No abstract

This work reports on simultaneous nitrification, denitrification and phosphorus removal treating real domestic wastewater with low carbon/nitrogen (C/N) ratio by aerobic granular sludge (AGS). Operations at high sludge retention time (SRT = 61 ± 24 days) resulted in low biomass yield per chemical oxygen demand removed (COD rem ) (0.21 ± 0.01 gCOD x /gCOD rem ), lower COD demand for denitrification as well as high effluent quality in terms of total suspended solids (TSS) (22 ± 7 mgTSS/L). The average ratio between the biodegradable soluble COD stored anaerobically as polyhydroxyalkanoates (PHAs) and the N removed was 3.1 ± 0.6 gCOD sto /gN rem , suggesting that nitrification/denitrification occurred partly via the nitrite pathway. Results revealed that stable AGS process with high C/N/P removal efficiency of 84/71/96% can be obtained besides a low organic loading rate (0.43 ± 0.11 g COD/L/d) and influent C/N ratio (3.8 ± 1.6 g/g), resulting in a high effluent quality characterized by 25 ± 6 mg sCOD/L, 0.09 ± 0.

No abstract

The suitability of the anammox process for the treatment of swine digester liquor was assessed through the evaluation of the short- and long-term inhibitory effect of three veterinary antibiotics commonly administered to Italian swine livestock. The toxicity of doxycycline, tiamulin and enrofloxacin was evaluated through batch tests designed to estimate specific anammox activity. Moreover, the short-term toxicity of combined concentrations of doxycycline and enrofloxacin was evaluated so as to verify whether a synergistic effect could be established. According to the inhibition recorded in the presence of the maximum antibiotics concentrations predicted for digester liquor, target compounds do not seem to represent a real hazard for anammox bacteria because at those concentration levels, the activity was just slightly reduced. Moreover, in granular systems, inhibition could be easily counterbalanced by increasing the biomass concentration in the reactor, thus assuring the design treatment capacity for antibiotic-rich wastewaters.

No abstract