Denitrification efficiency in wastewater treatment is dependent on several environmental conditions. The wastewater plant must maintain a consistent anoxic zone, abundance of denitrifying microorganisms, and organic carbon source. For optimum performance, denitrifying bacteria require a low dissolved oxygen region in the treatment process removed from aeration. Having an adequate proportion of these organisms is essential for removing bioavailable nitrogen, nitrate, from raw wastewater. Discharge to the anoxic zone can contain less carbon than is needed to achieve comprehensive denitrification.