Peels and pulp

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Description

In case of extraction of vegetable or fruit juice, high amount of peels and pulp are produced. For example, the orange peels waste coming from the orange juice industry represents approximately 50-60% of the orange fruit transformed. The orange peel waste is composed by: whole peel or rind (pericarp), pulp (called rag in the industry), seeds and aqueous emulsions from citrus processing plant.

Valorisation techniques

Anaerobic digestion in agro-industrial biogas plants or in anaerobic digesters dedicated to treat sludge from wastewater treatment plants (normally urban WWTP) . Anaerobic co-digestion is a technically feasible alternative for valorise orange waste, producing renewable energy while preventing their disposal to landfill. Orange peel shows high methane potential, high anaerobic biodegradability and kinetics degradation. Ruiz et al. 2011 showed a maximum orange peels specific biogas production of 1,100 L/KgTS. The complete orange degradation is achieved after 11 days. The co-digestion with other organic wastes avoids inhibition caused by limonene. The maximum percentage of citrus waste to keep a high and stable methane production is a topic that shall be defined in each blending of co-substrates.

Flow diagram of the demonstration biogas plant including co-digestion of orange wastes with cattle manure

Source: AINIA

• Composting
• Essential oils, pectin or proteins extraction
• Ethanol production
• Pollutant absorption
• Production of bents and paper pulp supplements

References

• Ruiz-Fuertes M.B., Kaiser F., Andrade-Montealegre D.P., Póvez A., Gronauer A. 2011. Methane Yield Improvement in Anaerobic Co-Digestion of Valencia Late Oranges and Cattle Manure. [poster] 11th World Congress on Anaerobic Digestion (AD11). International Water Association (IWA).
• Ruiz-Fuertes M.B., Kaiser F.L., 2007 Andrade-Montealegre D.P., Póvez-Loyola A.C., Gronauer A. (2007). Methane yield improvement in anaerobic co-digestion of Valencia Late oranges and cattle manure. Proceedings of 11th IWA World Conference on Anaerobic Digestion, Brisbane, Australia.

Back to Biobased products in wine/beverage
Back to EFFICENCY FINDER OF FOOD INDUSTRY