Lecture Notes: Filtration

Types of Filtration

1. Air Filtration

   • HEPA Filtration
     • HEPA stands for High-efficiency Particulate Air filters.
     • Pore size: 0.3 micrometers or smaller.
     • Previously rare and expensive, now common in household devices like vacuums.
     • Important for filtering microbes in healthcare environments.

2. Liquid Filtration

   • Membrane Filtration
     • Used to remove microbes from liquids, especially heat-sensitive materials.
     • Requires a pore size of 0.2 micrometers or smaller.
     • Smaller pores available (e.g., 0.08 micrometers) can filter out bacteria, viruses, and prions.
     • Useful for sterilizing substances that can't be heated.

Applications of Filtration

• HEPA Filtration

  • Essential in environments where air purity is critical, such as healthcare.

• Membrane Filtration

  • Suitable for heat-sensitive components:
    • Vitamins
    • Antibiotics
    • Vaccines

Challenges with Vaccines

• Vaccines require refrigeration and cannot be heated.
• Cold chain maintenance is crucial but often fails, rendering vaccines ineffective.
  • Some regions lack adequate refrigeration or have unreliable power.
  • Transportation often involves suboptimal cooling methods (e.g., Styrofoam coolers).

Future Directions

• Improving Vaccines
  • Aim for vaccines that do not require refrigeration.
  • This could drastically improve vaccine effectiveness and distribution, especially in resource-limited settings.

Conclusion

• Filtration is a critical method for controlling microbial growth without using heat.
• Two main examples highlighted:
  • HEPA filtration for air.
  • Membrane filtration for liquids.
• Encouragement to consider advancements in vaccine technology to solve refrigeration challenges.