Transient behaviour and time aspects of intermittently and continuously fed bacterial cultures with regard to filamentous bulking of activated sludge
Faculty of Applied Engineering Sciences
Engineering sciences. Technology
Applied microbiology and biotechnology. - Berlin, 1984, currens
, p. 44-52
Pure culture transient experiments with Arthrobacter globiformis and Sphaerotilus natans revealed that the floc-forming species A. globiformis can adapt better to intermittent feeding (I-feeding) than the filamentous species S. natans. The floc-forming bacterium showed a larger overcapacity for substrate uptake, a larger accumulation of reserves (polysaccharides and poly-β-hydroxybutyric acid) and a more efficient mobilization of these polymers. As a consequence A. globiformis became dominant in an I-fed dual culture of S. natans and A. globiformis. The transient behaviour of filamentous continuously fed (C-fed) sludge was similar to the response of S. natans. Consequently, I-feeding of activated sludge could prevent the excessive growth of filamentous bacteria. I-fed sludge, showed a higher overcapacity, the accumulation of more reserves and a shorter lag phase in protein synthesis than C-fed activated sludge, during the transient response, after a pulse dose of substrate. However, to be effective in the control of bulking, the frequency of I-feeding should allow for a sufficiently long endogenous phase. In addition the available fraction of the COD is important in the optimization of I-feeding as a control strategy for filamentous bulking.