Current and potential uses of composted olive oil waste

Food industry will have to focus on waste avoidance as well as utilisation of process waste. Application of clean technologies greatly enhances the safety and quality of the product as well as reducing the energy requirements and environmental impact of the food industry. The main environmental impacts of the food sector are aquatic, atmospheric and solid waste emissions. Nowadays, the main treatment method of solid wastes is composting, while recovery and reuse of by-products and wastes as raw materials stand for another effective option (http:// www.oulu.fi/resopt/wasmin/pap.pdf). Composted olive oil waste can find applications (1) as amendment in agriculture because of its high nitrogen and phosphorus content, (2) as a biofertiliser, with a mixture of compost with Sphagnum peat or commercial substrate finding use for ornamental plants growth and (3) as a biofilter for toxic metal removal. However, there are a number of disadvantages as well, such as large decline of soil germination capability, necrosis of the leaves and slow emission of secondary stems, and enhanced phytotoxicity, because of pH neutralisation technique, which should be seriously taken into account prior to opting for composting as a promising waste treatment alternative