CHARACTERISTIC OF GRANULATED ACTIVATED SLUDGE FED WITH GLYCERIN FRACTION FROM BIODIESEL PRODUCTION

In the presented research glycerin fraction from biodiesel industry was used for granulated aerobic activated sludge production ill a typical sequencing batch reactor (h/d equal 2.1). After 7 weeks of operation, granulated activated sludge with SVI at the level of 40-50 cm(3).g(-1) was obtained. At organic compounds load of 1.43 +/- 0.1 mg COD.mg VSS-1.d(-1), the efficiency of carbon removal was 94.14 +/- 2.7% and most of the introduced COD was removed during the first 2-3 hours of aeration. The sieve analysis revealed that 60% (w/w) of biomass consisted of particles with a diameter ill the range of 4-8 mm. A free settling test procedure proved that granules with a diameter between 2-4 mm were numerically most abundant in biomass (32.3%) and that the settling volume, mass and Reynolds number values significantly (p < 0.05) increased parallel with increasing granule diameter. Adverse tendency was observed for the mean effective, buoyant density of a granule in a liquid.