Once upon a time, if you bought a child a chemistry set, you could find a tube of potassium permanganate in it. This potent oxidizing agent reacts with a range of organic compounds.
For example, it can oxidize iron and hydrogen sulfide (the rotten egg smell) in water treatment. It can also be used to control taste and odor in drinking water and to improve sludge dewatering.
Disinfection
Among the most popular potassium permanganate uses in water treatment, it is a strong oxidizing chemical, so it’s used in disinfection and odor control in water treatment. It effectively removes organic material and bacteria and reduces dissolved iron, manganese, and other heavy metals. It also oxidizes hydrogen sulfide and other odor-causing compounds in water.
It’s often combined with other chemicals to treat specific water contaminants. For example, it is commonly used with copper sulfate to reduce iron and manganese in drinking water. It’s also used with ozone to reduce sulfide odors.
Because potassium permanganate irritates skin and leaves dark stains, it’s essential to protect the eyes and hands when handling it. It should never be ingested or inhaled. It is poisonous at high concentrations and can cause severe burns, so it should be kept out of reach of children. It should be stored in the original containers and protected from physical damage. It’s a good idea to have your water tested before using it.
Odor Control
Potassium permanganate can oxidize hydrogen sulfide, other organic contaminants, iron, and manganese. According to the Environmental Protection Agency, it’s also better than chlorine at removing odor from water. In addition, it kills pesky freshwater organisms like Asiatic clams and zebra mussels in reservoirs and water treatment plants.
It’s used to treat well water that contains iron and hydrogen sulfide, which produce the “rotten egg” odor. It’s also good at preventing the buildup of iron and manganese in filters, and it improves sludge dewatering.
Unlike most strong oxidants, potassium permanganate doesn’t produce objectionable trihalomethanes. It can also control organic contamination and phenolic tastes, but doesn’t work against algal tastes and odors like chlorine dioxide or ozone.
Potassium permanganate is a caustic irritant when dry, so it’s recommended to use gloves and protective eyewear when handling it. It can stain skin brown, so it’s important to rinse away any contact immediately. A diluted solution of KMnO4 can be used to treat dermatitis and fungal infections. It also kills the parasite Ichthyophthirius multifiliis, which infects and usually kills freshwater fish.
Water Treatment
One of the potassium permanganate uses in water treatment is to eliminate odors and reduce iron and manganese levels. It oxidizes dissolved iron and manganese, turning them into solid particles that can be filtered out of the water.
The oxidation process also kills bacteria, viruses, and other organisms that might be present in the water. It can also oxidize organic pollutants, breaking them into smaller molecules or tiny particles that can be removed from the water.
The chemical is highly poisonous and irritates the skin, so keeping the concentrated form of potassium permanganate away from children is vital. It is a dark purple or black substance with the chemical formula KMnO4. It should be stored in a cool, dry place, protected from physical damage.
The compound’s staining properties are used in the film and TV props industry, where it is used to discolor fabrics. It also produces dramatic, deep brown stains on metals like stainless steel and glass.
Soil Treatment
In the garden, potassium permanganate oxidizes organic matter in the soil to reduce the amount of nitrogenous waste and helps to control fungal growth. It is readily available in pharmacies and specialized horticultural outlets.
In rural areas, potassium permanganate removes iron and hydrogen sulfide (rotten egg smell) from healthy water. A solution is applied to the ground surface, and a pipe network is inserted downstream of the contamination. The polluted groundwater is pumped into the permanganate system, which oxidizes the contaminants. The oxidized chemicals are reduced to less toxic forms that can be more easily disposed of in public sewers or into a nearby river or pond.
When dissolved in water, potassium permanganate produces deep brown manganese dioxide that stains skin and other materials. It can also oxidize phenolic and amine compounds to produce very toxic substances. Its oxidative properties make it an adequate substitute for chlorinating reagents in drinking water treatment, avoiding the formation of harmful byproducts.
