Waste water from olive oil production, which is called "Alpechin" in
Spanish, is a waste water which contains large amounts of organic substances.
In most cases, it is collected in vaporization ponds or is directly conveyed
into the drainage ditch. This results in problems of smell and a dark, almost
black discoloration of lakes, rivers and canals.
Another problem might be the contamination of the ground water. The
treatment of the waste water in sewage plants and the irrigation of the waste
water onto fields is problematic due to the toxic effect of its polyphenol
content.
An environment-friendly solution is a plant in which the solid and the
liquid residues from olive oil production are treated. The high energy content
of the solid residues is used for the generation of electrical energy. They are
incinerated after dehydration and drying. The steam generated in the boiler is
used as motive steam for a turbine. The power generated by means of a generator
is supplied to the municipal power distribution network.
Part of the turbine exhaust steam of an approximate pressure of 0.16 bar is
used as heating medium for an evaporation plant. In the evaporation plant, the
waste water is concentrated from 5-50% TS. The concentrate can be used as
fertilizer or, after another increase of the dry substance content to approx.
65-70% TS, it can also be incinerated.
The evaporated water is condensed and can be used as process water. The
condensed turbine exhaust steam is transferred to the boiler.
The evaporation plant mainly consists of a falling film evaporator and a
forced circulation evaporator as high concentrator. The evaporator type is
selected in view of the specific product properties. The evaporator design is
based on evaporation tests which we carry out on the original waste water at
our R & D Center.