Potassium Permanganate (Draft)

Potassium Permanganate (also written as KMnO₄) is typically used in water supply treatment plants to oxidize soluble iron and manganese to insoluble precipitates for removal by filtration, and for taste and odor and zebra mussel control. Under normal operations the finished water contains no residual potassium permanganate. Any residual of this chemical will turn the water pink (0.25mg/l) to dark pink (10 mg/l) to purple (1%) in color depending on the concentration; the darker the color the stronger the concentration. A malfunction at a water treatment plant can result in this chemical being present in the finished water. This is immediately noticeable due to the pink to purple color of the water. The presence of this chemical in the finished water is usually of a short term nature. However, certain precautions should be taken until the chemical is flushed out of the system and the water returns to normal.

The basic precaution to take is not to drink or consume the water that has a 'pink' color to it; bottled water can be used as a temporary supply. Dermal contact should also be avoided, especially if the water is highly colored. These same precautions would apply to animals and fish. Staining and fabric damage may occur to laundry; vegetation can also be damaged. Some specific information is as follows: a fatal oral dose in a 175 pound man is 0.5 gallons of a 5% solution on an empty stomach, concentrations of more than 200 mg/l may cause tissue damage, lower concentrations will dry out membranes in the eye, mouth and throat.

The chemical is removed by flushing out the distribution system. The water department will be flushing hydrants, customers should flush their own plumbing system. A brown discoloration may persist for a few days especially for those customers on a dead end water main.     May 6, 1996

Surface Water Treatment Rule

See Turbidity and Microbiological.