Decoding the Lifecycle Dynamics of Aerobic Granular Sludge: Quantifying Mechanisms of Stability and Disintegration

Decoding the Lifecycle Dynamics of Aerobic Granular Sludge: Quantifying Mechanisms of Stability and Disintegration | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Decoding the Lifecycle Dynamics of Aerobic Granular Sludge: Quantifying Mechanisms of Stability and Disintegration Fang Ma, Guanhan Meng, Leyao Xing, Weixu Song, Ran Sui, Minghan Xu, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6831113/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Aerobic granular sludge (AGS) offers a compact and energy-efficient alternative to conventional activated sludge systems. Yet, instability under long-term operation remains a critical barrier to its widespread deployment. The mechanisms governing granule formation and disintegration are not fully resolved, largely due to static, reductionist studies that overlook AGS’s temporal dynamics. Here, we present a time-resolved, multiscale framework that tracks AGS evolution through its natural “small-large-small” granule size cycle, treating size as a proxy for developmental stage. This approach captures the dynamic transitions of AGS across multiple growth and decay phases, revealing that stable granule formation requires synergistic coupling between filamentous scaffolds ( Thiothrix abundance, β = 0.843), autotrophic respiration (β = 0.744), and protein-rich extracellular polymeric substances (EPS; PN/PS ratio, β = 0.791). These interactions establish structural cohesion through metabolic-structural feedback. When critical thresholds are not met (e.g., Thiothrix < 18.7%, PN/PS ratio < 3.5), granulation fails. Disintegration initiates via a cascading failure process, driven by internal cavity expansion (β = 0.876), EPS depletion (LB-EPS < 15.3 mg/g VSS), and reduced viscoelastic resistance (viscosity < 215 Pa·s). These transitions coincide with microbial succession and altered EPS synthesis under oxygen gradients. A strong inverse correlation between granule integrity and mass transfer efficiency (β = -0.753, p < 0.001) exposes a trade-off between structural stability and nutrient diffusion. In parallel with these mechanistic insights into AGS lifecycle transitions, we developed predictive models that link structural traits to pollutant removal performance, offering a theoretical framework for optimizing long-term reactor performance. Together, these mechanistic insights and predictive models provide a unified framework for understanding and controlling AGS lifecycle transitions, marking a significant step forward in the rational design of stable, high-performance wastewater treatment systems. Earth and environmental sciences/Environmental sciences/Environmental impact Biological sciences/Biotechnology/Environmental biotechnology Full Text Additional Declarations There is NO Competing Interest. Supplementary Files Supplementary.docx Supplementary Information: Methodological Details and Extended Data for Aerobic Granular Sludge Lifecycle Study Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6831113","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":470639077,"identity":"97ffc193-dcae-4407-9118-c162874895d6","order_by":0,"name":"Fang 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Yet, instability under long-term operation remains a critical barrier to its widespread deployment. The mechanisms governing granule formation and disintegration are not fully resolved, largely due to static, reductionist studies that overlook AGS\u0026rsquo;s temporal dynamics. Here, we present a time-resolved, multiscale framework that tracks AGS evolution through its natural \u0026ldquo;small-large-small\u0026rdquo; granule size cycle, treating size as a proxy for developmental stage. This approach captures the dynamic transitions of AGS across multiple growth and decay phases, revealing that stable granule formation requires synergistic coupling between filamentous scaffolds (\u003cem\u003eThiothrix\u003c/em\u003e abundance, β\u0026thinsp;=\u0026thinsp;0.843), autotrophic respiration (β\u0026thinsp;=\u0026thinsp;0.744), and protein-rich extracellular polymeric substances (EPS; PN/PS ratio, β\u0026thinsp;=\u0026thinsp;0.791). These interactions establish structural cohesion through metabolic-structural feedback. When critical thresholds are not met (e.g., \u003cem\u003eThiothrix\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;18.7%, PN/PS ratio\u0026thinsp;\u0026lt;\u0026thinsp;3.5), granulation fails. Disintegration initiates via a cascading failure process, driven by internal cavity expansion (β\u0026thinsp;=\u0026thinsp;0.876), EPS depletion (LB-EPS\u0026thinsp;\u0026lt;\u0026thinsp;15.3 mg/g VSS), and reduced viscoelastic resistance (viscosity\u0026thinsp;\u0026lt;\u0026thinsp;215 Pa\u0026middot;s). These transitions coincide with microbial succession and altered EPS synthesis under oxygen gradients. A strong inverse correlation between granule integrity and mass transfer efficiency (β = -0.753, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) exposes a trade-off between structural stability and nutrient diffusion. In parallel with these mechanistic insights into AGS lifecycle transitions, we developed predictive models that link structural traits to pollutant removal performance, offering a theoretical framework for optimizing long-term reactor performance. Together, these mechanistic insights and predictive models provide a unified framework for understanding and controlling AGS lifecycle transitions, marking a significant step forward in the rational design of stable, high-performance wastewater treatment systems.\u003c/p\u003e","manuscriptTitle":"Decoding the Lifecycle Dynamics of Aerobic Granular Sludge: Quantifying Mechanisms of Stability and Disintegration","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-27 07:08:26","doi":"10.21203/rs.3.rs-6831113/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"4d3c089c-80ab-4218-a974-f6ee273cf9ea","owner":[],"postedDate":"June 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":49980403,"name":"Earth and environmental sciences/Environmental sciences/Environmental impact"},{"id":49980404,"name":"Biological sciences/Biotechnology/Environmental biotechnology"}],"tags":[],"updatedAt":"2025-06-27T07:08:26+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-27 07:08:26","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6831113","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6831113","identity":"rs-6831113","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}