22.214.171.124 Bacteria Inactivation
High dosage rates were required to accomplish complete inactivation of bacteria in three studies.
Early research showed that a dose of 2.5 mg/L was required for complete inactivation of coliform Bacteria (Le Strat, 1944). In this study, water from the Marne River was dosed with potassium permanganate at concentrations of 0 to 2.5 mg/L. Following mixing, the samples were placed in a darkened room for 2 hours at a constant temperature of 19.8oC.
Banerjea (1950) investigated the disinfectant ability of potassium permanganate on several waterborne pathogenic microorganisms. The investigation studied Vibrio cholerae
, Salm. typhi
, and Bact. flexner
. The results indicated that doses of 20 mg/L and contact times of 24 hours were
necessary to deactivate these pathogens; however, even under these conditions the complete absence of Salm. typhi
or Bact. flexner
was not assured, even at a potassium permanganate concentration that turned the water an objectionable pink color.
Results from a study conducted in 1976 at the Las Vegas Valley Water District/Southern Nevada System of Lake Mead water showed that complete removal of coliform bacteria were accomplished at doses of 1, 2, 3, 4, 5, and 6 mg/L (Hazen and Sawyer, 1992). Contact times of 30 minutes were
provided with doses of 1 and 2 mg/L, and 10 minutes contact times were provided for higher dosages in this study.
126.96.36.199 Virus Inactivation
Potassium permanganate has been proven effective against certain viruses. A dose of 50 mg/L of potassium permanganate and a contact time of 2 hours was required for inactivation of poliovirus (strain MVA) (Hazen and Sawyer, 1992). A “potassium” permanganate dose of 5.0 mg/L and a
contact time of 33 minutes was needed for 1-log inactivation of type 1 poliovirus (Yahya et al.,1990b). Tests showed a significantly higher inactivation rate at 23oC than at 7oC; however, there was no significant difference in activation rates at pH 6.0 and pH 8.0.
Potassium permanganate doses from 0.5 to 5 mg/L were capable of obtaining at least a 2 log inactivation of the surrogate virus, MS-2 bacteriophage with E. coli
as the host bacterium (Yahya et al., 1989). Results showed that at pH 6.0 and 8.0, a 2-log inactivation occurred after a contact time of at least 52 minutes and a residual of 0.5 mg/L. At a residual of 5.0 mg/L, approximately 7 and 13 minutes were required for 2-log inactivation at pHs of 8.0 and 6.0, respectively. These results contradict the previously cited studies that potassium permanganate becomes more effective as the pH decreases.
188.8.131.52 Protozoa Inactivation
No information pertaining to protozoa inactivation by potassium permanganate is available in the literature. However, based on the other disinfectants discussed in this report, protozoa are significantly more resistant than viruses; therefore, it is likely that the dosages and contact times required for protozoa inactivation would be impractical.
Chapter 05 page 06-
EPA Guidance Manual April 1999
Alternative Disinfectants and Oxidants