Maintaining an effluent of constant quality as well as avoiding health
hazards are some of the main concerns in recycling water. A joint res
earch program funded by the Sydney Water Board and the research centre
of the French company Lyonnaise des Eaux shows that the ultrafiltrati
on process using polymeric membranes provides a permeate free of suspe
nded solids and BOD5. This process also provides good disinfection, wi
thout any byproducts or bacterial regrowth, by physically removing bac
teria and viruses.