There is currently no proper management strategy for the waste that comes from pruning citrus trees. The most prevalent method is burning pruned material directly on site. This, however, causes environment issues concerning the emission of greenhouse gases, soil fertility, desertification, the pollution of surface waters and an increase in wildfires.
Over 310 000 hectares of citrus crops are currently cultivated in Spain. The main areas of production are the regions of Valencia and Murcia. Almost 200 000 ha are grown in Valencia. In around 30% of this area burning is the management technique used to get rid of pruning waste.
The project area lies in the municipality of La Vall d'Uixo where around 1 250 ha of citrus trees are cultivated. It is a traditional citrus growing region with characteristics that are common in many other citrus growing areas in Europe and around the world.
LIFE ECOCITRIC aimed to demonstrate the technical, economic and environmental viability of a new system for the utilization of agricultural waste produced by pruning citrus trees. The project advocated the sustainable management of this waste and demonstrated the environmental and economic benefits of this new system to the citrus fruit industry.
The process proposed by the project aimed to divide the treatment of pruning waste into two distinct stages: one for treating leaves and one for wood. The process was demonstrated in a newly installed pilot treatment plant in La Vall d'Uixó. The citrus-tree leaves were treated by a series of chemical and physical processes - including distillation and hydrolysis – in order to obtain essential oils, fertiliser and animal feed. The wood was transformed into pellets for fuel and animal bedding. All of these products were then commercialised.
The project also carried out an assessment of agricultural practices on local citrus fruit farms. This information was be entered into an online database and used to facilitate the implementation of the project and to help improve the management of agricultural land in the municipality.
The two main outcomes of LIFE ECOCITRIC are: an online tool that systematises citric cultivation in the region and the demonstration of the technical, economic and environmental viability of a new system for utilizing the agricultural waste from pruning citrus trees in La Vall d´Uixó.
During the preparatory phase, a SIG web-based tool was used to collect and identify data from the municipality’s five citrus cooperatives. The data parameters include: localisation, cultivated area, cultivated varieties, area per variety, annual production, destination, type of irrigation, type of pruning, month of pruning, type of pruning waste management, annual cost for elimination of the pruning waste. An online database based on Google Maps was created from the information and using cadaster information. It allows users to access data about all of the cultivated plots in the area. It will be managed by the local council once the project is finished. In addition, an online agricultural map was produced of the area and the most significant plots have been given QR codes for monitoring purposes.
LIFE ECOCITRIC also designed, constructed and tested a new pilot treatment plant which contained a new, innovative treatment system called ECOCITRIC. This system enables the production of products with high added value from the waste material. The innovation of this system is not so much in the technology used but in its high functionality. It joins together different technologies into a single process, enabling up to four products to be obtained.
The pilot plant constructed is able to treat 100 tonnes a year of citric pruning. It is made up of a separator, distillation system, drying system, management system and palletizing system. An innovative system (Lifth) was designed by Heliotec to improve the process of separation of the leaves and wood. It is a cutting-edge design that enables two materials that are very similar and of low density to be separated. A new bio-drying system was also developed and used during the project to reduce the moisture in the waste heat.
The tests on the pilot plant provided valuable data on how it might work before it is scaled-up to treat 100 000 tonnes of waste a year. The results showed that the plant is technically feasible, environmentally beneficial and economically viable. The products obtained from leaves and wood of citrus trees were: essential oils, animal feed, bedding straw and biofuel.
The two main outputs of the tests were the essential oils and the animal feed – these were the products that found the best market. The animal feed showed the best results. It can be mixed with other food (up to 80%) and produce a Low Carbon Feed suitable for goats. The essential oils also found a market particularly with regards to lemon essence. In addition, the pellets produced are being marketed for use in horse beds and as biofuel. Policy-wise, this project is totally in line with the EU Waste Framework Directive (2008/98/EC) and the Circular Economy package.
The following main lessons were learnt during the project: - The small plots of traditional citrus agriculture in Spain make the collection of waste difficult; - The waste should be crushed at the treatment plant, not in the field because the crushing starts leaf fermentation and important proteins and essences are reduced; - Lemon essence has more market demand than orange and mandarin essence; - The use of pesticides on the fields may contaminate the animal feed.
Heliotec is now installing an industrial scale production plant in Fuente Álamo (Murcia), which is backed by private investors. The plant will produce biomass, forage for ruminants (goats in particular) and limonene and lemon petit grain essential oils for distribution in cosmetics and perfumes initially from 10 000 tons of lemon pruning. There are a number of farmers interested in using the new ECOCITRIC system for their waste. In some areas they will work together to collect the waste more efficiently. In addition, several national and international investors are interested in replicating the industrial facility in their citrus zones. Project partners have also applied for LIFE funding for a project that will look at the formulation of a compound feed made with different types of agricultural waste.
Implementation of the ECOCITRIC system on a large scale will decrease the risk of wild fire, reduce the carbon footprint by 90% and help reduce the Greenhouse effect, save costs for agriculture producers, improve the quality of life for farmers and reduce particles in the air.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).