In vegetable oil refining process (olive or seed oil) the oil acidity must be corrected by sodium hydroxide. Such operation produces soaps that are usually removed by centrifugation generating an effluent called “saponified waters” (SW), containing organic and inorganic compounds.
SW are treated by acid (sulfuric or phosphoric) to convert soaps into oleins, which are recovered as valuable byproduct.
In conventional treatment systems the oleins are recovered by natural gravity separation; such a technique has a number of disadvantages:
- oleins separation requires long residence time and consequently this operation needs large tanks and huge space.
- only a part of the oleins can be separated by gravity, the balance part remaining in the water as emulsion.

Thus the effluent from the refining process is heavily polluted for the presence of oleins, fatty acids and high content of salts such as sulfates and phosphates that can not be discharged without a suitable treatment.
HYDRO AIR RESEARCH has developed an advanced effluent treatment process (ETP) based on membrane technology that allows the complete oleins recovery and water reuse.

The first step of HAR removes the oleins from the water recovering 100% of the product at high rate giving an effluent completely oil free.
This stage removes more than 90% COD and 100% oleins.
As the effluent after 1° step still contains same organics and all salts, according to HAR process the effluent is then treated by NARO system, a very efficient HAR patented Reverse Osmosis system able to remove the salts and the balance COD fraction, delivering a low conductivity water that can be reused for the factory services.