Using correlation of variables to compare different configurations of microalgae-based wastewater treatment systems

Author(s)

Lima, E. M. M. N. ; Sueitt, A. P. E. ; Daniel, L. A.

• Document type: Journal article
• Source: INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY; v. 21, n. 5, p. 10-pg., 2023-11-05.

Abstract

The performance of three configurations of microalgae-based systems used to treat a nutrient-rich anaerobic effluent was evaluated: a horizontal tubular photobioreactor covered with 40% sunshade mesh (FT); a vertical flat panel photobioreactor covered with 40% sunshade mesh (FPc); and a vertical flat panel photobioreactor directly exposed to solar radiation (FPd). The photobioreactors were inoculated with Chlorella sorokiniana and carbon dioxide (CO2) supplementation was not provided. Physical, chemical and biological characteristics were monitored during a seven-week period. Pairwise correlation of operational parameters was performed to define the easiest way of monitoring treatment systems. Results indicated that the absence of CO2 injection was not a limiting factor for Chlorella sorokiniana growth in any of the tested configurations; however, biomass increase and nutrient removal were negatively influenced by N-nitrite and N-nitrate production. Moreover, direct exposure to solar radiation probably inhibited nitrifying activity in FPd (N-nitrate concentration in this photobioreactor was 80.5% lower than in FPc and 81.8% lower than in FT). Optical density (682 nm) presented a high correlation to microalgae cell counting (R-2 = 0.9063) and total chemical oxygen demand (R-2 = 0.9221), therefore it was indicated as the method of choice to estimate biomass growth. (AU)

• FAPESP's process: 13/50351-4 - Recovering nutrients and carbon from concentrated black water: a sustainable decentralized approach for wastewater treatment
• Grantee: Luiz Antonio Daniel
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/23878-5 - Recovery of nitrogen and phosphorus from wastewater in a combined process UASB and photobioreactor
• Grantee: Luiz Antonio Daniel
• Support Opportunities: Regular Research Grants