The feasibility of using peracetic acid (PAA) for wastewater disinfection, both for discharge into surface waters and agricultural reuse, was tested with reference to F. coli and E. coli as process efficiency indicators. PAA decay kinetics was evaluated in tap water and wastewater, in order to correlate PAA consumption to the physicochemical characteristics of the influent treated wastewater. In both cases, PAA decays according to a first order kinetics, with respect to time, and no apparent correlation was found between PAA consumption and wastewater initial characteristics. The sensitivity to PAA of the 2 microbial indicators was evaluated comparing log-survival ratios: F. coli was found to be less resistant than E. coli, which therefore appears not to be adequate to describe process efficiency. PAA disinfection efficiency was correlated with operating parameters (active concentration and contact time), testing different kinetic models (Chick-Watson, Selleck, Hom), which are commonly used for disinfection treatment design; a relationship specifically built for PAA (S-model) was also tested. Hom’s model was found to best fit experimental data in whole, while S-model, on the contrary, allows to better explain initial resistance of E. coli, especially at low PAA active concentrations (< 2 mg/L) and short contact times (< 12 min).
Bench scale PAA disinfection tests: evaluation of operating parameters
ANTONELLI, MANUELA;ROSSI, SABRINA;NURIZZO, COSTANTINO
2004-01-01
Abstract
The feasibility of using peracetic acid (PAA) for wastewater disinfection, both for discharge into surface waters and agricultural reuse, was tested with reference to F. coli and E. coli as process efficiency indicators. PAA decay kinetics was evaluated in tap water and wastewater, in order to correlate PAA consumption to the physicochemical characteristics of the influent treated wastewater. In both cases, PAA decays according to a first order kinetics, with respect to time, and no apparent correlation was found between PAA consumption and wastewater initial characteristics. The sensitivity to PAA of the 2 microbial indicators was evaluated comparing log-survival ratios: F. coli was found to be less resistant than E. coli, which therefore appears not to be adequate to describe process efficiency. PAA disinfection efficiency was correlated with operating parameters (active concentration and contact time), testing different kinetic models (Chick-Watson, Selleck, Hom), which are commonly used for disinfection treatment design; a relationship specifically built for PAA (S-model) was also tested. Hom’s model was found to best fit experimental data in whole, while S-model, on the contrary, allows to better explain initial resistance of E. coli, especially at low PAA active concentrations (< 2 mg/L) and short contact times (< 12 min).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
