Locating and quantifying CH<sub>4</sub> sources within a wastewater treatment plant based on mobile measurements
<p>Wastewater treatment plants (WWTPs) are substantial contributors of greenhouse gas (GHG) emissions because of the high production of methane (<span class="inline-formula">CH<sub>4</sub></span>) and nitrous oxide (<span class="inline-formula">...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2025-04-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/25/4571/2025/acp-25-4571-2025.pdf |
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| Summary: | <p>Wastewater treatment plants (WWTPs) are substantial contributors of greenhouse gas (GHG) emissions because of the high production of methane (<span class="inline-formula">CH<sub>4</sub></span>) and nitrous oxide (<span class="inline-formula">N<sub>2</sub>O</span>). A typical WWTP complex contains multiple functional areas that are potential sources of GHG emissions. Accurately quantifying GHG emissions from these sources is challenging due to the inaccuracy of activity data, the ambiguity of emission sources, and the absence of monitoring standards. Locating and quantifying WWTP emission sources using a measurement-based GHG emission quantification method is crucial for evaluating and improving traditional emission inventories. In this study, <span class="inline-formula">CH<sub>4</sub></span> mobile measurements were conducted within a WWTP complex in the summer and winter of 2023. We utilized a multi-source Gaussian plume model combined with a genetic algorithm inversion framework, designed to locate major sources within the plant and quantify the corresponding <span class="inline-formula">CH<sub>4</sub></span> emission fluxes. We identified 13 main sources in the plant and estimated plant-scale <span class="inline-formula">CH<sub>4</sub></span> emission fluxes of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">68.78</mn><mo>±</mo><mn mathvariant="normal">17.40</mn><mspace width="0.125em" linebreak="nobreak"/><mrow class="unit"><mi mathvariant="normal">kg</mi><mspace width="0.125em" linebreak="nobreak"/><msup><mi mathvariant="normal">h</mi><mrow><mo>-</mo><mn mathvariant="normal">1</mn></mrow></msup></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="99pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="ef906cc21a5667213f8531e4b749d8c1"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-25-4571-2025-ie00001.svg" width="99pt" height="15pt" src="acp-25-4571-2025-ie00001.png"/></svg:svg></span></span> (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">603.33</mn><mo>±</mo><mn mathvariant="normal">152.66</mn><mspace width="0.125em" linebreak="nobreak"/><mrow class="unit"><mi mathvariant="normal">t</mi><mspace width="0.125em" linebreak="nobreak"/><msup><mi mathvariant="normal">a</mi><mrow><mo>-</mo><mn mathvariant="normal">1</mn></mrow></msup></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="102pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="46b276ab6633a889909eec01ef7f111e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-25-4571-2025-ie00002.svg" width="102pt" height="14pt" src="acp-25-4571-2025-ie00002.png"/></svg:svg></span></span>) for the summer and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M10" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">47.76</mn><mo>±</mo><mn mathvariant="normal">21.39</mn><mspace linebreak="nobreak" width="0.125em"/><mrow class="unit"><mi mathvariant="normal">kg</mi><mspace width="0.125em" linebreak="nobreak"/><msup><mi mathvariant="normal">h</mi><mrow><mo>-</mo><mn mathvariant="normal">1</mn></mrow></msup></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="99pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="69c4f87a99015a49ffc136369352b582"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-25-4571-2025-ie00003.svg" width="99pt" height="15pt" src="acp-25-4571-2025-ie00003.png"/></svg:svg></span></span> (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M11" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">418.95</mn><mo>±</mo><mn mathvariant="normal">187.59</mn><mspace linebreak="nobreak" width="0.125em"/><mrow class="unit"><mi mathvariant="normal">t</mi><mspace linebreak="nobreak" width="0.125em"/><msup><mi mathvariant="normal">a</mi><mrow><mo>-</mo><mn mathvariant="normal">1</mn></mrow></msup></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="102pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="fa9d09ddbcfefa0723e932a8c199a5df"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-25-4571-2025-ie00004.svg" width="102pt" height="14pt" src="acp-25-4571-2025-ie00004.png"/></svg:svg></span></span>) for the winter. The predominant sources of <span class="inline-formula">CH<sub>4</sub></span> emissions were the screen and primary clarifier, contributing 55 % and 67 % to the total emissions in summer and winter, respectively. The comparison revealed that summer <span class="inline-formula">CH<sub>4</sub></span> emissions were 2.8 times higher than inventory estimates, while winter emissions were twice the inventory values. This study demonstrated that mobile measurements, combined with the multi-source Gaussian plume inversion framework, are a powerful tool to locate and quantify GHG sources at a complex site, with the potential for further refinement to accommodate different types of factories and gas species.</p> |
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| ISSN: | 1680-7316 1680-7324 |