What is used to regenerate manganese greensand filters?

Manganese greensand filters are utilized in water treatment to remove iron, manganese, and hydrogen sulfide from water sources. To maintain their effectiveness after a period of use, these filters require regeneration. Potassium permanganate is used for this regeneration process due to its strong oxidizing properties, which help to restore the filter media to its original state.

When potassium permanganate is introduced to the greensand, it oxidizes the iron and manganese that have accumulated on the filter, allowing for their removal. Through this process, the greensand becomes more effective in treating the water again. This regeneration process is essential for the longevity and efficiency of the filtration system. Other substances mentioned in the choices do not serve the same purpose in regenerating manganese greensand filters.