Solubilização de matéria orgânica e nutrientes do lodo algáceo de uma lagoa de estabilização através de processos hidrolíticos alcalino e térmico
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Data
2017-03-23
Autores
Lamberti, Gisele Gavazza
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Universidade Federal do Espírito Santo
Resumo
Aiming to optimize the algal biomass biodegradability during anaerobic digestion, several hydrolysis processes havebeen studied, promoting increaseofenergy production by the hydrolysis of algaecellsand subproducts generation.This research has the proposeto performthermal and alkaline pretreatmentof the algae biomass in order to increase the algae biodegradability in the anaerobic digestion process through the organic carbon, nitrogen and phosphorussolubilization. Thisproject is part of the energy efficiency analysis of a wastewater treatment plant located in Vila Velha-ES, aiming to reduce the demand ofenergy during the treatment processes. The mixotrophic algal sludge collected for this research presented a total solids concentration of 35.1 g / L, which were analyzed for organic matter solubilization (CODs),nutrients and exopolymers. For this research, thermal hydrolysis at 90 ° C solubilized19% of CODs,while in the alkaline process at pH 12, itincreasesto21%.There was increasing solubilization of carbohydrates with the increase of temperaturein thermal pretreatment, but the same pattern was not observed during the alkaline pretreatment. The color of the biomass changed from green to brown during the treatments, which suggests that Maillard reactions occurred during the reaction time, with interactionsbetweencarbohydrates andsoluble proteins.A reduction ofsoluble phosphate concentration in the sample along the pretreatmentwas identified, suggestingthe precipitation of these with other cations such as Ca2+ and Mg2+, leading to the precipitation of hydroxyapatite and struvite compounds. In this way, both pretreatmentsshowed satisfactory results regarding the solubilization of organic material, nutrients, carbohydrates and proteins. Although the alkaline pretreatmentindicatedbetter results in the solubilization of organic mattter, for the general purpose of this research, thermal processes were more efficient in promoting a better solubilization of other compounds such as nutrients, carbohydrates and proteins.
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Microalgae , Pretreatment , Biodegradability , Microalgas , Processos Hidrolíticos , Biodegradabilidade