The need for accurate and continuous monitoring of greenhouse gas (GHG) emissions from Wastewater treatment plants (WWTPs) has grown due to the complex nature of these emissions and the spatial-temporal variations in their release. Traditional point-sampling methods have limitations, such as low temporal resolution and a lack of comprehensive coverage of emissions from heterogeneous sources. These challenges underscore the necessity for more advanced and efficient monitoring systems that can provide real-time, multi-gas data. Based on these challenges, in-depth research into more effective emission monitoring systems is required.

The study (DOI: 10.1016/j.ese.2025.100554) was conducted by researchers from Radboud University in the Netherlands and published in Environmental Science and Ecotechnology in March 2025. The coherent open-path spectroscopy (COPS) system was deployed at a WWTP to monitor methane (CH₄), carbon dioxide (CO₂), and nitrous oxide (N₂O), ammonia (NH₃), carbon monoxide (CO), and water vapor (H₂O). The system, which uses an ultra-broadband mid-infrared light source, demonstrated superior detection capabilities over traditional point-sampling methods, capturing gas concentrations in real-time with high temporal resolution.

The COPS system represents a significant leap forward in emissions monitoring. Unlike conventional point-sampling techniques, the COPS system offers continuous, non-invasive monitoring over a broad spectral range (2-11.5 micrometers), allowing for the simultaneous detection of multiple gases. In the field test, the system was able to track CH₄ and CO₂ emissions above an aeration tank at a WWTP, with clear correlations between gas concentrations and aeration periods. The system also demonstrated a high level of accuracy in measuring gases such as N₂O, NH₃, and CO, with results that closely matched those from traditional commercial analyzers. One of the key advantages of the COPS system is its ability to capture emissions across a broad area, overcoming the spatial limitations of point-based measurements. This system can monitor gas emissions from multiple sources simultaneously, offering a more robust, comprehensive method for environmental monitoring. The system's ability to detect various gases in real-time with high sensitivity enhances its potential for both industrial and atmospheric emissions assessments.

Dr. Simona Cristescu, a leading expert in analytical chemistry at Radboud University, emphasizes the transformative potential of the COPS system, stating, "The ability to monitor multiple greenhouse gases simultaneously with high precision and minimal interference is a major step forward for environmental monitoring. This technology not only improves our understanding of emission patterns but also offers a scalable solution for more sustainable wastewater treatment operations."

The COPS system holds significant promise for improving emissions monitoring in a wide range of industries, especially those with complex, variable emission sources like WWTPs. By providing real-time data on multiple gases, the system can enhance emission quantification, inform mitigation strategies, and support regulatory compliance. Additionally, the continuous, non-invasive nature of the system makes it a cost-effective and efficient solution for long-term environmental monitoring. As the technology advances, it could be applied to other sectors, such as agriculture and industrial manufacturing, to further reduce environmental footprints and improve sustainability efforts.

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References

DOI

10.1016/j.ese.2025.100554

Original Source URL

https://doi.org/10.1016/j.ese.2025.100554

Funding information

This work was supported by the EU Horizon2020 program [101015825, TRIAGE Project]; the Interdisciplinary Research Platform (IRP) at the Faculty of Science of Radboud University [Project: Towards accurate detection of greenhouse gas emission from wastewater treatment plants]; and the Dutch water authorities Hoogheemraadschap de Stichtse Rijnlanden, Waterschap Rivierenland, and Hoogheemraadschap Hollands Noorderkwartier [Aquafarm 2.0].

About Environmental Science and Ecotechnology

Environmental Science and Ecotechnology (ISSN 2666-4984) is an international, peer-reviewed, and open-access journal published by Elsevier. The journal publishes significant views and research across the full spectrum of ecology and environmental sciences, such as climate change, sustainability, biodiversity conservation, environment & health, green catalysis/processing for pollution control, and AI-driven environmental engineering. The latest impact factor of ESE is 14, according to the Journal Citation Report^TM 2024.