Combined system for wastewater treatment: ozonization and coagulation via tannin-based agent for harvesting microalgae by dissolved air flotation. Issue 9 (16th April 2022)

• Record Type: Journal Article
• Authors: Oliveira, Gislayne Alves; Machado, Ênio Leandro; Knoll, Rhauani Segatto; Dell'Osbel, Naira; Colares, Gustavo Stolzenberg; Rodrigues, Lúcia Ribeiro
• Is Part Of: Environmental technology. Volume 43:Issue 9(2022)
• Page Start: 1370
• Page End: 1380
• Publication Date: 2022-04-16
• Subjects: Microalgae harvesting -- eutrophication -- Venturi tube -- tannin-based coagulant -- wastewater treatment -- integrated system; Environmental engineering -- Periodicals; Environmental protection -- Periodicals; 628.05
• DOI: 10.1080/09593330.2020.1830181
• Languages: English
• ISSNs: 0959-3330

Abstract

ABSTRACT: This study evaluated the performance of urban wastewater treatment in pilot-plant by an integrated system consisting of anaerobic reactor, microalgae cultivation, Venturi tube ozone recirculation, coagulation/flocculation with tannin-based agent natural coagulant, and dissolved air flotation (DAF). Ozone concentrations (without ozone, 0.13 and 0.25 mg O3 /mg of biomass) and tannin dosages (65, 85 and 105 mg/L) were evaluated regarding microalgae separation and their influences on wastewater treatment performance. During the experiments, it was verified that the treatment efficiency increased when ozone was applied and with higher tannin dosages. The best results were found with 0.13 mg O3 /mg of biomass and 105 mg/L of tannin, obtaining excellent removal of turbidity removal (99.4%), apparent colour at 420 nm (94.5%), TN (83.2%), N-NH3 (100%), TOC (86.8%), BOD5 (86.5%) and COD (100%), 47.6% reduction in electric conductivity, 46.1% in TDS, 66.4% TP removal for the integrated system and 84% microalgae biomass recovery were obtained. Our results showed that the system proved to be a viable alternative for the treatment of urban wastewater and the recovery of microalgae through the insertion of ozone via Venturi tube combined with tannin-based agent. GRAPHICAL ABSTRACT: UF0001