ALGALVANISE · ALGAL biorefinery of biogas digestate to high VAlue fuNctional IngredientS through circular approachEs
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2020-04-01 → 2022-03-31
- EU contribution
- €184,591
- Participants
- 1
- Scheme
- MSCA-IF
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Results in brief
ALGAL biorefinery of biogas digestate to high VAlue fuNctional IngredientS through circular approachEs
ALGALVANISE was aimed at addressing the challenges associated with digestate originating from anaerobic digestion (AD) plants. A major problem with digestates comes from their high phosphorous contents which can lead to eutrophication issues in areas with a large number of anaerobic digesters. Hence, often digestate has to be treated for disposal causing further environmental and economic challenges for AD plant operators. ALGALVANISE considers this phosphorus as a source of nutrients, using microalgae as a tool for phosphate recovery, while addressing the challenges associated with high upstream and downstream costs of microalgae cultivation. The effluent stream of high-rate anaerobic digestion systems that treat dairy process water (DPW) waste and the digestate from an anaerobic digestion facility that treats municipal solid waste (MSW digestate) were used to study the potential of biogas-microalgae integrated biorefineries. In order to understand the feasibility of this biorefinery, the work is divided into the following specific objectives: 1) Identification and selection of algal strains capable of yielding high biomass with efficient nutrient recovery. 2) Optimised process conditions for luxurious uptake of nutrients by selected algal strain in untreated digestate with the use of minimum quantities of enzymes. 3) Determination of minimum chitosan dosage to enhance bacterial flocculation in terms of yield and quality of the biomass without using any alkali agents. 4) Profile of algal chemical composition and the properties of the products (lipids, proteins, carbohydrates, pigments) produced and harvested under different process conditions. 5) Predictive models developed from large sets of lab-scale experimental and pilot-scale operational data that are used to relate process conditions and variations in digestate composition with yields and quality of the algae. The two years project has resulted in some significant outcomes that might make the biogas-microalgae biorefinery a possibility in the near future. Enzymes are efficient in treating the digestate to increase the transparency of the digestate for efficient light penetration for microalgae cultivation. The mixed algal culture of Scendesmus and Hematococcus species grow efficiently in both MSW (enzyme-treated) and DPW digestates and produce valuable compounds such as astaxanthin in high concentrations. The cultivation is mixotrophic with no additional supplementation of nutrients which significantly bring down the production costs. The mixed culture can be flocculated using natural flocculating agents which makes the downstream processing quite efficient compared to conventional membranes and centrifuges.
Data: CORDIS, © European Union
Project objective
The anaerobic digestion (AD) industry is currently facing serious environmental and economic challenges due to the restrictions on the usage of digestate (the slurry residue of the process), coupled with reductions in subsidies for biogas production. It is important for the biogas industry to shift towards an AD biorefinery approach to make valuable co-products from the digestate fraction while recovering nutrients. Algae is an efficient tool for recovering the nutrients due to its ability to assimilate the nutrients efficiently while producing biomass rich in proteins, lipids, carbohydrates, vitamins, and minerals. However, there are no relevant commercially-operating algal digestate treatment plants due to the high energy inputs required for producing and harvesting the algae. ALGALVANISE will advance the state-of-the art by developing two novel concepts: 1) enzyme-assisted enhanced algal cultivation; and 2) combinatorial bioflocculation using bacteria and biopolymers. These two processes are targeted towards efficient nutrient recovery by algae from the digestate and harvesting high-quality algal biomass to produce high-value functional ingredients. The proposed body of research involves extensive training of the hosted researcher in the development of skills that will have a clear positive impact regarding her professional development and career opportunities. It is expected that ALGALVANISE will enable the Researcher to progress significantly with regards to her career goals, a primary one regards being an independent researcher that can develop commercially-relevant high-impact research projects that develop and demonstrate innovations that can ultimately be deployed at flagship facilities. The innovations developed in ALGALVANISE could themselves ultimately lead to a flagship AD-algal biorefinery or they could develop the Researcher’s skills to such a degree that she could lead flagship projects, based on other technologies, in the future.
Original text from CORDIS.
Participants
- CELIGNIS LIMITED · LimerickCoordinatorIreland
Links
Data: CORDIS, © European Union