DEEP PURPLE: Conversion of mixed urban bio-waste into high value-added products in a flexible biorefinery

Planta de tratamiento de aguas residuales

The DEEP PURPLE project (2019-2023) aims to develop and validate a versatile, integrated and flexible biorefinery capable of taking advantage of the organic urban waste streams to extract and recover high added value compounds (ectoine, PHA or cellulose), used for fertilizer, cosmetics and bioplastics sectors.


Up to 138 million tons of bio-waste, coming from wastewater treatment and urban waste management are annually generated in the European Union. It is estimated that almost 75% of this waste is sent to incineration or landfilling, which represents a huge environmental and economic cost. These valuable resources are lost every day by not utilizing the nutrients and compounds in sewage and organic waste to its full potential.

The heterogeneity of waste streams and their high level of dilution make the process of separation at source difficult and reduce the effectiveness of both conventional and emerging methods of treating urban organic waste. This heterogeneity, together with the high pollution of these streams, hampers an efficient recovery of resources.

Summary and objectives

The aim of the DEEP PURPLE project, funded by the Bio-based Industries Joint Undertaking under the European Union’s Horizon 2020 programme, is to extract and recover high added-value compounds from urban waste streams (mixed waste streams, separately collected organic waste, wastewater and the organic fraction of sewage sludge) for bio-based products of several industrial sectors.

DEEP PURPLE presents a radically new vision for waste valorisation that will combine a number of state-of-the-art waste treatments (preconditioning, separation and purification processes), with a breakthrough treatment technology based on Purple Phototropic Bacteria (PPB).

To this end, a versatile, integrated and flexible multiplatform biorefinery will be developed in this project, creating five new value chains to obtain three raw materials for the bioindustry. On the one hand, within the concept of biorefinery proposed in DEEP PURPLE, cellulose will be recovered from urban wastewater for its subsequent validation in bioplastics that will be validated to obtain cellulose containers and nanofibers which can be used as reinforcements of other bioplastics. On the other hand, the organic fraction of urban solid waste will be used to produce ectoine – a substance with hydrating, regulating and soothing properties for the skin – to be used in cosmetics. Furthemore, Purple Phototrophic Bacteria (PPB) will be used, as they are capable of metabolising compounds of difficult degradation under different conditions thanks to their versatile metabolism, obtaining a rich biomass that will be used for the extraction of biofertilizers and PHAs.

This innovative biorefinery concept proposed by DEEP PURPLE will allow the development of a new generation of integrated urban bio-waste recovery facilities where MSW and wastewater are treated in the same facility, thus creating multiple synergies that are not available within the conventional urban bio-waste scheme.

The concept of DEEP PURPLE biorefinery will be validated through the implementation of various sites, both in Spain (Madrid and Toledo) and in the Czech Republic (in the Moravia-Silesia Region).


14 partners from 6 European countries:

1. FCC AQUALIA (Spain) – Project coordinator

2. ACTIVATEC (United Kingdom)

3. RNB S.L (Spain)


5. FCC SA (Spain)

6. ITENE (Spain)

7. BRUNEL UNIVERSITY (United Kingdom)

8. NOVAMONT (Italy)



11. UNE (Spain)

12. GATE2GROWTH (Germany)



ITENE’s role

The DEEP PURPLE project is organized in 8 work packages (WP), and ITENE is involved in several WP and tasks. In WP1, ITENE will define the decontamination procedures for the cellulose recovered from wastewater and sewage sludge. The decontaminated cellulose will be then valorised by ITENE in WP2 with two different approaches:

(i) by means of their saccharification into fermentable sugars for its further use in the downstream processes to obtain polyesters (bioplastics) and

(ii) by the production and surface modification of Nanofibrillated Cellulose (CNFs), that will be used to produce nanocomposites of PHA reinforced with CNFs, which ITENE will validate for packaging applications in WP4 at lab scale.

Moreover, ITENE is the leader of WP5, which is related to the environmental, social and economic assessment of the DEEP PURPLE processes and their final products. ITENE will assess the environmental impacts thought a full life cycle assessment (LCA). ITENE will also contribute in terms of dissemination, exploitation knowledge transfer in WP7.


Decontamination procedures

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