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Procedure for the solubilization of residues of citrus fruit squeezing

Biofuel - biogasCatalytic oxidizing treatmentCitrus pulpOrange peels solubilizationPollutant load reduction


The invention describes a process for the solubilization of residues of citrus fruit pressing. In particular, the present invention refers to a process for the transformation of the exhausted citrus peels, for example those of orange, into an aqueous liquid product with low content in organic polluting load, easily purified or, alternatively, in a stable product and storable.

Technical features

The invention consists in the realization of an integrated process which provides for a first solubilization step of the solid residue followed by a second catalytic oxidation step of the substances dissolved in said solution. The first phase consists in the solubilization of the orange peel by a basic treatment at a temperature between 30 ° C and 350 ° C and the second phase consists in reducing the polluting load of the previously solubilised peels, by an oxidizing treatment in the presence of oxygen and of heterogeneous catalysts at a temperature between 30 ° C and 350 ° C and an oxygen pressure ranging from 2-50 bar. The dual purpose of the process is to transform the orange peel into an aqueous liquid product and to reduce its organic load in order to make such wastewater more suitable for disposal in a purification plant. Alternatively, the process can be blocked at the end of the first phase.

Possible Applications

  • Citrus processing industries;
  • Purification plants.


  • Industrial Citrus waste disposal directly in the common biological purification plants;
  • Re-use or storage, after possible concentration, of the product obtained from the solubilization process;
  • Rapid reaction times.