Evaluation of the chlorination effect on filamentous and floc-formers microorganisms in activated sludges

CARAVELLI A.; CONTRERAS E.; GIANNUZZI L.; ZARITZKY N.

Roma, Italia

Congreso; 3rd IWA International Specialised Conference on Microorganisms in Activated Sludge and Biofilm Processes; 2001

The effect of chlorine in pure cultures of Sphaerotilus natans and Acinetobacter anitratus and in activated sludges was evaluated using different techniques. S. natans was more susceptible to the toxicant action at low chlorine concentrations than A. anitratus; however, at higher doses the effect was the opposite. Activated sludge studies showed complete inhibition of the respiratory activity of the filamentous micro-organisms at all tested conditions; however, the inhibition of the sludge respiration was lower (40% - 60% of the untreated system). The obtained results showed that similar chlorination conditions led to a higher inhibition of filamentous micro-organisms in the floc than of the whole activated sludge. Therefore, filamentous micro-organisms location (outer zone of the flocs) determines its higher susceptibility to chlorine than the floc-forming ones and plays a critical role in the performance of bulking control.