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Updated: Feb 15, 2026
08:18
Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions
Published on: June 12, 2016
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Correlation between nitrous oxide (N2O) emission and carbon to nitrogen (COD/N) ratio in denitrification process: a
Mehran Andalib1, Edris Taher1, Joseph Donohue1
1Environmental Operating Solution Inc. (EOSi), Bourne, MA, USA
Summary
In-situ probes for nitrogen monitoring can lose accuracy at low levels, potentially causing issues in denitrification control. Nitrous oxide (N₂O) sensors offer a promising alternative for automated biological nutrient removal.
Area of Science:
- Environmental Engineering
- Water Treatment Technologies
- Process Automation
Background:
- In-situ ion selective electrode and ultraviolet probes for nitrogen (NOx) monitoring face accuracy challenges at low concentrations (<1.0 mg N/L).
- Compromised NOx probe accuracy can lead to overfeeding external carbon sources in denitrification processes.
- Nitrous oxide (N₂O) sensors present a novel opportunity for automating biological treatment processes.
Purpose of the Study:
- To evaluate the reliability of in-situ NOx probes under varying operational conditions.
- To investigate the potential of in-situ N₂O sensors for automating denitrification.
- To explore the correlation between NOx and N₂O production and influencing operational parameters.
Main Methods:
- Investigated the accuracy and stability of in-situ NOx probes at four treatment plants.
- Deployed in-situ N₂O sensors in parallel with NOx probes at two treatment plants.
- Analyzed the effects of Chemical Oxygen Demand to Nitrogen (COD/N) ratios and other operational conditions on N₂O production.
Main Results:
- NOx probes exhibited compromised accuracy and trending stability at NOx levels below 1.0 mg N/L.
- N₂O production was correlated with influent nitrogen load and COD/N ratios under specific dissolved oxygen and pH conditions.
- N₂O sensors demonstrated applicability for monitoring denitrification processes.
Conclusions:
- In-situ NOx probes are unreliable for precise control of denitrification at low concentrations.
- In-situ N₂O sensors show promise as a proxy for nitrate measurement in automated denitrification.
- Implementing N₂O probes could enhance the automation and efficiency of biological nutrient removal processes.
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