PROJECT DESCRIPTION
BACKGROUND
Europe is the world’s second biggest producer of fruit and vegetables. The sector accounts for 17% of total EU agricultural output value and involves approximately one million farms specialised in cultivation of fruit and vegetables. Fruit and vegetable processing is also a major industry. In 2013, an estimated 10 000 EU companies processed fruit and vegetables as their main activity, employing more than 280 000 people. Processing includes the preparation, preservation, canning, freezing and drying of fresh produce and the manufacture of fruit and vegetable juices.
Fruit and vegetable processing uses large quantities of water, as an ingredient, for cleaning produce, as an efficient transportation conveyor of raw materials and as the principal agent in sanitising plant machinery and areas. Processing activities generated an estimated 200 million m3 of wastewater in 2014.
The technical working group for the review of the reference document on Best Available Techniques for the Food, Drink and Milk Industries agreed in 2014 that emissions to water were the most pressing environmental issue in the fruit and vegetable processing sector. The working group agreed to collect data on wastewater emissions and on specific loads to better understand the environmental impact of the sector. Though water use will always be a part of fruit and vegetables processing, it has become the principal target for pollution prevention.
OBJECTIVES
The LIFE ALGAECAN project aimed to demonstrate the feasibility of applying solar-powered algal treatment to the effluents generated by fruit and vegetable processing.
The proposed treatment system involves three main steps:
- A two-phase microalgae growing system, which consumes the organic matter and nutrients contained in the effluent;
- A separation step to recover the clean water (that will comply with reuse standards); and
- A drying step to recover the dry microalgae as a valuable product that can used as a raw material to produce bio-fertilisers, animal feed and bioplastic.
Part of the purified water would be used to dilute the input effluent and the rest would be used to water green areas around the demonstration facility, or for the cleaning of trucks and equipment. The system was demonstrated at two facilities in Spain and Slovenia and the findings transferred to two additional facilities in Greece and Germany.
The project results support the implementation of the EU Water Framework Directive, the Roadmap to a Resource Efficient Europe and the Circular Economy Action Plan. In line with the 2009 Renewable Energy Directive, this LIFE project’s concept for wastewater treatment envisaged the use of renewable energy (solar and biomass) in order to minimise greenhouse emissions compared to standard treatment models.
RESULTS
The LIFE ALGAECAN project created a pilot plant to demonstrate the feasibility of applying solar-powered algal treatment to the effluents generated by fruit and vegetable processing. The plant was able to treat around 1 m3 of wastewater per day at two demonstration sites – for six months at the HUERCASA facilities in Sanchonuño (Segovia) and for another six months at the VIPI facilities in Brezje (Ljubljana). The treated water was shown to be suitable for re-use in cleaning or irrigation, according to the residence time of the centrifugation or the addition of a filtration stage.
The main outcome was the overall demonstration that the cost of wastewater treatment for the fruit and vegetable processing industry could be reduced by more than 80% compared to a traditional aerobic treatment plant, using solar radiation and biomass as energy sources and avoiding traditional costs associated with aerobic sludge management.
Furthermore, the project process also produces 1.5 kg of microalgae by-product powder per m3 of treated wastewater. The project team carried out an assessment of the valorisation of this by-product, which can be used as an organic fertiliser comprising 6% nitrogen, 2.5% P2O5 and 1.5% K2O, and as a raw material in the manufacture of animal feed with a lipid, protein and carbohydrate content of 15%, 40% and 20% respectively. The team affirms that algae could viably be marketed as a solid NPK biofertiliser in line with EU legislation. Additionally, it could be effectively incorporated into feed of a range of animals, replacing a significant part of animal feed.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).
