Ricerc@Sapienza

Among the emerging issues in the field of wastewater treatments, reducing energy
consumption and removal of new organic pollutants have become of primary concern.
With respect to the first goal, alternating oxic/anoxic conditions in the bioreactor
has demonstrated to be a feasible way to ensure the required efficiency of carbon
and nitrogen removal along with energy saving. The aim of the present study was
to investigate if these alternating oxic/anoxic conditions are also capable of boosting
organic micropollutants degradation, by stimulating the appropriate enzymes. Three
different aeration frequencies were tested in a laboratory scale activated sludge reactor
and the effects evaluated in terms of removal of carbon, nitrogen and a mixture of
OMPs (Sulfamethoxazole, Sulfadiazine, Lincomycin, Carbamazepine, Pyrazole, Naproxen,
Atrazine and Sucralose). It was also evaluated if these aeration strategies could change
the microbial community composition with respect to the control test conducted
under continuous air supply. Among the tested strategies, the longest and shortest
durations of anoxic conditions promoted the best removal for the majority of OMPs.
This enhancement was statistically well correlated to the activity increase of Lignin
Peroxidase and Cellulase enzymes whereas the microbial speciation did not change
statistically. The same durations were also capable of maintaining high carbon and
nitrogen removal rates within the same biological reactor.