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The Anaerobic Sequencing Batch Reactor (ASBR) operates by sequential batches, has been studied as an alternative treatment for different systems because of their versatility. The ASBR is applicable for the conversion of a wide variety of organic wastewaters to methane and carbon dioxide (biogas). The main factors affecting the overall performance of the ASBR are: agitation, Substrate/Biomass ratio, geometric configuration of the reactor and the feeding strategy. In this research the strategy agitation was carried out by used of a gaslift system coupled to an ASBR. The aim of the research was the creation of bases for the design and process control of an Anaerobic Sequencing Batch Gaslift Reactor on a laboratory scale in order to find the optimal operating regime and optimize the process. The type of gaslift system to be used is an internal loop with a concentric draught tube configuration, which enables the gas may be sparged either the draught tube or the annulus. The simple design of a gas lift reactor permits less expensive operation, requires less maintenance, low investment costs, low interference and low power consumption.
Scientific and technical objectives of the research include the analysis of macro geometric dimensions of the reactor, developing innovative solutions for optimization of mixing process (gaslift mixing), analysis of the hydrodynamics and the homogenization inside of the reactor.
This study also includes the flow determination in the riser, the evaluation of the liquid circulation velocity in the downcomer and the influence of the vertical draft tube and the effect of top and bottom clearance. Also, the goal was to find an adequate mixture to not destroy microorganisms but to allow the sedimented biomass and undigested solids may rise quickly and mixed with the feed substrate.
Regular electricity access is a key element for the economic development and social welfare of rural areas. Decentralized energy generation has the advantage of using local resources, increasing employment and reducing transmission and distribution losses. Brazil is a tropical country, endowed with vast arable land, plentiful precipitation levels, and a large supply of human labour. Furthermore, it has strong regional distinctions with geographical, cultural and economical differences. Forestry and agriculture, important activities in the Brazilian economy, are dependent on local people and are deeply connected to traditions, nature and culture. Furthermore, these activities generate a significant amount of residues that could be used in conversion technologies for biomass, based on type, availability and market demand. When biomass were used to generate energy locally, community members could have business opportunities, improving local economy and life quality of individuals while diversifying the Brazilian energy matrix, which is mostly based on hydropower. Alternatives for implementing small-scale decentralized biomass schemes are dependent on the screening of the existing biomass supply chains, the implementation of adapted technologies for local conditions and the exploration of local resources. The present research carried out a detailed field work in order to evaluate the potential of Brazilian biomass in different regions. The author identified crucial needs, usual constraints and possible challenges of rural electrification and economic development in Brazil. Several case studies and social groups were investigated in the Federal States of Minas Gerais, São Paulo and Pará to identify different resource management strategies, which biomass technology was applied and the needs of the local population. It was concluded that the compaction of biomass to generate solid biofuels with uniform properties could be a cost-effective alternative for communities taking advantage of the resources available in the region to produce energy. Nevertheless, each case has to be considered on its own. It was concluded that energy supply and consumption should be addressed through integrated research. Scientific research should be focused on technological solutions for improving living standards and socio-economic development in rural areas. The implementation of new regulatory arrangements and a constant revision of the Brazilian energy policies are crucial for encouraging a national industry for renewables. It was also concluded that the cultural, geographical and socio-economic discrepancies of Brazil could involve challenges for the implementation of future projects, even when their development would provide benefits for Brazil as a whole.