title: Reuse of microalgae grown in full-scale wastewater treatment ponds: Thermochemical pretreatment and biogas production.
abstract: This study assessed thermochemical pretreatment of microalgae harvested from a full-scale wastewater treatment pond prior to its anaerobic digestion using acid and alkaline chemical doses combined with thermal pretreatment at 80°C. Results indicated that alkaline and thermal pretreatment contributed mostly to glycoprotein and pectin solubilisation; whilst acid pretreatment solubilised mostly hemicellulose, with lower effectiveness for proteins. Regarding the anaerobic biodegradability, biochemical methane potential (BMP) tests showed that final methane yield was enhanced after almost all pretreatment conditions when compared to non-pretreated microalgae, with the highest increase for thermochemical pretreatment at the lowest dose (0.5%), i.e. 82% and 86% increase for alkaline and acid, respectively. At higher doses, salt toxicity was revealed by K(+) concentrations over 5000mg/L. All BMP data from pretreated biomass was successfully described by the modified Gompertz model and optimal condition (thermochemical 0.5% HCl) showed an increase in final methane yield and the process kinetics.
authors.affiliation: Environmental and Chemical Technology Group, Department of Chemistry, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, Minas Gerais, Brazil. Electronic address: fabianapassos@ufop.br.
authors.forename: Fabiana
authors.initials: F
authors.lastname: Passos
authors.affiliation: Environmental and Chemical Technology Group, Department of Chemistry, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, Minas Gerais, Brazil.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Felix
authors.affiliation: Environmental and Chemical Technology Group, Department of Chemistry, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, Minas Gerais, Brazil.
authors.forename: Hemyle
authors.initials: H
authors.lastname: Rocha
authors.affiliation: Technology in Civil Engineering Department, Universidade Federal de São João del-Rei, Campus Alto Paraopeba, 36420-000 Ouro Branco, Minas Gerais, Brazil.
authors.forename: Jackson de Oliveira
authors.initials: Jde O
authors.lastname: Pereira
authors.affiliation: Environmental and Chemical Technology Group, Department of Chemistry, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto, Minas Gerais, Brazil.
authors.forename: Sérgio
authors.initials: S
authors.lastname: de Aquino
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D056804:Biofuels / Q000032:analysis*; D018533:Biomass; D008697:Methane / Q000096:biosynthesis; D058086:Microalgae / Q000254:growth & development* / Q000378:metabolism; D009930:Organic Chemicals / Q000032:analysis; D061005:Ponds / Q000382:microbiology*; D011188:Potassium / Q000032:analysis; D012965:Sodium Chloride / Q000633:toxicity; D012995:Solubility; D013696:Temperature; D062065:Wastewater / Q000382:microbiology*; D018508:Water Purification / Q000379:methods*
chemical_list: D056804:Biofuels; D008697:Methane; D009930:Organic Chemicals; D011188:Potassium; D012965:Sodium Chloride; D062065:Wastewater
keywords: Algae; Anaerobic digestion; Inhibition; Methane; Modelling