Disinfection tests were carried out at pilot scale to compare the disinfection efficiency of ozone, sodium hypochlorite (NaOCl), peracetic acid (PAA), and UV irradiation. Total coliforms, fecal coliforms, and Escherichia coli were monitored as reference microorganisms. Total heterotrophic bacteria (THB) were also enumerated by cytometry. At similar doses, NaOCl was more effective than PAA, and its action was less affected by contact time. The results obtained by ozonation were comparable for total coliforms, fecal coliforms, and E. coli. On the contrary, some differences among the three indicators were observed for NaOCl, PAA, and UV. Differences increased with increasing values of the disinfectant concentration times contact time (Ct) and were probably the result of different initial counts, as total coliforms include fecal coliforms, which include E. coli. The UV irradiation lead to complete E. coli removals, even at low doses (10 to 20 mJ/cm2). Total heterotrophic bacteria appeared to be too wide a group to be a good disinfection indicator; no correlation was found among THB inactivation, dose, and contact time.

Wastewater Disinfection Alternatives: Chlorine, Ozone, Peracetic Acid and UV Light

ANTONELLI, MANUELA;NURIZZO, COSTANTINO
2007-01-01

Abstract

Disinfection tests were carried out at pilot scale to compare the disinfection efficiency of ozone, sodium hypochlorite (NaOCl), peracetic acid (PAA), and UV irradiation. Total coliforms, fecal coliforms, and Escherichia coli were monitored as reference microorganisms. Total heterotrophic bacteria (THB) were also enumerated by cytometry. At similar doses, NaOCl was more effective than PAA, and its action was less affected by contact time. The results obtained by ozonation were comparable for total coliforms, fecal coliforms, and E. coli. On the contrary, some differences among the three indicators were observed for NaOCl, PAA, and UV. Differences increased with increasing values of the disinfectant concentration times contact time (Ct) and were probably the result of different initial counts, as total coliforms include fecal coliforms, which include E. coli. The UV irradiation lead to complete E. coli removals, even at low doses (10 to 20 mJ/cm2). Total heterotrophic bacteria appeared to be too wide a group to be a good disinfection indicator; no correlation was found among THB inactivation, dose, and contact time.
2007
Wastewater; disinfection; chlorination; ozonation; Peracetic acid; UV irradiation; fecal coliforms; Escherichia coli
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/546199
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 78
  • ???jsp.display-item.citation.isi??? 65
social impact