"Phoraid" Disinfectant
Water Treatment Study – March 2003. Carried out by William Keane B.Sc.,
Manufacturing Chemist
for
Phoraid International, U.K.
Water Treatment Study – March 2003. Carried out by William Keane B.Sc.,
Manufacturing Chemist
for
Phoraid International, U.K.
Because iodine retains its activity over a wider range of pH values than chlorine, it has been advocated for
the sterilisation of drinking water, especially under emergency conditions, and for the treatment of
swimming pool water. Change & Moms (1953) recommended a concentration of 8 parts per million, chosen because
at such a level it is lethal to most water-borne pathoganie organisms, including amoebae and virus in
about 10 minutes at normal temperatures, or rather longer at lower temperatures. Later Change (1958) put the
level at 4 parts per million with a contact time 15-20 minutes. These concentrations appear to be high in
comparison with the findings of Chambers et a!. (1952), but it must be borne in mind that the treatment was
intended for waters of unknown and doubtful quality (Moms et a!. 1953. Chambers assessed the minimum concentrations
lethal in 1 minute against range of organisms of intertinal origin and found that whereas 4.5 parts per million in
cold water at pH 9.1, 0.6 part was adequate at pH 6.5 and in the ambient temperature range of 20—26deg.
the sterilisation of drinking water, especially under emergency conditions, and for the treatment of
swimming pool water. Change & Moms (1953) recommended a concentration of 8 parts per million, chosen because
at such a level it is lethal to most water-
level at 4 parts per million with a contact time 15-
intended for waters of unknown and doubtful quality (Moms et a!. 1953. Chambers assessed the minimum concentrations
lethal in 1 minute against range of organisms of intertinal origin and found that whereas 4.5 parts per million in
cold water at pH 9.1, 0.6 part was adequate at pH 6.5 and in the ambient temperature range of 20—26deg.
Alkaligenes faecalis is said to be the most difficult of bacteria to deal with in swimming pools, being about six
times more resistant than the coliforms, salmonellae and shingellae (Marshall, Wolford and Faber, 1961).
times more resistant than the coliforms, salmonellae and shingellae (Marshall, Wolford and Faber, 1961).
More recently in 1966 it was determined that using a more stable complexed iodophore
— (Phoraid 5000WT) – 5WT 5% Av 12 plus 5% citric acid it was highly effective at the following dilutions:
— (Phoraid 5000WT) – 5WT 5% Av 12 plus 5% citric acid it was highly effective at the following dilutions:
25 Parts per million effective in 4 minutes contact time (99.999%)
10 Parts per million effective in 60 minutes
5 Parts per million effective in 24 hours
Large volumes 0.5 ppm pH 5 to 6
"PHORAID" is effective against many or all water borne bacteria, fungi, algae and can be
used to treat water for chickens, animals, and human consumption.
It controls spore forming bacteria and the more resistant coliforms.
10 Parts per million effective in 60 minutes
5 Parts per million effective in 24 hours
Large volumes 0.5 ppm pH 5 to 6
"PHORAID" is effective against many or all water borne bacteria, fungi, algae and can be
used to treat water for chickens, animals, and human consumption.
It controls spore forming bacteria and the more resistant coliforms.
