The problem of wastewater treatment from noxious compounds, especially nitrogen, using chemical methods as the process control, is particularly relevant today. Nitrogen compounds come into the treatment plants mainly in the form of ammonia, nitrates, nitrites, and nitrogen bonded in organic compounds. The concentration of total nitrogen in domestic wastewater may vary depending on the origin of wastewater.
Changes in the composition begins during the wastewater transportation to municipal treatment facilities. In particular, the organic compound urea contained in domestic wastewater decomposes to ammonium form because of interaction with bacteria (ammonification process). Accordingly, the longer sewer network is, the deeper this process works.
There are no chemical methods of determining the total inorganic nitrogen. The value of this parameter is calculated mathematically as the sum of nitrogen compounds in the form of ammonium, nitrate and nitrite ions.