ABSTRACT
RESUMO A quantificação de biomassa fixa em reatores de leito móvel com biofilme (MBBRs) é essencial para avaliação e controle do desempenho deles. Entretanto, observa-se que tal quantificação é realizada empregando-se diversas técnicas, o que dificulta comparações entre resultados. No presente trabalho, foram testadas duas das principais técnicas (agitação mecânica e ultrassom) utilizadas para extração de biomassa aderida aos meios-suporte (mídias) de um MBBR sem utilização de agentes químicos. Os desenhos experimentais foram realizados utilizando-se planejamento fatorial completo, e, para tal, foram selecionadas duas variáveis independentes: tempo (T) de exposição de 15 a 60 min; e volume de água destilada utilizado para extração (V) de 100 a 400 mL. O ultrassom mostrou-se superior à agitação mecânica quanto à eficiência no percentual extraído de sólidos suspensos totais (%SST), e embora nenhuma das variáveis (T ou V) tenha contribuído significativamente nas faixas testadas, com base na superfície de respostas, foi conduzido um novo experimento, ampliando a faixa de T de 5 a 90 min. A variável T contribuiu significativamente para o %SST, e o melhor resultado foi obtido com T = 90 min. Recomenda-se o uso de ultrassom, volume de mais fácil manuseio (250 mL) e T = 90 min. Ensaios adicionais são recomendados, tendo em vista a padronização do método.
ABSTRACT Quantification of attached biomass in Moving Bed Biofilm Reactors (MBBR) is essential for performance assessment and process control. However, it is observed that such quantification is performed using the most diverse techniques, which hampers comparisons between results. In this investigation, two of the main techniques used (mechanical agitation and ultrasound) were compared for removal of the biomass attached to the support media of an MBBR reactor without the use of chemical agents. The experiments were planned following full factorial designs using the two independent variables: Exposure time (T) from 15 to 60 min; and Volume of distillate water used for extraction (V) from 100 to 400 mL. The results revealed that ultrasound is superior to mechanical agitation regarding detachment of the total suspended solids (%TSS) and though neither T or V contributed significantly within the interval tested, based on the response surface, a new experiment was performed using an increased T range from 5 to 90 min. Then, exposure time contributed significantly to the %TSS detachment, with the best result at 90 min. The use of ultrasound is therefore recommended, with volume that is easier to handle (250 mL) and time equal to 90 min. Additional tests are recommended for method standardization.
ABSTRACT
This study was designed to evaluate the performance of a cylindrical immobilized fixed Bed. Anaerobic digester in treating diluted municipal waste water. A series of three independent batch experiments was performed for a total operation time of 28 days. The system of anaerobic digestion showed stability conditions, with no noticeable scum or foaming problems. The anaerobic treatment of diluted municipal waste water is done using immobilized fixed bed anaerobic batch reactor. The source of waste generation is a mixed sludge collected from dock yard. The present study, thus initiated a need based experimental work on anaerobic digester incorporated with immobilized poly urethane foam system. The kinetic parameters are also estimated using experimental data. Empirical relations were developed for the characteristics like BOD, COD, SCOD, TDS and TSS using modeling equations.