Microalgae-bacteria consortia in high-rate ponds for treating urban wastewater: Elucidating the key state indicators under dynamic conditions. (1st May 2020)

• Record Type: Journal Article
• Authors: Robles, Ángel; Capson-Tojo, Gabriel; Galès, Amandine; Ruano, María Victoria; Sialve, Bruno; Ferrer, José; Steyer, Jean-Philippe
• Is Part Of: Journal of environmental management. Volume 261(2020)
• Publication Date: 2020-05-01
• Subjects: Open ponds -- Domestic wastewater -- Monitoring -- Single-stage treatment; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2020.110244
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: On-line performance indicators of a microalgae-bacteria consortium were screened out from different variables based on pH and dissolved oxygen on-line measurements via multivariate projection analysis, aiming at finding on-line key state indicators to easily monitor the process. To fulfil this objective, a pilot-scale high-rate pond for urban wastewater treatment was evaluated under highly variable conditions, i.e. during the start-up period. The system was started-up without seed of either bacterial or microalgal biomass. It took around 19 days to fully develop a microalgal community assimilating nutrients significantly. Slight increases in the biomass productivities in days 26–30 suggest that the minimum time for establishing a performant bacteria-microalgae consortium could be of around one month for non-inoculated systems. At this point, the process was fully functional, meeting the European discharge limits for protected areas. The results of the statistical analyses show that both the pH and the dissolved oxygen concentration represent accurately the biochemical processes taking place under the start-up of the process. Both pH and dissolved oxygen represented accurately also the performance of the high-rate algal pond, being affordable, easily-implemented, options for monitoring, control and optimization of industrial-scale processes. Graphical abstract: Image 1 Highlights: A stable functional bacterial community was stablished in less than 10 days. It took 19 days to develop a microalgal community assimilating nutrients. pH and DO derived variables reproduce the strong dynamics of the process. On-line key state indicators that are easily measured were found.