The Technology

  • filtration process based on physical separation;
  • typically, it works without using any chemicals;

  • the membrane is semi-permeable i.e. certain substances or particles can go through the membrane and other substances are caught;

  • which substances can go through or cannot go through is depend on the pore size of the membrane;

  • substances or particles that have diameter bigger than the pore size will be trapped by the membrane, therefore size of the membrane pore is the factor determine what size of particles needs to be filtered;

  • types of membrane filtration based on the pore sizes are:

    • micro-filtration – 0.1 micron
    • ultra-filtration – 0.01 micron
  • other types of membrane filtration are:

    • nano-filtration – 0.001 micron
    • reverse osmosis – less than 0.001 micron, depends on the specific membrane manufacturer
  • however, nanofiltration and reverse osmosis perform impurities separation by diffusion through the membrane and they need higher application of pressure with lower productivity than the other types of membrane.
  • membrane materials known, used for water filtration system are:

    • polyethersulfone (PES)
    • polytetrafluoroethylene (PTFE)
    • cellulose acetate (CA/CTA)

Benefits of Membrane Filtration Technology

  • it can filter wide range of impurities, based on the pore size of membrane,

  • it can be used with combination with adsorbents for filtration of certain harmful chemicals that cannot be filtered by membrane filter alone or it is more cost effective to have larger pore membrane with having adsorbents to trap other chemicals,

  • microfiltration, ultrafiltration, nanofiltration and reverse osmosis have the ability to filter bacteria, parasites, fungi and cysts,

  • it works without using chemicals to kill water borne pathogens,

  • compact design as a large membrane surface is fitted into a small volume.

Limitations of Membrane Filtration Technology

  • clogging of membrane is likely to happen due to its small pore size

  • how serious and how frequent of the membrane to get clog is depends on:

    • the quality of incoming water i.e. tap water or water to be filtered
    • quantity of water usage
    • membrane type i.e. tubular membrane system or plate & frame membrane system
    • membrane materials
    • frequency and duration of flushing
    • frequency and duration of backwash
  • cleaning of membrane using flushing and backwash process need large amount of water

  • chemical cleaning may be required

After analyzing the benefits and limitations of water filtration system that apply membrane filter, it may be suitable to you depends on your lifestyle and budget i.e. initial budget and long term budget.