Abstract
Domestic wastewaters present high nitrogen levels due to the urea and ammonia, which are excreted into urine. Municipal wastewater treatment plants (WWTP) normally face some challenges in keeping their treated wastewater at a low total nitrogen concentration, since the majority of their wastewater is domestic. Low nitrogen levels in the treated wastewater are important to avoid increasing eutrophication of the receptor body, which receives the treated wastewater. This work presents an integrative review considering studies related to denitrification in domestic WWTPs published from January 1st, 2018, to April 30th, 2023. This review aims to identify the most effective methods for nitrogen removal in municipal WWTPs. The studies were classified based on the used technique: biological, chemical, electrochemical and statistical process control (SPC). They were evaluated according to their total nitrogen removal efficiency. Only reports with efficiency higher than 75% were included in this review. In total, 7 studies were analyzed, and their data correlated. It was possible to conclude that the most common approach to remove nitrogen in WWTPs was the chemical addition, seeing that it is hard to treat domestic wastewater due to its low carbon/nitrogen (C/N) ratio. So, an efficient technique is using a chemical substance to increase the carbon source. The four most efficient solutions to remove total nitrogen in WWTPs according to the present review are: increase the source of electron donor for the 2 denitrification process by adding acetate, methanol, or ferrous ion Fe(II) and H by microelectrolysis and inoculation of temperature-tolerant heterotrophic nitrifying-aerobic denitrifying bacterium Klebsiella sp. (KSND) seed culture.
Keywords
domestic wastewater; integrative review; nitrogen removal; sewage; treatment technology; wastewater treatment plant
Date of this Version
2-2026
Recommended Citation
Ferrarezzi, Cristiane G. and Duarte, Juliana Canto, "Efficiency evaluation of different methods for nitrogen removal in municipal wastewater treatment plants: An integrative review" (2026). The School of Sustainability Engineering and Environmental Engineering (SEE) Graduate Student Publications. Paper 1.
https://docs.lib.purdue.edu/eeegradpubs/1
Comments
Presented at the 5th Annual Grad WiE NetworkSymposium: Sharing Your Voice, Shaping Your Future. This symposium was held at Purdue University in West Lafayette on February 10, 2026.