Journal Article Epublish 10 citations
PubMed: 38163195 DOI: 10.1016/j.heliyon.2023.e23240
Integrating microalgae growth in biomethane plants: Process design, modelling, and cost evaluation.
Heliyon 10(1):e23240
Authors: Simone Rossi, Davide Carecci, Francesca Marazzi, Francesca Di Benedetto, Valeria Mezzanotte, Katia Parati, Davide Alberti, Ignazio Geraci, Elena Ficara
Affiliations
- Politecnico di Milano, DICA - Department of Civil and Environmental Engineering, 2, P.zza Leonardo da Vinci, 20133 Milano, Italy.
- University of Milano - Bicocca, DISAT - Department of Earth and Environmental Sciences, 1, P.zza della Scienza, 20126 Milano, Italy.
- Istituto Sperimentale Italiano Lazzaro Spallanzani, Aquaculture division, 26027 Rivolta d'Adda, Italy.
- A2A s.p.a. 230, v. Lamarmora, 25124, Brescia, Italy.
Abstract
The integration of microalgae cultivation in anaerobic digestion (AD) plants can take advantage of relevant nutrients (ammonium and ortho-phosphate) and CO loads. The proposed scheme of microalgae integration in existing biogas plants aims at producing approximately 250 t·y of microalgal biomass, targeting the biostimulants market that is currently under rapid expansion. A full-scale biorefinery was designed to treat 50 kt·y of raw liquid digestate from AD and 0.45 kt·y of CO from biogas upgrading, and 0.40 kt·y of sugar-rich solid by-products from a local confectionery industry. An innovative three-stage cultivation process was designed, modelled, and verified, including: i) microalgae inoculation in tubular PBRs to select the desired algal strains, ii) microalgae cultivation in raceway ponds under greenhouses, and iii) heterotrophic microalgae cultivation in fermenters. A detailed economic assessment of the proposed biorefinery allowed to compute a biomass production cost of 2.8 ± 0.3 €·kg DW, that is compatible with current downstream process costs to produce biostimulants, suggesting that the proposed nutrient recovery route is feasible from the technical and economic perspective. Based on the case study analysis, a discussion of process, bioproducts and policy barriers that currently hinder the development of microalgae-based biorefineries is presented.
MeSH
Growth, Biomass, Microalgae, Nutrients