Related Experiment Video
Updated: Aug 15, 2026
08:05
Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Nitrification-denitrification via nitrite accumulation for nitrogen removal from wastewaters
1School of Biochemical Engineering, Universidad Católica de Valparaiso, General Cruz 34, 234-0950 Valparaiso, Chile. gruiz@usc.es
Bioresource Technology
|September 21, 2005
Summary
Optimizing biological nitrogen removal via nitrite accumulation in wastewater treatment offers significant savings. This study controlled dissolved oxygen for maximum nitrite, achieving 93.5% nitrogen removal.
Area of Science:
- Environmental Science
- Biotechnology
- Water Treatment Engineering
Background:
- Biological nitrification-denitrification is a key process for ammonia nitrogen removal from wastewater.
- Achieving nitrite accumulation during nitrification can lead to substantial savings in aeration, organic matter, and sludge production.
- Optimizing operational parameters is crucial for maximizing nitrite accumulation and adaptation in wastewater treatment.
Purpose of the Study:
- To investigate operational parameters for maximizing nitrite accumulation in the nitrification step.
- To assess nitrite adaptation in the denitrification step for stable and efficient nitrogen removal.
- To compare the performance of continuous stirred tank reactors (CSTR) and upflow sludge blanket (USB) reactors.
Main Methods:
- Studied operational parameters, focusing on dissolved oxygen (DO) concentration for nitrification.
- Investigated nitrite adaptation in the denitrification process.
- Compared CSTR and USB reactor performance in a series configuration.
Main Results:
- Nitrite accumulation during nitrification was maximized at approximately 65% with a DO concentration around 0.7 mg/L.
- Denitrification demonstrated stability when adapted to nitrite, provided low nitrite levels were maintained in the reactor.
- A combined CSTR (nitrification) and USB (denitrification) system achieved a stable 93.5% overall nitrogen removal.
Conclusions:
- Controlled dissolved oxygen is critical for maximizing nitrite accumulation in biological nitrification.
- Wastewater denitrification can be effectively adapted to nitrite, ensuring process stability.
- The nitrification-denitrification via nitrite process, utilizing optimized parameters and reactor configurations, is highly efficient for nitrogen removal.
Related Concept Videos
01:30Microbial Wastewater Treatment
Microbial communities in aquatic ecosystems play a key role in the natural breakdown of contaminants introduced through domestic and industrial effluents. Acting as biological catalysts, these microbes change and mineralize a wide range of organic and inorganic pollutants under different redox conditions.In oxygen-rich surface waters, aerobic heterotrophs lead organic matter breakdown, using oxygen as the terminal electron acceptor to efficiently oxidize substrates to carbon dioxide and water.
01:20Overview of Nitrogen Metabolism
Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of ammonia, ammonium ions, nitrate, nitrite, or nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
01:22Inorganic Nitrogen Assimilation
Nitrogen is an essential element in biological systems, forming a crucial component of proteins, nucleic acids, and other cellular constituents. Many bacteria and archaea acquire nitrogen in the form of nitrate (NO₃⁻) or ammonia (NH₃), which are then assimilated into biomolecules through specific enzymatic pathways.Assimilatory Nitrate ReductionWhen nitrate enters the cell, it undergoes a two-step reduction process known as assimilatory nitrate reduction. Initially, the enzyme nitrate reductase...
01:202° Amines to N-Nitrosamines: Reaction with NaNO2
Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.
01:30Biological Treatment of Effluent and Waste Water
Biological wastewater treatment relies on the metabolic activity of microorganisms to remove pollutants from sewage. In modern treatment systems, this process is organized into sequential stages that progressively reduce solid material, dissolved organic matter, and microbial contamination. Each stage plays a distinct role in improving water quality and preparing the effluent for safe discharge or reuse.Primary and Secondary TreatmentPrimary treatment is a physical process that removes large...
01:261° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...