Browsing by Author "Silva, Maria Elisabete"
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- Anaerobic Digestion Sludge Composting - Assessment of the Star-up processPublication . Silva, Maria Elisabete; Araújo, Sara; Brás, Isabel; Cunha-Queda, Ana Cristina; Nunes, Olga CristinaThe aim of this work was to follow the start-up of the composting process of sludge from the anaerobic digestion of municipal solid waste and to assess the quality of the final product. The temperature profile and dry matter content was registered over 10 weeks. The composting process was monitored by standard physical and chemical parameters and the quality of the final compost was assessed by phytotoxicity and stability assays. The low average temperature values registered during composting suggest over aeration. In addition, all the standard physical and chemical parameters analysed showed slight variations over composting, suggesting that the anaerobic digestion sludge was already a stable raw material. The final compost was not phytotoxic and was stable, but contained some inert materials. Overall, the final compost had quality compatible to be used as soil amendment. Nevertheless, the operational conditions optimization should be carried out to improve its quality
- Anaerobic digestion sludge compsoting - assessment of the star-up processPublication . Silva, Maria Elisabete; Araújo, Sara; Brás, Isabel; Cunha-Queda, Ana Cristina; Nunes, Olga Cristina; Lobo, G.; Cordeiro, A.; Faria, M.The aim of this work was to follow the start-up of the composting process of sludge from the anaerobic digestion of municipal solid waste and to assess the quality of the final product. The temperature profile and dry matter content was registered over 10 weeks. The composting process was monitored by standard physical and chemical parameters and the quality of the final compost was assessed by phytotoxicity and stability assays. The low average temperature values registered during composting suggest over aeration. In addition, all the standard physical and chemical parameters analysed showed slight variations over composting, suggesting that the anaerobic digestion sludge was already a stable raw material. The final compost was not phytotoxic and was stable, but contained some inert materials. Overall, the final compost had quality compatible to be used as soil amendment. Nevertheless, the operational conditions optimization should be carried out to improve its quality.
- Overview of one operation and control manual of anaerobic digestersPublication . Silva, Maria Elisabete; Ferreira, Joana; Antunes, Pedro BailaThe present work has intendent to describe one “Operational and control manual of the anaerobic digesters (AD)” in order to comply all of the operational and control issues that may be useful for the AD technical staff. The wastes characteristics (e.g. the difficult handling, wide qualitative variety, low biodegradability and toxic contaminants), the heavy infrastructures and equipment, and above all the biochemical specificities of the process contribute to the complexity of the anaerobic digestion process. All of these issues are explaining in this manual in a simply way to be practical to the technical staff.
- Potential production of RDF from municipal solid waste mechanical treatment and selective collection rejected streamsPublication . Duarte, Diana; Silva, Maria Elisabete; Lemos, Luís Teixeira de; Brás, IsabelIn order to fulfill legal requirements, adequate alternatives to traditional municipal waste landfilling must be found. The valorization of some residual streams from municipal solid waste (MSW) treatment plants are among them. The purpose of this study is to characterize the rejected streams resulting from the mechanical treatment of municipal solid waste and from the yellow waste container selective collection, in order to evaluate the potential of their valorization as Refuse Derived Fuel (RDF). To accomplish this purpose, two sampling campaigns were done. Physical characteristics, proximate analysis, heating value and chlorine content were determined. As expected, results show that the refused stream from mechanical treatment and from the selective collection are rather different in overall composition, water content, energetic matter and ashes, as well as heating value and chlorine, with the last showing higher calorific value and lower moisture, therefore superior energy recovery availability. Preliminary data allows us to conclude that studied materials have a very interesting potential to be used as RDF.
- Refuse Derived Fuel from Municipal Solid Waste Rejected Fractions - A case StudyPublication . Brás, Isabel; Silva, Maria Elisabete; Lobo, Germana; Cordeiro, Ana; Faria, Miguel; Lemos, Luís Teixeira dePortuguese legislation enforces adequate alternatives to municipal waste landfilling of organic wastes as well as others susceptible of valorisation. In the present work, the energetic valorisation of final municipal solid wastes rejected fractions is studied through the production of Refuse Derived Fuel (RDF). To accomplish this purpose several sampling campaigns were performed. Physical, chemical and energetic characterization of the rejected streams was done. Preliminary data allows us to conclude that studied materials have interesting potential to be used as RDF, particularly if blended with higher heating value materials in order to obtain RDF pellets with good combustion behavior, consistency and storage characteristics.
- Refuse Derived Fuel from Municipal Solid Waste rejected fractions- a Case StudyPublication . Brás, Isabel; Silva, Maria Elisabete; Lobo, Germana; Cordeiro, Ana; Faria, Miguel; Lemos, Luís Teixeira deMunicipal Solid Wastes (MSW) that contain mixtures of paper, wood, green wastes, food wastes, plastics, leather, and rubber can have energy characteristics similar to wood. Use of MSW as a fuel can be accomplished by burning the as-received material, called mass burning, but processing is often required before it can be burned effectively. The purpose is to reduce size and remove materials, valuable materials or non-combustible materials in order to be reclaimed and used as alternative fuel for sustainable disposal and converted into green and clean energy. The impact of burning these heterogeneous materials in traditional boiling systems, as primary or supplemental fuel, needs to be assessed: the physical and chemical characterization of raw materials should be performed. According to Portuguese Standard NP 4486:2008, a classification system is used based on Refuse Derived Fuel (RDF) main parameters: lower heating value, chlorine and mercury content. Higher heating value is in fact associated with paper/card, plastics, wood and textiles content and, once these materials have in their composition biogenic compounds (40-80% w/w), they become an interesting alternative fuel to accomplish the reduction of CO2 emissions.
- Valorization of beer brewing wastes by compostingPublication . Silva, Maria Elisabete; Brás, IsabelThe aim of this work was to study the viability of recycling the residual yeast and diatomaceous earth (RYDE) slurry generated by the beer brewing industry by composting with animal manures, as well as to evaluate the quality of the composts obtained. Two pilot composting trials were carried out with different mixes: cow manure/RYDE slurry (Pile CM) and sheep manure/RYDE slurry (Pile SM). For all piles, wood chips were applied as bulking agent. The process was monitored by evaluating standard physical and chemical parameters. The compost quality was assessed by the heavy metals content and phytotoxicity. Both piles reached a thermophilic phase in the first day, however having different trends. The pH showed a slight alkaline character. The C/N reached values lower than 19 at the end of composting process. Generally, all the piles exhibited absence of heavy metals. However, the pile SM exhibited phytotoxicity. This study showed that RYDE slurry can be valorized by composting with cow manure