Dear Mehrnaz,

To effectively oxidise soluble manganese so that it can be subsequently removed by filtration, potassium permanganate requires a minimum of 5 to 20 minutes contact time at a pH value of 7.5 or greater. Potassium permanganate can be an effective oxidizing agent but is difficult to determine the correct dosing rate. Chemically, it should be dosed into the raw water supply in the ratio of 1.0 mg/L of potassium permanganate to 0.5 mg/L of soluble manganese.

It is an effective chemical for resolving dirty water complaints but over-dosing can cause a pink colour in the treated water so caution and visual monitoring is required. Also if supernatant liquor is recycled back to the inlet, maintain the pH in sludge tanks >7.0 to prevent manganese re-dissolving.

Dear Mehrnaz,

KMnO4 was used at the drinking water treatment plant in Burgos (Spain) to oxidise soluble iron and manganese (Fe2+ and Mn2+) a few years ago. They currently use O3 (pre-ozonation stage) instead. The concentrations of Fe2+ and Mn2+ in the reservoir ranged from 50 to 200 ppb and from 50 to 300 ppb, respectively. The permanganate dose used in the plant ranged from 0.50 to 0.90 ppm.

Kind regards from Spain.

Dr. Francisco J. Rodríguez

Thank you all for you comments and replies.

The application that I am talking is  pre-oxidation followed by coagulation to reduce the DOC and consequently THMs not manganese or iron removal.

can we apply the mentioned dose of KMnO4 for DOC removal purpose as well?

Thanks

The dose depends on tha value of COD..

the DOC is about 6-7 mg/L.

Dear Mehrnaz,

Potassium permanganate is not normally used in water treatment for the reduction of DBP potential. Although more expensive, Ozone is the preferred chemical.

At the normal dose rates used for iron and manganese reduction, potassium permanganate does not have a major impact on reducing DBP formation. At higher dose rates (> 2 mg/L) reductions of 30% to 40% have been achieved. This is about the same reduction as that achieved using ‘enhanced coagulation’ ie a slight excess of alum and a pH value around 5.8.

Thanks Michael

The problem with ozone in troposfere is that is  cancerogenic.

Tropospheric ozone and water ozonation are completely unrelated.

Ozone applied in water treatment is quickly consumed by reaction with reducing matter or breakdown to short lived radicals and oxygen in the absence of reducing matter so there is no exposure to water consumers.

Dose depends on the source of your drinking water and what is in it that has a demand and what you wish to treat: groundwater, surface water, snowmelt, sea water. Some links below including coagulation:

http://water.epa.gov/lawsregs/rulesregs/sdwa/mdbp/upload/2001_01_12_mdbp_alter_chapt_5.pdf

http://www.elaguapotable.com/Mejora%20coagulacion%20con%20permanganato.pdf

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCQQFjABahUKEwiJgeT27erIAhUBlx4KHZYFAmY&url=http%3A%2F%2Fwww.hach.com%2Fasset-get.download.jsa%3Fid%3D42654477504&usg=AFQjCNF0U3w-aYhxsILyzYQ8nPBxLvwUUQ

https://www.wpi.edu/Pubs/E-project/Available/E-project-030811-212708/unrestricted/Water_Quality_Assessment_and_Manganese_Treatment_for_the_Russell_F_Tenant_Water_Treatment_Facility.pdf

http://www.mrwa.com/WaterWorksMnl/Chapter%2014%20Iron%20and%20Manganese.pdf

http://www.academicjournals.org/journal/JECE/article-full-text-pdf/594B3841268

http://epa.ohio.gov/portals/28/documents/HAB/AlgalToxinTreatmentWhitePaper.pdf

http://sjostad.ivl.se/download/18.7df4c4e812d2da6a416800015338/1350483757437/LWR_EX_11_01.pdf

https://clu-in.org/download/contaminantfocus/arsenic/ArsenicTreatmentMTACFinalReport.pdf

The common problem is that ozone bubbles go the air.

Potassium permanganate is an oxidant, but a poor disinfectant. It’s often used in well water to control odor and taste, remove manganese, iron and color from the water, and to control biological growth that is considered a “nuisance,” such as the Asiatic clam, according to the Environmental Protection Agency. The substance is most often used as a pre-treatment before water is filtered, and is better at removing sulfide odors from water, dose of potassium permanganats depend on the characteristics of raw water, and the perpose that used for