Forward osmosis in wastewater treatment processes

In recent years, membrane technology has been widely used in wastewater treatment and water purification. Membrane technology is simple to operate and produces very high quality water for human consumption and industrial purposes. One of the promising technologies for water and wastewater treatment is the application of forward osmosis. Essentially, forward osmosis is a process in which water is driven through a semipermeable membrane from a feed solution to a draw solution due to the osmotic pressure gradient across the membrane. The immediate advantage over existing pressure driven membrane technologies is that the forward osmosis process per se eliminates the need for operation with high hydraulic pressure and forward osmosis has low fouling tendency. Hence, it provides an opportunity for saving energy and membrane replacement cost. However, there are many limitations that still need to be addressed. Here we briefly review some of the applications within water purification and new developments in forward osmosis membrane fabrication.V zadnjih letih se membranska tehnologija vse pogosteje uporablja v procesih čiščenja odpadne vode in vode za proizvodnjo. Procesi membranske filtracije so enostavni za izvajanje in dajejo kakovostni produkt/filtrat za nadaljnjo uporabo tako v industrijske namene kot tudi za proizvodnjo pitne vode. Ena od obetavnih tehnologij za proizvodnjo vode in obdelavo odpadnih voda je proces osmoze. Princip delovanja osmoze predstavlja metodo čiščenja vode, ki deluje brez hidravličnega tlaka, kar zagotavlja trajnostno (nizkoenergetsko) tehnologijo obdelave vode. Gonilna sila je razlika v kemijskem potencialu med vhodno in gonilno raztopino, ki sta ločeni z membrano, prepustno samo za vodo. Prednost osmoze pred obstoječimi visokotlačnimi membranskimi procesi je ravno delovanje brez dodatnega visokega tlaka, kar vodi tudi k manj pogostemu mašenju membran. Torej, omogoča delovanje z nižjo porabo energije ter podaljša življenjsko dobo membran. Vendar pa še vedno obstajajo nekatere pomembne tehnološke pomanjkljivosti procesa. V prispevku je predstavljena uporabnost tehnologije osmoze pri različnih sistemih čiščenja ter razvoj proizvodnje osmoznih membran