Conventional activated sludge vs. photo-sequencing batch reactor for enhanced nitrogen removal in municipal wastewater: Microalgal-bacterial consortium and pathogenic load insights

Elisa Clagnan; Serena Petrini; Silvia Pioli; Federica Piergiacomo; Atif Aziz Chowdhury; Lorenzo Brusetti; Paola Foladori

doi:10.1016/j.biortech.2024.130735

Conventional activated sludge vs. photo-sequencing batch reactor for enhanced nitrogen removal in municipal wastewater: Microalgal-bacterial consortium and pathogenic load insights

Bioresour Technol. 2024 Apr 24:401:130735. doi: 10.1016/j.biortech.2024.130735. Online ahead of print.

Authors

Elisa Clagnan¹, Serena Petrini², Silvia Pioli³, Federica Piergiacomo⁴, Atif Aziz Chowdhury⁴, Lorenzo Brusetti⁵, Paola Foladori²

Affiliations

¹ Free University of Bolzano, Faculty of Science and Technology, Piazza Università 1, 39100 Bolzano, Italy; Department for Sustainability, Biotechnologies and Agroindustry Division, ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Casaccia Research Center, Via Anguillarese 301 00123 Rome, Italy; Gruppo Ricicla Labs, Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia (DiSAA), Università Degli Studi di Milano, Via Celoria 2 20133 Milano, Italy.
² University of Trento, Department of Civil, Environmental and Mechanical Engineering, Via Mesiano 77 38123, Trento, Italy.
³ Free University of Bolzano, Faculty of Science and Technology, Piazza Università 1, 39100 Bolzano, Italy; Institute of Research on Terrestrial Ecosystems (IRET), National Research Council (CNR), Monterotondo Scalo RM, Italy.
⁴ Free University of Bolzano, Faculty of Science and Technology, Piazza Università 1, 39100 Bolzano, Italy.
⁵ Free University of Bolzano, Faculty of Science and Technology, Piazza Università 1, 39100 Bolzano, Italy. Electronic address: Lorenzo.Brusetti@unibz.it.

PMID: 38670293
DOI: 10.1016/j.biortech.2024.130735

Abstract

Municipal wastewater treatment plants are mostly based on traditional activated sludge (AS) processes. These systems are characterised by major drawbacks: high energy consumption, large amount of excess sludge and high greenhouse gases emissions. Treatment through microalgal-bacterial consortia (MBC) is an alternative and promising solution thanks to lower energy consumption and emissions, biomass production and water sanitation. Here, microbial difference between a traditional anaerobic sludge (AS) and a consortium-based system (photo-sequencing batch reactor (PSBR)) with the same wastewater inlet were characterised through shotgun metagenomics. Stable nitrification was achieved in the PSBR ensuring ammonium removal > 95 % and significant total nitrogen removal thanks to larger flocs enhancing denitrification. The new system showed enhanced pathogen removal, a higher abundance of photosynthetic and denitrifying microorganisms with a reduced emissions potential identifying this novel PSBR as an effective alternative to AS.

Keywords: Conventional biological treatment; Microalgae; Nitrogen removal; Photobioreactors; Shotgun metagenomic analysis; Wastewater.