Digestate treatment with algae-bacteria consortia: A field pilot-scale experimentation in a sub-optimal climate area. (February 2019)

• Record Type: Journal Article
• Authors: Pizzera, A.; Scaglione, D.; Bellucci, M.; Marazzi, F.; Mezzanotte, V.; Parati, K.; Ficara, E.
• Is Part Of: Bioresource technology. Volume 274(2019)
• Page Start: 232
• Page End: 243
• Publication Date: 2019-02
• Subjects: Digestate -- Nitrogen removal -- Microalgae-bacteria consortium -- Raceway pond -- Nitrification; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2018.11.067
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: Microalgae could grow on nutrients in the liquid fraction of agro-digestate. Microalgae could grow outdoor under sub-optimal climatic conditions for 200 d. Stable nitrification was established and supported by oxygen from photosynthesis. Approximately 7 ± 3% of N was assimilated by microalgae while 61 ± 24% was nitrified. The raceway reactor was slightly more effective than a bubble-column photobioreactor. Abstract: This paper addresses the efficiency of a microalgae-based agricultural digestate treatment at pilot-scale in an outdoor raceway pond (880 L, pH-dependent CO2 dosage) and in a bubble column (74.5 L, air-bubbling). Specifically, nitrogen removal, evolution of the algae-bacteria consortium, and the actual process applicability in the Po Valley climate are discussed. The performance of the two reactors varied seasonally. The average algal productivity in the raceway was 32.4 ± 33.1 mg TSS·L −1 ·d −1 (8.2 ± 8.5 g TSS·m −2 ·d −1 ) while in the PBR it was 25.6 ± 26.8 mg TSS·L −1 ·d −1 ; the average nitrogen removal was 20 ± 29% (maximum 78%) and 22 ± 29% (maximum 71%) in the raceway and in the column, respectively. Nevertheless, nitrification had a key role as 61 ± 24% and 52 ± 32% of the nitrogen load was oxidized in the raceway and in the column, respectively.