An eco-compatible process for the depuration of wastewater from olive mill industry

Innovative method for recovery and valorization of hydroxytyrosol from olive mill wastewaters

The nutritional properties of olive oil can be attributed to its oleic acid and phenolic compounds content, acting as natural oxidants to prevent human diseases. In particular, hydroxytyrosol has an anti-inflammatory action similar to omega 3 fatty acids from fish oil. The olive oil production was conducted by two extraction procedures: first, a two-phase extraction giving extra-virgin olive oil and humid pomace, second, a three-phase working process of humid pomace, obtaining another minimum quantity of extra-virgin olive oil, 'dry' pomace devoid of polyphenols, and mill wastewaters rich in anti-oxidant compounds. The aim of this processing was to employ water to extract the highest concentration of polyphenols from humid pomace and convey them in oil mill wastewaters for extraction. Processed olives were 37,200 kg, pomace deprived of polyphenols was equal to 20,400 kg and processing was performed with 500 kg of olives per hour. This method offers advantages of using cheap equipment and technical simplicity.

A physicochemical-biotechnological approach for an integrated valorization of olive mill wastewater

An integrated physicochemical-biotechnological approach for a multipurpose valorization of olive mill wastewaters was studied. More than 60% of the wastewater natural polyphenols were recovered through a solid phase extraction procedure, by employing Amberlite XAD16 resin as the adsorbent and ethanol as the biocompatible desorbing phase. Thereafter, the dephenolized effluent was fed to a mesophilic anaerobic acidogenic packed-bed biofilm reactor for the bioconversion of the organic leftover into volatile fatty acids (VFAs). A VFAs concentration of 19 gCODL(-1) was obtained, representing more than 70% of the COD occurring in the anaerobic effluent. The biotechnological process was assessed by means of bio-molecular analyses, which showed that the reactor packed bed was mostly colonized by bacteria of the Firmicutes phylogenetic group. The biorefinery scheme developed in this study allowed the obtainment of 1.59 g of polyphenols per liter of wastewater treated and 2.72 gCODL(-1) day(-1) of VFAs.

Resorcinol degradation by a Penicillium chrysogenum strain under osmotic stress: mono and binary substrate matrices with phenol

A phenol-degrading Penicillium chrysogenum strain previously isolated from a salt mine was able to grow at 1,000 mg l(-1) of resorcinol on solid medium. The aerobic degradation of resorcinol by P. chrysogenum CLONA2 was studied in batch cultures in minimal mineral medium with 58.5 g l(-1) of sodium chloride using resorcinol as the sole carbon source. The fungal strain showed the ability to degrade up to 250 mg l(-1) of resorcinol. Resorcinol and phenol efficiency degradation by P. chrysogenum CLONA2 was compared. This strain removes phenol faster than resorcinol. When phenol and resorcinol were in binary substrate matrices, phenol enhanced resorcinol degradation, and organic load decreased with respect to the mono substrate matrices. The acute toxicity of phenol and resorcinol, individually and in combination, to Artemia franciscana larvae has been verified before and after the bioremediation process with P. chrysogenum CLONA2. The remediation process was effective in mono and binary substrate systems.