Uso de micro-organismos eficientes (EM’s) na formação de biofilmes em espuma de poliuretano no tratamento de esgoto sanitário

Abstract

In this study we sought to verify what influence the efficient integration of Micro-organisms (EM 's) can play in biofilm formation in a system of sewage treatment . To achieve this goal it set up a biological treatment system consists of two reactors in Batch Sequential aerated (RBS ) identical , with insertion of EM’s ( RBS1 ) and without inclusion of EM’s ( RBS2 ), with the support means polyurethane foam for immobilization of biomass, both fed with sewage . These reactors operated with a hydraulic retention time (TDH) of 8 hours , and in each batch , RBS1 were inserted in 6.5 L of EM’s. Initial qualitative and quantitative characterization of EM's inserted into RBS1 was performed, as well as characterization of EM 's present in sewage in each collection held at SAMAE. The characterization of the EM's was performed by determining the colony forming unit / mL (UFC/mL) of three groups of EM's: fermenting lactic acid bacteria, yeasts and actinomycetes addition to heterotrophic bacteria. pH analyzes were performed in DQOT and sewage collected and output of both reactors . Total Solids Adhered analysis (STA) and Total Volatile Solids Adhered (STVA) was also performed in support medium. Regarding microbiological analyzes to quantify the UFC/mL of EM’s and heterotrophic bacteria attached to the polyurethane reactors foam were performed, and microscopic characterization of the diversity of attached and present micro-organisms in the effluent by fresh examination and morphotypes analysis the Gram stain . Macroscopic characterization of colonies of EM’s and cultivated heterotrophic bacteria was performed . The results showed that the final concentration of EM’'s in RBS1 was almost identical to the RBS2, indicating no difference in UFC/mL of EM’s and heterotrophic bacteria in both reactors. From the first hours of operation of the reactors there was an increase in biomass immobilized in all organisms , where 16 hours of operation all the group of EM's already had reached its highest concentration , and the fermenters of lactose increased from 104 to 107 UFC/mL , yeast 106 for 109 UFC/mL and actinomycetes 107 for 109 UFC/m . As for heterotrophic bacteria only after 224 hours of operation is that the peak was obtained in UFC/mL , starting 108 for 1010 . The analysis for STA and STVA indicated an increase of matter adhered in the middle of bracket 2 reactors. As for microfauna was no difference between the organisms observed in RBS1 and RBS2 observed, and these indicated that the system was run efficiently. The Gram stain showed predominantly streptococci and Gram negative streptobacilos both. And the macroscopic characterization indicated a wide variety of organisms examined for both groups. In general, it concludes that the EM 's concentration inserted into the RBS1 was not sufficient to provide the difference in biofilm formation in the reactor.