{"id":18069,"date":"2024-10-30T15:11:56","date_gmt":"2024-10-30T19:11:56","guid":{"rendered":"https:\/\/aecom.com\/blog\/?p=18069"},"modified":"2024-10-30T15:25:17","modified_gmt":"2024-10-30T19:25:17","slug":"the-fine-balancing-act-of-tackling-n2o-emissions","status":"publish","type":"post","link":"https:\/\/aecom.com\/blog\/the-fine-balancing-act-of-tackling-n2o-emissions\/","title":{"rendered":"The fine balancing act of tackling N2O emissions"},"content":{"rendered":"\n

While at the Water Environment Federation\u2019s Technical Exhibition and Conference 2024 (<\/em>WEFTEC 2024<\/em><\/a>), the\u00a0largest conference of its kind in North America, Anna moderated a conversation around an urgent, emerging environmental issue: nitrous oxide (N2<\/sub>O) emissions.<\/em><\/p>\n\n\n\n

During her panel, \u201cN2<\/sub>O Unmasked: Understanding and Taming Emissions,\u201d she and industry leaders discussed how wastewater treatment plants are a significant source of N2<\/sub>O \u2014 a potent greenhouse gas (GHG) with a global warming potential nearly 300 times greater than carbon dioxide <\/em>(CO2<\/sub>).<\/em><\/p>\n\n\n\n

As the discussions unfolded, it became clear that N2<\/sub>O emissions, though still an emerging climate challenge, require urgent action. Below, Anna reflects on learnings from her panel, and how the industry can respond to the crisis of N2<\/sub>O emissions.<\/em><\/p>\n\n\n\n

\n\n\n\n

Understanding N2<\/sub>O and the interdependencies between greenhouse gases<\/strong><\/p>\n\n\n\n

At the heart of the conversation was our approach to the challenge of N2<\/sub>O in wastewater treatment. N2<\/sub>O, more commonly known as laughing gas, is the largest GHG contributor for treating wastewater biologically, according to emerging science. We\u2019ve reached a point where the industry understands how to measure N2<\/sub>O emissions, but the next step is mitigation.<\/p>\n\n\n\n

Those who presented at WEFTEC have been studying mitigation strategies through models and full-scale campaigns. A major focus of the discussion was on the models currently being used to identify potential strategies. During this interactive session, we spent time discussing the most important questions. For instance: Is it better to add external carbon in order to reduce N2<\/sub>O emissions? And are the results of the model reliable enough for us to take action?<\/p>\n\n\n\n

The balancing conundrum<\/strong><\/p>\n\n\n\n

Unlike pollutants such as methane and sulfur dioxide, N2<\/sub>O is a stable molecule that does not easily react with other compounds in the atmosphere or break down naturally. Therefore, minimizing its release is imperative.<\/p>\n\n\n\n

Looking at the models discussed during the panel, carbon fractions, dissolved oxygen levels and process configurations we choose \u2014 whether it\u2019s complete mix systems, plug flow systems, or carousel systems \u2014 all have an impact on how much N2<\/sub>O is produced. Each system behaves differently, not only in how it handles nitrogen removal but also in how it affects the release of N2<\/sub>O. In other words, there is a delicate balance we must strike when reducing GHG emissions in our work, as an attempt to reduce one GHG may result in the higher net release of GHGs.<\/p>\n\n\n\n

Quantify, understand and mitigate: Reconsidering the order of actions<\/strong><\/p>\n\n\n\n

A particularly resonant message from the panel discussion was that following a strict sequence of quantify<\/em>, understand<\/em>, mitigate<\/em> won\u2019t support our urgent need to tackle this issue. Although, traditionally, these steps are performed in sequence, when it comes to N2<\/sub>O emissions, it is critical to realize that we can \u2014 and should \u2014 perform these steps in parallel. This shift in thinking is essential for accelerating our response to the climate crisis.<\/p>\n\n\n\n

While the models we use to predict N2<\/sub>O emissions still require calibration, the consensus is that they are reliable enough to guide action. This marks a turning point. We don\u2019t need to wait for perfect understanding before we act. There is enough data today to influence design and operational decisions that can significantly reduce N2<\/sub>O emissions.<\/p>\n\n\n\n

For example, in New Zealand, AECOM has carried out N2<\/sub>O and CH4<\/sub> modelling for both operational and embodied emissions to inform client decision-making regarding which new wastewater treatment process they should construct and operate. Working across the global AECOM network to inform a practical emissions monitoring plan, we were able to yield recommendations regarding installation of measurement devices to identify emissions hot spots, then feedback to plant controls to ultimately pre-empt and reduce emissions where feasible.<\/p>\n\n\n\n

The role of engineers in environmental health<\/strong><\/p>\n\n\n\n

Beyond N2<\/sub>O emissions, my experience at WEFTEC reminded me of the broader responsibility we have as wastewater engineers. Our work directly impacts the global biogeochemical cycle \u2014 the way nutrients like nitrogen and phosphorus move through the environment.<\/p>\n\n\n\n

Oftentimes, human activities \u2014 even well-intentioned ones like building levees for flood protection \u2014 can have unintended negative consequences on ecosystems, such as the destruction of aquatic habitats. It\u2019s a powerful reminder that the choices we make as engineers don\u2019t just affect the immediate challenges we\u2019re solving but also have ripple effects across the entire environment.<\/p>\n\n\n\n

On the road to tackling N2<\/sub>O emissions, even with blind spots<\/strong><\/p>\n\n\n\n

Our discussions related to N2<\/sub>O emissions at WEFTEC 2024 underscored the fact that while we still have so many questions without concrete answers, there are a few things we know for sure, as well as specific actions we can take.<\/p>\n\n\n\n

First, when our models are not calibrated with detailed measurements, we know they are appropriate for trends. We also know that while our understanding of managing N2<\/sub>O is an iterative process, we can make calculated decisions by carefully balancing trade-offs \u2014 should we be accepting higher N2<\/sub>O emissions where the approach reduces overall GHG emissions, for instance, versus adding reactor volume using concrete structures with their own embedded carbon footprint to reduce N2<\/sub>O emissions.<\/p>\n\n\n\n

Our ability to balance these factors will determine the health of both our water systems and the planet as a whole.<\/p>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

During her panel, \u201cN2O Unmasked: Understanding and Taming Emissions,\u201d at WEFTEC 2024, Anna and industry leaders discussed how wastewater treatment plants are a significant source of N2O \u2014 a potent greenhouse gas with a global warming potential nearly 300 times greater than CO2.<\/p>\n","protected":false},"author":712,"featured_media":18070,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[171],"tags":[1984,6675,6620,108],"yst_prominent_words":[2516,4997,4995,3475,2311,2211,699],"class_list":["post-18069","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-water","tag-environment","tag-n2o-emissions","tag-wastewater","tag-water"],"acf":[],"_links":{"self":[{"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/posts\/18069","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/users\/712"}],"replies":[{"embeddable":true,"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/comments?post=18069"}],"version-history":[{"count":3,"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/posts\/18069\/revisions"}],"predecessor-version":[{"id":18077,"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/posts\/18069\/revisions\/18077"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/media\/18070"}],"wp:attachment":[{"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/media?parent=18069"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/categories?post=18069"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/tags?post=18069"},{"taxonomy":"yst_prominent_words","embeddable":true,"href":"https:\/\/aecom.com\/blog\/wp-json\/wp\/v2\/yst_prominent_words?post=18069"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}