Work

Indigenous microalgae consortium for producing safe reclaimed water and bio-fertilisers. Batch tests for replication, scale-up and legislative analysis

Year: 2025

Type: article

Abstract: This study aimed to assess the potential of using indigenous microalgae to treat sewage and produce safe reclaimed water and bio-fertilisers. Cultivation tests were conducted using sole or mixed sewage streams combining primary effluent (PSE), secondary effluent (SSE), and centrate (CEN) to identify the most suitable substrate. Overall, higher nitrogen removal rates, biomass productivity, and carbon biofixation were observed when microalgae were cultivated in PSE compared to SSE, with values ranging from 2.1 to 12.1 mgN·L −1 ·d −1 , 18 to 52 mgVSS·L −1 ·d −1 (20–53 mgTSS·L −1 ·d −1 ), and 10.7 to 27.0 mgCO 2 ·L −1 ·d −1 , respectively. Adding centrate improved microalgae performance by increasing the availability of nutrients and inorganic carbon, but when 30 % centrate was added, detrimental effects were observed. The costs of the microalgae-based treatment process ranged from 0.081 to 0.098 €·m −3 , which is significantly lower than those of conventional activated sludge (CAS) processes. The reclaimed water obtained during the tests demonstrated high-quality in terms of pathogen and metal levels, making it suitable (in Spain) for agricultural, recreational, industrial and environmental uses. However, some legal gaps were identified regarding the use of reclaimed water and microalgae biomass for bio-fertiliser production. • Primary effluent demonstrated higher productivity compared to secondary effluent. • Centrate addition at proportion < 30 % increased nutrient concentrations. • Process costs ranged 0.081 to 0.098 €·m −3 offering a cost-effective alternative. • Reclaimed water was suitable for agricultural, industrial and other uses. • Findings contribute to addressing legal barriers in utilising algae as fertilisers.

Source: Algal Research

DOI: 10.1016/j.algal.2025.104043

Authors: J. González-Camejo, A.L. Eusebi, F. Fatone, M. Pachés

Institutions: Universitat de Vic - Universitat Central de Catalunya, Marche Polytechnic University, Universitat Politècnica de València

Language: English

Topic: Algal biology and biofuel production

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

SDGs: Clean water and sanitation, Responsible consumption and production, Zero hunger

Open Access status: hybrid

Estimated APC paid: $4,190