Periodic Reporting for period 2 - DEEP PURPLE (CONVERSION OF DILUTED MIXED URBAN BIO-WASTES INTO SUSTAINABLE MATERIALS AND PRODUCTS IN FLEXIBLE PURPLE PHOTOBIOREFINERIES)
Periodo di rendicontazione: 2020-11-01 al 2022-04-30
Nowadays, up to 138 million tonnes of bio-waste are annually generated in the EU. 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 still relies on energy-intensive technologies while dissipating valuable components to be potentially recovered to produce bio-based products and materials.
DEEP PURPLE project proposes an integrated treatment of urban bio waste in a novel multi-platform concept 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 DEEP PURPLE project is based on the combination of optimized upstream and downstream technologies and an innovative wastewater treatment based on the use of purple phototrophic bacteria (PPB) in open pond anaerobic photobioreactors as core technology. DEEP PURPLE aims to provide a sustainable supply of biomass and intermediates to be further transformed into bio-products such as slow-release fertilizers, fine chemicals, self-healing building materials and bioplastics for packaging. The DEEP PURPLE photo-biorefinery concept will be upscaled at TRL 7 and validated at two demo sites in Spain.
DEEP PURPLE project proposes an integrated treatment of urban bio waste in a novel multi-platform concept 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 DEEP PURPLE project is based on the combination of optimized upstream and downstream technologies and an innovative wastewater treatment based on the use of purple phototrophic bacteria (PPB) in open pond anaerobic photobioreactors as core technology. DEEP PURPLE aims to provide a sustainable supply of biomass and intermediates to be further transformed into bio-products such as slow-release fertilizers, fine chemicals, self-healing building materials and bioplastics for packaging. The DEEP PURPLE photo-biorefinery concept will be upscaled at TRL 7 and validated at two demo sites in Spain.
The technical work performed in DEEP PURPLE can be divided based on scale: from TRL 4-5 (mainly First Report Period) to TRL 6-7 (Second Report Period)
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:
• Pretreatment: (i) demonstrative plant of thermal hydrolysis with steam explosion in Las Dehesas (Madrid) is providing liquid feedstock to purple phototrophic bacteria-based photobioreactors at WWTP Estiviel (TRL 6), with a yield of 780 L of highly organic-concentrated liquid fraction per 376 kg of OFMSW treated, operating at 150 ºC and 30 mins. (ii) Cellulose recovery plant will be installed at demo site 1 in Q1 2023.
• Conversion: (i) Based on a PPB Multiphysics model, integrated within the DSS, and previous results at TRL5, pilot plant at the DWWTP Estiviel is treating wastewater and the liquid hydrolysate from the OFMSW with biomass productivities of ca. 0.5 Kg of biomass per liter per day. With the contingency plan applied (adding volatile fatty acids at 1 g COD/g COD of liquid hydrolysate), a PHA yield of PPB biomass is above 40% in db. at TRL 6 (the highest reported so far at this scale). In addition, the demonstrative photo-bioreactors at demo site 1 have been constructed and are currently under operation. Previous results at TRL 6 attained discharge limits of the wastewater for total COD, TSS and TP. (ii) Ectoine production at demo scale is under operation with productivities around 1 Kg ectoine per 125 Nm3 of biogas or 258 kg of OFMSW.
• Downstream: (i) 95% pure PHA obtained from biomass, 75% extraction efficiency. (ii) Ectoine recovery yield 67-100%, with salt concentration below 0.14 NaCl. (iii) Extraction and purification of cellulose and saccharification to 2G sugars at TRL7 with 95% theoretical yield. (iv) Transformation of 2G sugars into 1,4 bio-BDO with 100% yield at TRL 7. (v) Transformation of 1,4 bio-BDO into bio-polyesters with chemical properties similar to commercial bio-polyesters. (vi) Production of cellulose nanofibers at pilot scale with interesting characteristics to be used as reinforcement for PHA-based materials. (vii) Production of self-healing concrete with bacterial spores and calcium carbonate. Results at TRL 6 shows that the material can indeed self-healed after a break episode. (viii) Production of pelletized fertilizers from PPB biomass that can improve the pH of the soil and can recover wasted areas.
• Validation and testing: (i) up to 150 kg of PPB biomass were used to formulate and produce pelletized organic fertilizer, which is currently being applied into 3 trials on maize in France, Italy and Spain at TRL 7, which is a pioneer activity in the world.
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:
• Pretreatment: (i) demonstrative plant of thermal hydrolysis with steam explosion in Las Dehesas (Madrid) is providing liquid feedstock to purple phototrophic bacteria-based photobioreactors at WWTP Estiviel (TRL 6), with a yield of 780 L of highly organic-concentrated liquid fraction per 376 kg of OFMSW treated, operating at 150 ºC and 30 mins. (ii) Cellulose recovery plant will be installed at demo site 1 in Q1 2023.
• Conversion: (i) Based on a PPB Multiphysics model, integrated within the DSS, and previous results at TRL5, pilot plant at the DWWTP Estiviel is treating wastewater and the liquid hydrolysate from the OFMSW with biomass productivities of ca. 0.5 Kg of biomass per liter per day. With the contingency plan applied (adding volatile fatty acids at 1 g COD/g COD of liquid hydrolysate), a PHA yield of PPB biomass is above 40% in db. at TRL 6 (the highest reported so far at this scale). In addition, the demonstrative photo-bioreactors at demo site 1 have been constructed and are currently under operation. Previous results at TRL 6 attained discharge limits of the wastewater for total COD, TSS and TP. (ii) Ectoine production at demo scale is under operation with productivities around 1 Kg ectoine per 125 Nm3 of biogas or 258 kg of OFMSW.
• Downstream: (i) 95% pure PHA obtained from biomass, 75% extraction efficiency. (ii) Ectoine recovery yield 67-100%, with salt concentration below 0.14 NaCl. (iii) Extraction and purification of cellulose and saccharification to 2G sugars at TRL7 with 95% theoretical yield. (iv) Transformation of 2G sugars into 1,4 bio-BDO with 100% yield at TRL 7. (v) Transformation of 1,4 bio-BDO into bio-polyesters with chemical properties similar to commercial bio-polyesters. (vi) Production of cellulose nanofibers at pilot scale with interesting characteristics to be used as reinforcement for PHA-based materials. (vii) Production of self-healing concrete with bacterial spores and calcium carbonate. Results at TRL 6 shows that the material can indeed self-healed after a break episode. (viii) Production of pelletized fertilizers from PPB biomass that can improve the pH of the soil and can recover wasted areas.
• Validation and testing: (i) up to 150 kg of PPB biomass were used to formulate and produce pelletized organic fertilizer, which is currently being applied into 3 trials on maize in France, Italy and Spain at TRL 7, which is a pioneer activity in the world.
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.
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.