
Separation Techniques, September 2016, Valencia

12. Newton’s constitutive equation:
continuity equation:
equation of motion:
Newton’s constitutive equation:
energy balance equation:
Separation Techniques, September 2016, Valencia

13. Fiber axial stretching force
Separation Techniques, September 2016, Valencia

14. Distribution of process parameters inside the fiber
Separation Techniques, September 2016, Valencia

15. Polymer molecules orientation
Separation Techniques, September 2016, Valencia

16. Formation of fibrous deep-bed filter
Separation Techniques, September 2016, Valencia

17. Mixed – fiber filters: testing
Theory
nanofiber
microfiber
Przekop R., Gradon L. (2008) Aerosol Science and Technology, 42,
Experiment
nanofibers
microfiber
Separation Techniques, September 2016, Valencia

18. Performance of filter during loading
Separation Techniques, September 2016, Valencia

19. Performance of filter during loading
Separation Techniques, September 2016, Valencia

20. Formation of fibrous deep-bed filter
1 – polymer container
2 – nanoparticles container
3 – twin-screw extrusion cylinder
4 – die
5 – composite monofilament
6 – water bath
7 – knife system
8 – composite granulate
Separation Techniques, September 2016, Valencia

21. Filter modifications with nanoparticles
Separation Techniques, September 2016, Valencia

22. Filter modifications with nanorods1) 2)
Separation Techniques, September 2016, Valencia

23. Filter modifications with nanoparticles
Antibacterial and bacteriostatic plate test: A - on E. coli on differentiating medium incubated for 24 h at 37°C, B – on B. subtilis on LB medium incubated for 24 h at 37°C. PP – pure polypropylene. 1, 2, 3, 4 – layers of modified fabric starting from the filter’s inlet.
Separation Techniques, September 2016, Valencia

24. Composite filters: testing
Changes of optical density of test cultures induced by the presence of particular filters
Separation Techniques, September 2016, Valencia

25. Performance of filter during loading
Separation Techniques, September 2016, Valencia

26. Biofouling
Separation Techniques, September 2016, Valencia

27. Biofouling
Separation Techniques, September 2016, Valencia

28. Conclusions
Deep-bed filters are efficient tools for removal of submicron particles and microorganisms form water.
Filter loading with abiotic particles and colonization of microorganisms within the filter significantly reduce the filter life-time.
Melt-blown is a useful technique for designing of deep-bed structures for uniform distribution of deposits in the filter volume.
Composite fibers consisting Ag/ZnO nanoparticles on the surface significantly reduce biofouling effect during collection of microorganisms in filter.
Separation Techniques, September 2016, Valencia

29. Thank you for your attention
Separation Techniques, September 2016, Valencia