Nitrate Treatment

Nitrate in water is usually due to agricultural waste or industrial wastewater containing nitric acid. The nitrate can be removed from the water using ion exchange, reverse osmosis, or biological treatment. When using ion exchange or reverse osmosis, the nitrate is concentrated into a brine. The concentrated brine can be treated either biologically or by drying. The most cost effective method of removing the nitrate is usually biological. In this process, the water is kept agitated and anoxic. The bacteria use the nitrate as a source of oxygen and reduce the nitrate to nitrogen. Roughly, 2.6 pounds of methanol are required for every pound of nitrate being treated. The methanol is the food source for the bacteria doing the nitrate reduction. If the incoming wastewater is high in BOD and nitrate, the biological treatment can use the BOD in the water as a food source instead of adding methanol.