Treatment of biodigested coffee processing wastewater using Fenton's oxidation and coagulation/flocculation.

Autor: Gomes de Barros V; Laboratório de Saneamento Ambiental, Departamento de Engenharia Rural, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, UNESP, Câmpus de Jaboticabal, Av. Prof. Paulo Donato Castallene, Km 5, 14884-900, Jaboticabal, SP, Brazil; Programa de Pós-Graduação em Microbiologia Agropecuária, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (UNESP), Campus de Jaboticabal, Jaboticabal, SP, Brazil., Rodrigues CSD; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal. Electronic address: csdr@fe.up.pt., Botello-Suárez WA; Laboratório de Saneamento Ambiental, Departamento de Engenharia Rural, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, UNESP, Câmpus de Jaboticabal, Av. Prof. Paulo Donato Castallene, Km 5, 14884-900, Jaboticabal, SP, Brazil; Programa de Pós-Graduação em Microbiologia Agropecuária, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (UNESP), Campus de Jaboticabal, Jaboticabal, SP, Brazil., Duda RM; Laboratório de Saneamento Ambiental, Departamento de Engenharia Rural, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, UNESP, Câmpus de Jaboticabal, Av. Prof. Paulo Donato Castallene, Km 5, 14884-900, Jaboticabal, SP, Brazil; Faculdade de Tecnologia de Jaboticabal, 'Nilo Stéfani', Av. Eduardo Zambianchi, 31, 14883-130, Vila Industrial, Jaboticabal, São Paulo, Brazil., Alves de Oliveira R; Laboratório de Saneamento Ambiental, Departamento de Engenharia Rural, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, UNESP, Câmpus de Jaboticabal, Av. Prof. Paulo Donato Castallene, Km 5, 14884-900, Jaboticabal, SP, Brazil., da Silva ES; Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal., Faria JL; Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal., Boaventura RAR; Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal., Madeira LM; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
Jazyk: angličtina
Zdroj: Environmental pollution (Barking, Essex : 1987) [Environ Pollut] 2020 Apr; Vol. 259, pp. 113796. Date of Electronic Publication: 2019 Dec 13.
DOI: 10.1016/j.envpol.2019.113796
Abstrakt: Biodigested coffee processing wastewater (CPW) presents a high organic load and does not meet the limits imposed by legislation (namely in Brazil) for discharge into water bodies. Anaerobic digestion generally cannot provide a satisfactory organic matter reduction in CPW as a significant fraction of recalcitrant compounds still persists in the treated effluent. So, this study aims to find alternative ways to remove refractory organic compounds from this wastewater in order to improve the biodegradability and reduce the toxicity, which will allow its recirculation back into the anaerobic digester. Three treatment approaches (Fenton's oxidation - Approach 1, Coagulation/flocculation (C/F) - Approach 2, and the combination of C/F with Fenton's process - Approach 3) were selected to be applied to the biodigested CPW in order to achieve that objective. The application of the Fenton process under the optimal operating conditions (initial pH = 5.0; T = 55 °C, [Fe 3+ ] = 1.8 g L -1 and [H 2 O 2 ] = 9.0 g L -1 ) increased the biodegradability (the BOD 5 :COD ratio raised from 0.34 ± 0.02 in biodigested CPW to 0.44 ± 0.01 after treatment) and eliminated the toxicity (0.0% of Vibrio fischeri inhibition) along with moderate removals of organic matter (51.3%, 55.7% and 39.7% for total organic carbon - TOC, chemical oxygen demand - COD and biochemical oxygen demand - BOD 5 , respectively). The implementation of a coagulation/flocculation process upstream from Fenton's oxidation, under the best operating conditions (pH 10-11 and [Fe 3+ ] = 250 mg L -1 ), also allowed to slightly increase the biodegradability (from 0.34 to 0.47) and reduce the toxicity, whereas providing a higher removal of organic matter (TOC = 76.2%, COD = 76.5 and BOD 5  = 66.3% for both processes together). Approach 1 and Approach 3 showed to be the best ones, implying similar operating costs (∼74 R$ m -3 /∼17 € m -3 ) and constitute an attractive option for managing biodigested CPW.
Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest regarding the publication of this article.
(Copyright © 2019 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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