The “nectar of the gods” is considered the healthiest vegetable oil of all and is correspondingly sought-after in kitchens throughout the world. Agricultural businesses in the key cultivating countries such as Spain, Italy, Greece or Turkey etc. are now subject to significant competition pressure. For these countries, it is important to achieve the maximum possible yield for the least possible energy expenditure and to ensure first-class product quality at the same time. In addition, however, environmental protection is becoming more and more important.
GEA Westfalia Separator Group supports companies with innovative processes such as obtaining oil in 2-or 3-phases or processing pomace with all capacities being manageable to the same high quality.
This 2-phase system, developed by GEA Westfalia Separator Group in the early Nineties, manages to perform dilution without the addition of water and produces correspondingly less waste water.
Complete process line from GEA Westfalia Separator Group with oil obtained in 2 phases and pomace processed in 3 phases
Once the leaves have been removed from the olives and they have been washed, they are finely milled in hammer mills with mesh widths of 5 to 7 mm and the mash stirred in a malaxer at max. 28 to 33 °C to release the oil from the fruit particles. For the subsequent 2-phase separation process, GEA Westfalia Separator Group developed a decanter with a special screw which separates the mash into oil and pomace.
In addition to reducing the quantity of waste water compared to former processes, the other benefits of this process are the increased yield and the first-class product quality. The decanters with Westfalia Separator® cetec technology launched in 2001 increased yield by another 1 to 2 percentage points.
A further benefit is the fact that valuable by-products can be obtained by treating the pomace. Some of the residual oil in the pomace is usually recovered by a second decanter stage with the pomace being separated into olive pits and pulp. Whilst the pits can be used as high-quality combustible material for the oil mills or for the ceramics industry, after drying, the pitless pulp can be sold as fertilizer or as a high-fiber feed additive.
Process water treatment by the Borras method
GEA Westfalia Separator Group also collaborated with a Spanish oil mill to develop a special decanter process which can be used to treat even the process water in a specific way. Although 2-phase technology does not require dilution water, water is used in other process stages, as with any process. Some 200 liters of water are required for every ton of olives processed. This process water can then become waste water, for example, still containing oil and extremely fine particles. When this is concentrated by sedimentation or flotation, we speak of residual sludge (Borras ≅ lees).
Whereas this mixed phase used to be more or less discarded, the Borras process opens up new possibilities. By treating the mixed phase with an additional 3-phase decanter in parallel with the obtaining of oil, the oil it contains can also be obtained in virtually similar quality. A 3-phase decanter with a high degree of separation precision separates both the residual oil and the extremely fine particles from the mixed phase.
Overall, the Borras method has three significant advantages: firstly, it reduces the waste water volume by 15 percent; secondly, all the parameters relevant for waste water assessment drop, meaning that waste water charges are also correspondingly lower; thirdly, the oil mill obtains up to another 0.5 percent of oil in relation to the quantity of olives processed.GEA Westfalia Separator Group supports companies with innovative processes,