Urban Biorefineries in the EU: From Blueprint to Implementation

(World Bio Market Insights) Cities are overflowing with valuable biomass if you look in the right places: namely, in their sewage systems. The organic materials in urban wastewater can provide cheap, local, and abundant raw materials for biobased and circular fuels, fertiliser, and materials.

Valorising this waste means setting up urban biorefineries that can extract plant and animal materials from sewage streams and process them into safe products.

But are urban biorefineries economically feasible? Or are they an ideal dreamt up by urban planning researchers?

Two European projects are proving the concept is a viable sustainable policy tool for municipal authorities and a profitable activity for waste management companies.

The most obvious function is that they would help purify sewage streams and help city water use efficiency.

Yet existing wastewater plants also do this. What sets the urban biorefinery apart is that at the same time as it purifies wastewater, it churns out high value raw materials from the waste it extracts.

This supports the third purpose of the urban biorefinery. The fact it squeezes high value goods out of waste means it can, in theory, lower the cost of municipal wastewater management.

Selling goods made from wastewater recoups some costs of its purification, the argument goes, meaning public and private entities are incentivised to prevent untreated sewage entering the environment.

The urban biorefinery is far from being an everyday piece of urban infrastructure. However, EU organisations are trying to tackle the technical, cultural, and economic challenges of realising this.

Between 2017 and 2022, the Bio Based Industries Joint Undertaking (BBI JU) funded the EU URBIOFIN project. URBIOFIN aimed at showing the technoeconomic feasibility of turning urban waste into fuel and materials, making municipal waste management more circular as a result.

To achieve this aim, URBIOFIN established lab, pilot, and semi-industrial demos of an urban biorefinery design in three spots across Spain. The first module that made up the URBIOFIN three-part biorefinery was located in PERSEO Biotechnology’s plant (L’Alcudia, Valencia). Modules two and three were sited in the Innovation Centre of Urbaser (Zaragoza) and the CLAMBER biorefinery (Puertollano, Ciudad Real) respectively.

This three-part system was designed to be modular, meaning anyone who is actually implementing it can pick and choose which segments they want to set up, depending on factors such as budget or which biobased products there are markets for.

Each segment of the URBIOFIN biorefinery took in different inputs and yielded different biobased products. Some of the outputs created in the first or second modules can become feedstock for later stages in the production line.

In the first site, organic matter from urban waste is turned into bioethanol and bioethylene.The bioethanol byproducts from the first module are sent onto the second module, which makes natural polyesters from volatile fatty acids. These natural polyesters can be further processed into biopolymer-based consumer goods. The second module also produces biogas.

The third module features microalgae, which are used both as a biomanufacturing tool and as an ingredient for organic fertiliser outputs.

In module three, biogas from module two can be delivered to the microalgae, which convert the gas into either biomethane – a higher value product useful as vehicle fuel or for the power grid – or PHA biomass, feedstock for PHA plastic particularly suited to agricultural and horticultural applications.

The same algae can then be hydrolysed and concentrated, producing either dry granular fertiliser or liquid biobased stimulants for the agricultural market.

The biobased fertiliser industry is another sector that would benefit directly from the biorefinery tested in the programme. The EU’s Products Regulation of 2019 is set to grow the European market for organic fertilisers. Demand is set to expand further thanks to the EU target of putting more land under organic farming.

URBIOFIN ended in 2022 but the HOOP project, backed by the EU’s CORDIA, has taken up its mission to mainstream the urban biorefinery.

While UROBIOFIN aimed to demonstrate technoeconomic feasibility, HOOP is focused on pathways to implementing bioeconomies in concrete contexts.

Rather than focusing narrowly on biorefinery design, HOOP is interested in how to adapt biorefinery and waste collection systems to specific urban ecosystems where they operate, local contexts marked by unique infrastructures, populations, and waste content.

HOOP envisages more varied and emerging industries based on wastewater feedstock, including rearing economically useful bacteria or insects on feed using waste.

This interest in novel products has an economic purpose: some niche compounds can fetch higher market prices than biofuels or compost, pushing up the economic viability of the plant. READ MORE