Ammoniacal nitrogen is an acidic chemical used primarily for waste treatment, water purification and liquid fertilizers. It is a combination of the chemical element nitrogen and ammonia, with the latter being a chemical compound of nitrogen and hydrogen.
Ammoniacal nitrogen is often used to determine the health of rivers, lakes and human-made reservoirs. Ammonia can be harmful to water systems and humans who come into contact with them. For this reason, the level of ammoniacal nitrogen released into the water is carefully measured and, if necessary, lowered. Ammoniacal nitrogen is found in many household water-soluble fertilizers, which lower the pH of soil and provide the necessary nutrients to help plants grow.