Within the European project INCOVER, an experimental plant uses low-energy photobioreactors to cultivate micro-algae and transform wastewater into bioproducts.

This article describes this new experimental plant and the start-up stage, starting from the new design of three semi-closed horizontal photobioreactors with low energy requirements, for microalgae cultivation (30 m³ total), using agricultural runoff and urban wastewater as feedstock.

The inflow nutrients concentration is adjusted to select cyanobacteria, microalgae able to accumulate polyhydroxybutyrates, which can be used for bioplastics production. Part of the harvested biomass is used as substrate for anaerobic co-digestion (AcoD) with secondary sludge to obtain biogas. This biogas is then cleaned in an absorption column to reach methane concentration up to 99%. The digestate from the AcoD is further processed in sludge wetlands for stabilization and biofertilizer production.

On the other hand, treated water undergoes ultrafiltration and disinfection through a solar-driven process, then it is pumped through absorption materials to recover nutrients, and eventually applied in an agricultural field to grow energy crops by means of a smart irrigation system. This plant presents a sustainable approach for wastewater management, which can be seen as a resource recovery process, more than a waste treatment.

'The circular economy and the bioeconomy — Partners in sustainability' is the third EEA report on the circular economy. It aims to support the framing, implementation and evaluation of European circular economy policy from an environmental perspective. It shows that the two policy agendas have similar objectives and areas of intervention, including food waste, biomass and bio-based products, and that they would benefit from stronger links, particularly in product and infrastructure design, and collaboration throughout the value chain.

The increasing demand for food, feed, biomaterials and bioenergy resources could worsen the over-exploitation of natural resources. By extending the lifetime of products and recycling materials, a circular, bio-economy approach can help retain material value and functionality for longer time as well as avoid unrecycled biowaste.

Promising innovations and strategies for circular biomass use include biorefinery, 3D printing with bioplastics, multi-purpose crops, better use of residues and food waste, and biowaste treatment. Consumers can also contribute by eating less animal-based protein, preventing food waste and separating biowaste from other waste streams.

Implementing the circular and bio-economy in tandem, by applying specific design principles within a systemic approach, would improve resource efficiency and reduce environmental pressures.