Sodium Permanganate

[disney7]

So, I was just talking to the head engineer for my household water treatment plant. They currently use bleach (chlorine) to treat the water. Apparently algae is the main concern. However, because of new guidelines (something about the compounds created as a result of the chlorine killing stuff) they may have to switch to or complement with sodium permanganate.

So, what would I expect this to do to my brewing water? I would guess it would add some sodium and magnesium. Any idea if typical treatment would just result in negligible amounts or more?

Currently my water is very soft. I have been running a test in the summer and winter for the last couple of years and it has never changed much. Here are the most current numbers from Ward Labs:

pH 7.7
Total Dissolved Solids (TDS) Est, ppm 51
Electrical Conductivity, mmho/cm 0.09
Cations / Anions, me/L 0.8 / 0.5
ppm
Sodium, Na 8
Potassium, K < 1
Calcium, Ca 6
Magnesium, Mg 1
Total Hardness, CaCO3 19
Nitrate, NO3-N < 0.1 (SAFE)
Sulfate, SO4-S 1
Chloride, Cl 7
Carbonate, CO3 < 1
Bicarbonate, HCO3 16
Total Alkalinity, CaCO3 13
Total Phosphorus, P 0.28
Total Iron, Fe < 0.01

 

[Hoser_brewing]

Permanganate adds manganese, not magnesium.

I'm not a water engineer, but it sounds like they'd be adding it as a pretreatment step, rather than in the municipal distribution lines. I know there's usually some MnO2 or other Mn salts in the water, as tap water recirculation lines in my lab have a delicious brown coating of the stuff on them, but I'd guess they wouldn't allow massive levels of it to be present in drinking water.

 

[Hoser_brewing]

And to follow up, in MA they have a spec of 50 ug/L (ppb) on Mn, but that's an aesthetic limit set by the department of environmental protection, not a health limit.

See p9 of http://www.mwra.state.ma.us/monthly/wqupdate/pdf/cy2013/102013.pdf for more details.

 

[ajdelange]

When permanganate oxidizes something the result is the insoluble oxide of manganese. This should be taken out by the system's filtration. You should expect a small increase in sodium, however.