the World Health Organization are 10 ppb and
1 ppb, respectively.
The main limitations of existing treatment
technologies are secondary contamination
by microbial cells, nutrients, and metabolic
by-products in biological processes; difficulties
in disposing the brine solution from pressure
driven membrane processes; high energy
demands in distillation processes; competition
for adsorption sites in ion-exchange systems by
other ions that are usually present in much
higher concentrations; and the undesirable
addition of chemicals, as well as difficulties in