CORDIS

Considering the strong EU commitment towards full implementation of a European circular economy, RES URBIS aims at converting several types of urban organic waste into valuable bio-based products, in an integrated biorefinery and by using one main technology chain.
Urban organic waste include the organic fraction of municipal solid waste, excess sludge from urban wastewater treatment, garden and park waste, and selected waste from food-processing. Bio-based products include polyhydroxyalkanoate (PHA) and related PHA-based bioplastics as well as biosolvents (to be used in PHA extraction) and fibers (to be used for PHA biocomposites).
The technical goal of converting organic waste into the above mentioned bioproducts will be combined to territorial and economic analyses, made with reference to different territorial clusters and either considering the ex-novo implementation of the waste-based biorefinery or its integration into existing anaerobic digestion plants. The market analysis will be based on a portfolio of PHA-based bioplastics, to be tested for use as:
- Biodegradable commodity film
- Packaging interlayer film
- Speciality durables (such as electronics)
- Slow C-release material for groundwater remediation

A graphical sketch of the RES URBIS concept is shown in Fig. 1 and the RES URBIS geographical map is shown in Fig. 2. Fig. 3 shows a picture of the Res URBIS people in its IV meeting in Barcelona.

RES URBIS work is organized in 8 Work Packages which are divided into Tasks (Fig. 4). In the 1st half of the project, all WPs and most Tasks started and the following main results were achieved:

- Long-term PHA production is feasible at pilot scale, starting from true organic waste (WP2): Two pilot plants were continuously operated to produce PHA. One plant (Fig. 5) was fed with liquid waste from fruit processing and the other one (Fig. 6) with a mixture of liquid slurry after squeezing of the organic fraction of municipal solid waste and excess sludge from urban wastewater treatment. In both plants the PHBV copolymer (3-hydroxybutyric and 3-hydroxyvaleric monomers) was produced, with average HV content ranging between 10% and 20% w/w, depending on feedstock composition and operating conditions. In parallel, three more plants are in operation to further develop the acidogenic fermentation step.
- A 1° generation of PHA batches was prepared (> 12 kg) and delivered for PHA extraction and downstream processing (WP2, WP3). A set of different extraction methods is under investigation using either inorganic reagents or organic solvents, in both cases chlorine-free. Preliminary results validated the extraction of PHA from the biomass with more than 90% purity and using reduced reagent quantities when compared to the initial protocols. It is also relevant that the polymer remains white after melting test (Fig. 7). Also, PHBV-biomass samples were succesfully extracted, electrospun, and characterised (mechanical and barrier properties) in comparison to commercial PHBV.
- Possible presence of microcontaminants (WP3): Representative contaminants, such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals, were analysed in raw materials (i.e. dried PHA-rich biomass) and on extracted PHA samples (by using conventional extraction methods). First data on selected PAHs and Cd show that their concentration meets present regulatory standards.
- The regulatory framework has been analysed and barriers/gaps individuated (WP4). The EU regulation on waste sector has very recently been updated to conform to new challenges of the circular economy package. Whereas this opens good perspective for RES URBIS value chain, a regulatory gap could rise because of the need of defining appropriate “end of waste” criteria (in particular for new technologies and new products). Also, it was found that being polymers, PHA are exempted from REACH and ECHA registration, unless PHA has a level of impurities which is more than 2% and whose composition is not known.
- The waste/sludge management systems of 5 territorial clusters have been described and analysed (WP1, see an example in Fig. 8); and data supplied for technical economic analysis of new scenarios according to the RES URBIS value chain.
- A preliminary business model has been defined (WP5); technical economic analysis is in progress, with reference to best territorial scenarios, by including all relevant data blocks (Fig. 9). On this basis, the road map to bring RES URBIS to the demo scale is being defined (Fig. 10)
- A screening LCA has been performed (WP1) Preliminary results suggest that the RES URBIS concept is performing similar or slightly better than traditional anaerobic digestion, similarly to incineration, and better than landfilling. However, significant differences are seen in function of the local conditions (e.g. for incineration) and across impact categories, meaning that further and more precise interpretation is needed. For this purpose, a global sensitivity analysis was performed on >900 parameters (Fig. 11).
- Social perception has been investigated; a first questionnaire on has been launched (WP4): This has been realized by exploring the consumers’ acceptance of urban bio-waste products. Our findings respect an UK sample show a general consumer acceptance, focusing in our study on designer vs convenience chairs, derived from municipal organic waste. Older consumers displ

At the end of the project, we aim to demonstrate (at TRL 5-6) the whole RES URBIS technology chain to convert organic waste of urban origin into PHA-based bioplastics, by taking care of all technical and non technical aspects (economical, regulatory, social and environmental). The value chain is expected to be flexible enough to cope with different waste management systems, to be easily integrated with existing plants, and to offer economic gain with respect to benchmark treatments while maintaining PHA at an affordable price for the tested product portfolio. If all these aspects are solved, the RES URBIS value chain could affect waste management systems for territorial clusters of more than 500.000 inhabitants (i.e. where more than 340 million European live) or even more generally linked to existing AD supply chain, with relatively large capacity for treating biowaste.