The UPC builds a plant to produce bio-products and bioenergy from wastewater using microalgae

+
Download

Pilot plant for the production of bio-products and bioenergy installed in the Agròpolis.

+
Download

The horizontal tubes of the photobioreactors, manufactured with polyethylene with an anti-UV treatment and forming a two-way circuit.

+
Download

Left to right: Joan Garcia, director of the UPC’s GEMMA research group; María Jesús García, a researcher of the same group; and Dulce Arias, a predoctoral student.

+
Download

Petri dish with algae isolated from photobioreactors.

+
Download

Cyanobacteria under the fluorescence microscope.

The Environmental Engineering and Microbiology Group (GEMMA) of the Universitat Politècnica de Catalunya (UPC) has built a 30-m3 pilot plant for the production of bioproducts and bioenergy from microalgae grown in wastewater. The plant has been installed in the Agròpolis, an experimental site located in Viladecans and forming part of the UPC’s Baix Llobregat Campus.

Jun 26, 2018

At the bioproduct production plant that was built in the Agròpolis, in Viladecans, researchers are studying how to produce new energy resources and valuable products from agricultural and domestic wastewater within the framework of the European project INCOVER . This project includes the recovery of energy in the form of biomethane and the obtaining of other products such as bioplastics, biological fertilizer and water for irrigation.

With the capacity to treat a volume of 2,000 to 8,000 litres of contaminated wastewater, the equivalent of that produced by a small housing block, the pilot plant consists of three tubular photobioreactors (transparent, closed production systems) of 10 m3 each that are used to grow microalgae from agricultural and domestic wastewater. It also includes a lamellar decanter for separating the biomass from the treated water. One part of the biomass is digested by a 1-m3 anaerobic digester from which biomethane is obtained and another part is used for accumulation of bioplastics (polyhydroxyalkanoates, PHA). The solid residue from this digestion is stabilized in a 6-m2 artificial wetland, also built in the Agròpolis, where biofertilizers are produced. Finally, the water treated in these photobioreactors is subjected to ultrafiltration and solar disinfection, followed by phosphorus adsorption and, thanks to an intelligent irrigation system, it can be reused to irrigate a field of up to 250 m2.
 
The biomethane obtained is much richer than that obtained in conventional digestion processes, where it passes through an absorption column that retains volatile gases and other pollutants that diminish the product's richness.

Algae to generate bioplastics
Researchers at the UPC’s Environmental Engineering and Microbiology Group (GEMMA), led by Professor Joan García, of the Department of Civil and Environmental Engineering, have demonstrated the ability of certain types of microalgae (cyanobacteria) to produce and accumulate bioplastics. The photobioreactor conditions can be adapted to increase the population of these organisms, which can synthesize and accumulate bioplastics in the form of granules in the cytoplasm of the cell as a reserve of nutrients. The properties of these bioplastics are very similar to those of traditional plastics from the petrochemical industry, with the advantage that they are totally biodegradable. Now the researchers are also investigating how to use them in the packaging market. Production is expected to achieve 1.5 kg of bioplastics per day.

From waste treatment to resource production
Urbanization, climate change, intensive agriculture and pollution, among other factors arising from human activity, pose a threat to water resources. Up to now the large volume of urban wastewater has been at best treated and then returned to the environment. A small amount of it is also used for irrigation. Catalonia is one of the autonomous communities in which it is most reused, but only 10% is used for irrigating gardens or farms. Agricultural drainage water is also a serious problem because it is loaded with nutrients, pesticides and herbicides.

Currently, water shortage and water pollution are one of the main environmental issues to be dealt with, and the management of this resource is particularly important in the countries of the Mediterranean basin. In order to deal with this problem, water treatment and reuse strategies should be implemented, and water should be used responsibly.

The European Union has launched initiatives to fund innovative ideas. The INCOVER project began in June 2016 under the Horizon 2020 programme, in response to the need for new solutions in water treatment and reuse. The main objective is to develop innovative and sustainable technologies for the treatment of waste water that also generate value-added products and zero waste.

This marks a change in the concept of the technology from waste treatment to resource production, thereby contributing to the generation of a circular economy.

The INCOVER project coordinated by the Aimen Technology Centre recently received the United Kingdom's Water Industry Award 2018 in the category Sludge & Resource Recovery.


Two more pilots, in Almeria and Germany
Two other pilot research plants are included in the INCOVER project: one at the Aqualia facilities in Chiclana de la Frontera, Cadiz, with a demo installed in a plant in Almería, and the other in Germany. The objectives of the research team in Almeria are similar to those of the UPC line: to use solar systems to obtain bioplastics, methane, biological fertilizers and disinfected water, and to reuse the water for irrigation. The main difference is that high-rate ponds (open systems) rather than photobioreactors (closed systems) are used to grow the microalgae. The solar disinfection system is also different and the treatment to obtain fertilizers is not performed in wetlands, but in tree plantations.

The third line of research, which is being carried out in Leipzig, Germany, is different because the aim is to create yeast rather than microalgae. In this case, bioreactors are fed with wastewater from the kitchens of the research institute and will generate organic acids rather than bioplastics. The yeast residue is processed to obtain biological charcoal instead of methane and active carbon instead of biological fertilizer.