Abstract

Pollution of water resources, such as nitrogen compounds, nitrate, and ammonium is increasingly expanding. A wide range of physico-chemical and biological methods are conducted for decreasing nitrate compounds and the amount of wastewaters. Due to low selectivity of nitrate, high costs, and the need for pre and post purification processes, the physico-chemical method is not effective for this purpose. However, biological methods are highly efficient in the removal of nitrogen compounds, and due to their advantages, they are widely used in wastewater purification. These methods include simultaneous nitrification and denitrification (SND), Anammox, and partial nitrification which are reviewed in the following chapter.