Browsing by resource type "bachelor thesis"
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- Resíduo do processamento da castanha como fonte energéticaPublication . Moreira, Joana T. de Magalhães; Serralha, Fátima; Marques, Isabel Paula Ramos; Eusébio, AnaABSTRACT: This work was carried out to study the application of mesophilic anaerobic digestion (AD) in chestnut shell residues, using different pre-treatments. Physio-chemical and biological characterization of the residue of the chestnut shell were realized, with and without pre-treatment. In order to control and study the AD process, several analytical methods were realized such as: pH, chemical oxygen demand, total solids, volatile solids, total nitrogen and ammonia nitrogen. Chemical composition of the residue and the pre-treated by Quantitative Acid Hydrolysis (QAH) was also performed. The residue was submitted to a mechanical pre-treatment by grinding to a size of 0,5 mm. Then, three pre-treatments were tested: (1) the physical-chemical, with association of temperature and pressure (autoclave) with an acid chemical agent (H2SO4); (2) the thermal, with the use of heating associated with the presence of an alkaline agent (NaOH); and (3) the physical method, with the use of microwaves associated to the presence of an alkaline agent (NaOH). A control assay was also carried out, where the residues were triturated but not pre-treated. The highest biogas production, with a value of about 30 mL, was obtained after 14 days from the residue samples of chestnut shell pre-treated with NaOH. The highest gas yield - 7.66 ± 1.60 mL/g initial biogas Volatile Solids and 2.47 ± 0.00 mL/g initial methane Volatile Solids - was also recorded in the NaOH pretreated residue. It was concluded that alkaline pretreatment was the most efficient in terms of effect on the anaerobic digestion process.