Related Experiment Video
Updated: Jun 5, 2026

A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s
Published on: September 25, 2017
[Achieving the stability of nitrosation under low DO concentration]
1Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100022, China. herdu@yahoo.cn
Stable nitrite accumulation for enhanced nitrogen removal was achieved under low dissolved oxygen (DO). Optimizing chemical oxygen demand (COD) and hydraulic retention time (HRT) is key for efficient nitrosation.
Area of Science:
- Environmental microbiology
- Wastewater treatment technologies
- Nitrogen cycling in aquatic systems
Context:
- Secondary effluent from A/O phosphorus removal processes presents challenges for nitrogen removal.
- Achieving stable nitrite accumulation is crucial for subsequent denitrification.
- Low dissolved oxygen (DO) conditions are often associated with incomplete nitrification.
Purpose:
- To investigate the stable accumulation of nitrite under low DO conditions.
- To evaluate the effects of chemical oxygen demand (COD), hydraulic retention time (HRT), and sludge recycle ratio (R) on nitrosation efficiency.
- To determine optimal operating parameters for maximizing ammonia nitrogen removal and nitrite accumulation.
Summary:
- Stable nitrite accumulation was achieved using secondary effluent under low DO.
- Nitrosation rate was influenced by COD levels, increasing above 50 mg/L.
- Dynamic control of HRT and maintaining a sludge recycle ratio (R) of 0.5 were effective, while high R risked nitrification.
- Optimal conditions (HRT=6h, R=0.5, T=22-24°C) yielded 83% ammonia removal and near 100% nitrite accumulation.
Impact:
- Demonstrates a viable method for enhancing nitrogen removal in wastewater treatment.
- Provides insights into controlling nitrosation efficiency through key operational parameters.
- Offers a pathway for achieving high ammonia removal rates and significant nitrite accumulation, crucial for total nitrogen removal.
More Related Videos
08:23Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
07:30A Direct, Regioselective and Atom-Economical Synthesis of 3-Aroyl-N-hydroxy-5-nitroindoles by Cycloaddition of 4-Nitronitrosobenzene with Alkynones
Published on: January 21, 2020
Related Concept Videos
2° Amines to N-Nitrosamines: Reaction with NaNO2
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Rate-Determining Steps
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
Nitrosation of Enols
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
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...
Preparation of Amines: Reduction of Oximes and Nitro Compounds
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...