title: The efficiency of ozonated water from a water treatment plant to inactivate Cryptosporidium oocysts during two seasonal temperatures.
abstract: We investigated the efficiency of residual ozone from an advanced water treatment plant with an applied dose of 2.5 mg l(-1) to inactivate viable Cryptosporidium oocysts during summer (i.e. 24 degrees C) and winter (i.e. 18.9 degrees C) in Queensland, Australia. Containers for sample collection were inoculated with 1,000 oocysts l(-1) and filled with ozonated water. Ozone residual concentrations were measured at 0, 5 and 10 min intervals. Viability was determined by excystation. Non-ozonated water from the plant, trip and laboratory controls were also analysed. The applied ozone dose of 2.5 mg l(-1) produced an immediate residual concentration of 1.25 mg 1(-1) at 24 degrees C and 1.34 mg 1(-1) at 18.9 degrees C in unseeded samples. The initial ozone residual in seeded containers was 1.22+/-0.03 mg 1(-1) at 24 degrees C and 1.37+/-0.04 mg 1(-1) at 18.9 degrees C. There was a gradual increase in inactivation of oocysts, with 49% of oocysts inactivated at 0 min to 92% after 10 min at 24 degrees C and 57% at 0 min to 92.8% at 10 min at 18.9 degrees C.
authors: Public Health Microbiology, Queensland Health Scientific Services, Archerfield, Queensland, Australia. tracey_wohlsen@health.qld.gov.au
authors: T
authors: T
authors: Wohlsen
authors: S
authors: S
authors: Stewart
authors: P
authors: P
authors: Aldridge
authors: J
authors: J
authors: Bates
authors: B
authors: B
authors: Gray
authors: M
authors: M
authors: Katouli
mesh_terms: D000818:Animals; D016785:Cryptosporidium parvum / Q000187:drug effects* / Q000502:physiology; D033661:Oocysts / Q000187:drug effects* / Q000502:physiology; D010083:Oxidants, Photochemical / Q000494:pharmacology*; D010126:Ozone / Q000494:pharmacology*; D012621:Seasons; D013696:Temperature; D018508:Water Purification / Q000379:methods
chemical_list: D010083:Oxidants, Photochemical; D010126:Ozone