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Reporting period: 2019-05-01 to 2020-10-31

Nowadays, up to 138 million tonnes of bio-waste are annually generated in the EU. It is estimated that almost 75% of this waste is either incinerated or landfilled, with a huge environmental and economic cost associated. On top of that, effective resource recovery is still hampered by heterogeneity of waste streams and ineffective separation at source. Biowaste and conventional wastewater keep relying on energy-intensive technologies while dissipating valuable components to be potentially recovered to produce bio-based products and materials. DEEP PURPLE project broke into this scenario by proposing an integrated treatment of urban bio waste in a novel Multi-Platform concept as a key option to implement a low-cost, disruptive urban bio-waste stream treatment based on the photo-biorefinery concept. This novel approach will be implemented by end-users from three municipalities, Madrid (ES), Toledo (ES), and the Moravia-Silesia Region (CZ) to enable the extraction and recovery of high added value compounds from urban waste streams through the production of bio-products such as slow-release fertilizers, fine chemicals, self-healing building materials and bioplastics for packaging.
DEEP PURPLE project aims to develop and demonstrate a photo-biorefinery concept as a key option to implement a synergistic treatment of urban bio-waste streams (wastewater, the organic fraction of urban solid waste (OFMSW) and sewage sludge). The rationale of the DEEP PURPLE project is based on the combination of optimized upstream and downstream technologies as core technology and an innovative wastewater treatment based on the use of purple phototrophic bacteria (PPB) in open pond anaerobic photobioreactors. These processes will be used for resources recovery from urban bio-waste to provide a secure and sustainable supply of biomass feedstock to be further transformed into high added-value products for different industrial sectors.

With these objectives, DEEP PURPLE is structured in three phases. The first phase deals with the optimization and upscaling of pre-treatment, conversion, and downstream processes from TRL 5 to 6. The second phase deals with the upscaling and demonstration of the photo-biorefinery concept at TRL 7 by integrating the processes at two demo sites (Spain and Czech Republic), and the third phase which focuses on the validation of the bio-based products, namely cosmetics, fertilizers, biopolymers for packaging applications and self-repairing construction material.
Optimization of pre-treatment, conversion and downstream processes at TRL 4- 5:
• Pretreatment: (i) efficiency of thermal hydrolysis for OFMWS 60%, (ii) successful decontamination of cellulose recovered from wastewater > 80% removal of volatile compounds.
• Conversion: i) anaerobic PPB photobioreactors at URJC (TRL 4): up to 20% conversion of C into PHA; anaerobic photobioreactors at WWTP Estiviel (TRL 5) producing effluent compliant with discharge limits and PPB-enriched biomass as organo-fertilizers; (ii) 95% biogas conversion into ectoine with 95% extraction efficiency upscaled to a 2-m3 demo reactor.
• Downstream: (i) 98% pure PHA obtained from biomass, 75% extraction efficiency; (ii) 90% yield of fermentable sugars from cellulose recovered from wastewater; (iii) 20% faster biodegradability of coextrauded films containing PPB- biomass PHA; (iv) PPB biomass supports up to 35% improvement of maize and soybean plant growth.

Upscaling from TRL 4-5 to TRL 7 of the above mentioned process ongoing.

Up to 15 key exploitable results have been identified within the project. Two of those where selected to be disseminated among international technical committees: low-cost wastewater treatment based on Purple Phototrophic Bacteria photobioreactors and biodegradable and compostable bioplastics. Both AQUA and NVMT have taken part in several meetings with national and international (ISO) technical committees.
DEEP PURPLE is promoting up to 4 new cooperation among bio-waste management companies and companies in the field of bioplastics, construction and build environment, fertilizers, and personal care & cosmetics sectors within the consortium according to the project exploitation strategy.
DEEP PURPLE is developing up to 4 new bio-based value chains that involve the development of industrial symbiosis models among municipal waste managers and end users from three different sectors.
It has been proved that the PPB biomass causes and improvement by 35% of plant growth (soybean and maize crops).
Ectoine from biogas has been extracted with 95% efficiency while decreasing production costs by 40% due to substitution of industrial substrate.
Upscaling of ectoine production and extraction process from TRL 4 (20 L) to TRL 7 (2 m3)
Co-extruded films with PHA have demonstrated to have a 20% faster biodegradability compared to other biobased and biodegradable counterparts.
95% pure PHA has been extracted from biomass with 75% efficiency.
DEEP PURPLE is transforming the OFMSW in a cascade-approach. In a first stage, hydrolysis of the waste is being transformed into a liquid hydrolysate hydrolysate with a hydrolysis efficiency of 60%, which is much higher than the predicted 35%.
Anaerobic co-digestion of this sludge with the solid fraction of the OFMSW after thermal hydrolysis increases the anaerobic digestion efficiency up to 70% of solids destruction (higher than 50-60% of anaerobic digestion with sludge)
On the other hand, regarding the environmental impact, with the DEEP PURPLE technologies, we have achieved, up to now, a recycle and reuse efficiency of 61.5% of the primary sludge and 78.5% of the secondary sludge, which is higher than the expected value of 58.2%. We also have demonstrated a reduction of the amount of landfilled organic waste by 76% and 70% compared to the current state-of-the-art solutions, which is traduced into 14440 tons/y. The amount of wastewater treated in DEEP PURPLE is estimated in 2781300 m3/y.