Will pink coloration cause interference with analysis of wastewater when testing for Phenol?

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An industrial permittee has a wastewater that has a slight pink coloration after the pretreatment process. The samples need to be analyzed for Phenol in accordance with 40 CFR 403 and 40 CFR 136. Will the pink coloration cause interference with the analysis?

Experts Response:
The pink color will probably be removed in the distillation, but one way of being sure would be to conduct the test without the addition of the 4-aminoantipyrene color reagent. This should give a result of close to zero if there is no interference. If there is interference, the phenolics result could be approximated by subtracting the value obtained without adding the reagent to the value obtained with adding the reagent.

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Potassium permanganate to oxidize phenol from landfill leachate as treatment process

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We would like to use potassium permanganate (KMnO4) to oxidize phenol from landfill leachate as a treatment process (i.e. reduce phenol below POTW required limits) prior to sending leachate to a local POTW. However, we are not sure what could potentially be formed when the KMnO4 oxidizes the phenol and how these subsequent formation products should then be removed. 

Expert Response: 

The reaction product of phenol and permanganate will be 1,4-benzoquinone. It is not regulated, and I suspect that it will be degraded in a biological treatment system. Since your treated leachate is going to a POTW, this should be sufficient to eliminate both the phenol and the by-product.

Ask the Expert Question: 

We also would need to know what potassium permanganate (KMnO4) would do to ammonia, cyanide, hydrogen sulfide and dissolved metals which are also present in the leachate at lesser concentrations than the phenol. 

Expert Response: 

Regarding the reaction of permanganate with the other constituents, I would expect ammonia to be oxidized to nitrate, cyanide to carbon dioxide and nitrate, and sulfide to sulfate. 

With the metals it would depend on the specific metals and their oxidation states.  For example, the leachate probably contains some dissolved ferrous iron because the landfill will be a reducing environment. The reaction with permanganate will convert this ferrous iron to ferric iron, and that would almost certainly result in a ferric oxide precipitate. These constituents are likely to react with permanganate more quickly than phenol, so you will have to add sufficient permanganate to oxidize these before you will get thorough oxidation of the phenol.