Potash and Sand filter for water treatment

Source:http://www.livestrong.com/article/71333-use-potassium-permanganate-water-treatment/

The potassium permanganate dose needed for oxidation is 0.94mg per milligram of iron and 1.92mg per milligram of manganese. Rates of oxidation will depend on the pH. Iron oxidation can occur within 10 minutes if the pH is 7.2 or more, but can require an hour if the pH is 6.9, according to the University of Iowa. Manganese oxidation will be slower. It requires less than one hour only at a pH of 9.5 or above. You may need a detention tank to give adequate time for iron and manganese to oxidize. If you are treating taste and odor, use doses of potassium permanganate ranging from 0.25 to 20mg per liter according to the manufacturer’s instructions.

Source::http://www.cwejournal.org/vol7no1/reverse-osmosis-pretreatment-removal-of-iron-in-groundwater-desalination-plant-in-shupramant-giza-a-case-study/

iron was removed in groundwater before passing through reverse osmosis membranes as pretreatment technique to avoid membrane fouling. Different pretreatment techniques are done to remove iron and save the membrane.

Many processes affecting the iron removal from the groundwater are applied in this case study. From the performance comparison between conventional and specific pre-treatment methods, we concluded that, every applied method has advantages and disadvantages in application. The most suitable pretreatment  technique for iron removal (concentration less than 5 mg/l) is a granular activated carbon (GAC) filter which has higher adsorption capacity and leads to low
operating cost.

The depth of the GAC media is estimated based on the average contact time in this media, which is recommended to be 10 to 12 min. For example, if a filter is designed for a surface loading rate of 4 m3/m2 h, the depth of the GAC media should be at least 0.66 m (4 m3/m2 h ×10 min/60 min per h=0.66 m to 4 m3/m2 h ×12 min/60 min per h=0.8 m, i.e., 0.66 0.8 m)15. For the following reasons28, we used the granular activated carbon in the adsorption of ferrous.

Potassium Permanganate and Depth Filtration

Conventional treatment for iron removal from groundwater consists of oxidation and depth filtration. Oxygen or stronger oxidants, such as potassium permanganate (KMnO4), are generally used for Fe 2+oxidation. The solid products of oxidation (FeOOH.H2O) are then filtered through a granular bed, commonly green sand19. The potassium permanganate dose applied must be carefully controlled to minimize any excess passing into supply which could give a pink color to the water. Potassium permanganate oxidation tends to form a colloidal precipitates which may not be well retained by the filters.

Detailed description of water treatment

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sand-anthracite filter for iron removal

A sand-anthracite filter or dual media filter/multi-media filter is primarily used for the removal of turbidity and suspended solids as low as 10-20 microns. Inside a sand-anthracite filter is a layered bed of filter media. The bed is graded from bottom to top as follows:

1st layer	=	gravel support bed
2nd layer	=	2mm filter sand
3rd layer	=	fine filter sand
4th layer	=	anthracite

 Anthracite has a high affinity for iron, especially when it is coated with potassium permanganate, and is therefore often employed for iron and manganese removal.

Well water iron treatment, Drinking Water Treatment - Potassium Permanganate

 Its an age old method to use potassium permanganate(1% solution) in the well water and then pass it through slow sand filter. It removes Iron from well water.

 potassium permanganate(1% solution)  is effective against: dissolved iron, manganese and hydrogen sulfide.

. Potassium permanganate is a point-of-entry treatment method that oxidizes dissolved iron, manganese, and hydrogen sulfide into solid particles that are filtered out of the water. It can also be used to control iron bacteria growth in wells.

Potassium permanganate is available as a dry, purplish solid. A device injects a solution of potassium permanganate into the water between the water pump and holding tank.

Potassium permanganate oxidizes iron, manganese, and hydrogen sulfide into particles. The particles are then filtered with a multimedia filter which can be either manganese-coated aluminum silicate above manganese-treated green sand or an 8-inch layer of anthracite above manganese-treated greensand. If an insufficient amount of iron, manganese, or hydrogen sulfide is oxidized prior to filtration, the manganese coating on the filter media acts as a backup oxidant to treat any remaining contaminant. If too much potassium permanganate is fed into the water prior to filtration, the excess potassium permanganate serves as a regenerant for the filter media. The water should be colorless when it leaves the filter.

When treating water to remove iron bacteria, a solution of potassium permanganate is fed into the well. A concentration of 3.8 to 7.6 grams per gallon has been found to be very effective. After the solution is added in the well, continuous agitation will help loosen and disintegrate sediment and organic material produced by the bacteria, thus enhancing treatment effectiveness. Agitation can be accomplished by turning the well on and off, which brings water up through the well casing and then lets it fall back into the well.

Potassium permanganate is poisonous and irritates skin, so handle it carefully and ensure that there is no excess potassium permanganate in the treated water. The chemical gives water a slight pink tint. Water should be colorless after treatment.

Adapted from: Wagenet,L., K. Mancl, and M. Sailus. (1995). Home Water Treatment. Northeast Regional Agricultural Engineering Service, Cooperative Extension. NRAES-48. Ithaca, NY.

Source of the article:: http://articles.extension.org/pages/31569/drinking-water-treatment-potassium-permanganate