What substances are used to remove impurities from drinking water

i know calcium hydroxide is one.. can you tell me other substances used?? and why and their disadvantages... i looked for that on google but couldnt find any

Chloramines and other chlorine like chemicals are the most common way to purify drinking water. Pure chlorine is also a commonly used chemical, but can be toxic if handled in the wrong ways or is present in too high of levels. Both chlorine and chloramines work to kill bacteria and other harmful substances

also Chlorine dioxide is another break off from chlorine that can be used to treat and purify drinking water. However, it is not used as often anymore because of the volatility of the gas that it produces (which is easily combustible).

If your talking about water purification as appose to drinking water purification then Algicide, Chlorine, Chlorine Dioxide, Clarifiers, Filter Cleansers, Dry or Muriatic Acid and Soda Ash or Sodium bicarbonate are all commonly used.

Hydrogen peroxide is another chemical that is often added to drinking water to help purify it. Hydrogen peroxide is usually combined with an activator called formic acid and works well on harmful protozoans and pathogens in the water supply. However, it takes longer to purify the water than chlorine, and can become a phytotoxin (or a plant poison capable of killing humans in a high enough dosage) if not used properly. It also changes the pH levels of the water, which requires additional chemicals to return the pH back to normal.

The purification methods vary depending on the area and what minerals and chemicals are most prominent in the water source

i think charcoal(c) is also the one u r searching for,pal
it is used as fuel, for purifying drinking water and decolorizing sugar