What is Forward Osmosis?

In forward osmosis (FO), water molecules migrate by diffusion, without energy input, into a more concentrated “draw solution.” Energy for the process is supplied by osmotic pressure difference of the two solutions.

The dynamics of FO is opposite of Reverse Osmosis which requires energy to overcome the osmotic pressure difference.

Forward Osmosis mimics water transport by plants, when fresh water is drawn by osmotic pressure into the plant through its roots in the soil.

Forward Osmosis

 

In FO water molecules migrate by diffusion, without energy input, into a more concentrated “draw solution.” Energy for the process is supplied by osmotic pressure difference of the two solutions.

The dynamics of Forward Osmosis is opposite of Reverse Osmosis which requires energy to overcome the osmotic pressure difference. FO mimics water transport by plants.

  • FO membranes remove salts, xenobiotics, bacteria, small organics and other contaminants
  • FO membranes are low fouling: foulants do not compact on surface like UF & RO (no cake layer)
  • FO requires lower energy for certain processes.
  • FO can recover useful products from brine or waste streams while also purifying water for reuse

FO often requires separation of the purified water from the “draw solution.”

FO can operate in many system configurations:

FO Concentrator


FOconcentrator

FO/RO


FORO

FO/MD


FOMD

FO + specialized draw


FODraw

FO/MBR


FOMBR