{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T20:00:39Z","timestamp":1784836839484,"version":"3.55.0"},"reference-count":37,"publisher":"Public Library of Science (PLoS)","issue":"7","license":[{"start":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T00:00:00Z","timestamp":1784764800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["51975011"],"award-info":[{"award-number":["51975011"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:p>To address the escalating water resources consumption, the need for intelligent automation in urban sewage treatment has become imperative. However, existing ultrasonic sludge interface instruments have been found to exhibit poor environmental noise suppression and low identification accuracy of mud-water interface, thereby necessitating a new approach. This paper analyzes the problems and proposes a mud-water interface monitoring method based on extraction of ultrasonic energy peak point. The method involves an array ultrasonic system structure comprising multiple ultrasonic transmitting and receiving elements, median value average filtering to suppress peak noise interference, and interval maximum method to separate the target peak point from residual noise. The proposed method was tested using a high-precision ultrasonic probe in Beijing Ma-Fang Sewage Treatment Plant and corrected using a fault diagnosis method with 3\u03c3 threshold. Results demonstrated a high measurement accuracy with a mean deviation of less than 2% and a precision variance below \u00b10.02 m. Compared to conventional ultrasonic and optical methods, this approach exhibited superior robustness in turbid environments, fully meeting the technical requirements of sludge thickness monitoring.<\/jats:p>","DOI":"10.1371\/journal.pone.0332781","type":"journal-article","created":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T19:01:16Z","timestamp":1784833276000},"page":"e0332781","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Measurement of sludge-water interface based on adjustable peak point of ultrasonic echo energy"],"prefix":"10.1371","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-1425-4566","authenticated-orcid":true,"given":"Miao","family":"Li","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4127-2980","authenticated-orcid":true,"given":"Yang","family":"Miao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fengying","family":"Zhou","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yongqiang","family":"Yang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huan","family":"Huang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2026,7,23]]},"reference":[{"key":"pone.0332781.ref001","doi-asserted-by":"crossref","first-page":"240","DOI":"10.1016\/j.dib.2018.09.125","article-title":"Data of thematic analysis of farmer\u05f3s use behavior of recycled industrial wastewater","volume":"21","author":"L Aljerf","year":"2018","journal-title":"Data Brief"},{"key":"pone.0332781.ref002","doi-asserted-by":"crossref","first-page":"163705","DOI":"10.1016\/j.scitotenv.2023.163705","article-title":"Assessment of PCDD\/Fs formation and emission characteristics at a municipal solid waste incinerator for one year","volume":"883","author":"H Xia","year":"2023","journal-title":"Sci Total Environ"},{"key":"pone.0332781.ref003","doi-asserted-by":"crossref","first-page":"135834","DOI":"10.1016\/j.jhazmat.2024.135834","article-title":"AI-based tree modeling for multi-point dioxin concentrations in municipal solid waste incineration","volume":"480","author":"H Xia","year":"2024","journal-title":"J Hazard Mater"},{"key":"pone.0332781.ref004","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1016\/j.watres.2016.11.015","article-title":"Identification of microplastic in effluents of waste water treatment plants using focal plane array-based micro-Fourier-transform infrared imaging","volume":"108","author":"SM Mintenig","year":"2017","journal-title":"Water Res"},{"key":"pone.0332781.ref005","doi-asserted-by":"crossref","first-page":"123826","DOI":"10.1016\/j.fuel.2022.123826","article-title":"Comprehensive review on mechanism analysis and numerical simulation of municipal solid waste incineration process based on mechanical grate","volume":"320","author":"J Zhuang","year":"2022","journal-title":"Fuel"},{"key":"pone.0332781.ref006","doi-asserted-by":"crossref","first-page":"116510","DOI":"10.1016\/j.ces.2021.116510","article-title":"Automated interface detection in liquid-liquid systems using self-calibrating ultrasonic sensor","volume":"236","author":"D Mukherjee","year":"2021","journal-title":"Chem Eng Sci"},{"issue":"4","key":"pone.0332781.ref007","doi-asserted-by":"crossref","first-page":"706","DOI":"10.3390\/s17040706","article-title":"A Novel Ultrasonic Method for Liquid Level Measurement Based on the Balance of Echo Energy","volume":"17","author":"B Zhang","year":"2017","journal-title":"Sensors (Basel)"},{"issue":"6","key":"pone.0332781.ref008","doi-asserted-by":"crossref","first-page":"1351","DOI":"10.3390\/s17061351","article-title":"Acoustic Emission and Echo Signal Compensation Techniques Applied to an Ultrasonic Logging-While-Drilling Caliper","volume":"17","author":"Y Yao","year":"2017","journal-title":"Sensors (Basel)"},{"key":"pone.0332781.ref009","doi-asserted-by":"crossref","first-page":"419","DOI":"10.1016\/j.petrol.2017.09.051","article-title":"Study of the ultrasonic propagation law in the gas\u2013liquid two-phase flow of deepwater riser through numerical simulation","volume":"159","author":"Y Xu","year":"2017","journal-title":"Journal of Petroleum Science and Engineering"},{"issue":"9","key":"pone.0332781.ref010","doi-asserted-by":"crossref","first-page":"3711","DOI":"10.1007\/s10967-023-09040-x","article-title":"Study on ultrasonic flocculation combined treatment of low radioactive uranium wastewater","volume":"332","author":"T Wu","year":"2023","journal-title":"J Radioanal Nucl Chem"},{"key":"pone.0332781.ref011","doi-asserted-by":"crossref","first-page":"419","DOI":"10.1016\/j.petrol.2017.09.051","article-title":"Study of the ultrasonic propagation law in the gas\u2013liquid two-phase flow of deepwater riser through numerical simulation","volume":"159","author":"Y Xu","year":"2017","journal-title":"J Petrol Sci Eng"},{"key":"pone.0332781.ref012","doi-asserted-by":"crossref","first-page":"506","DOI":"10.1016\/j.psep.2023.05.101","article-title":"Numerical simulation modelling on whole municipal solid waste incineration process by coupling multiple software for the analysis of grate speed and air volume ratio","volume":"176","author":"J Tang","year":"2023","journal-title":"Process Safety and Environmental Protection"},{"issue":"22","key":"pone.0332781.ref013","doi-asserted-by":"crossref","first-page":"10097","DOI":"10.3390\/su172210097","article-title":"A Whole Life Cycle Mechanism Model of the Desulfurization and Denitrification Process in Municipal Solid Waste Incineration","volume":"17","author":"W Ma","year":"2025","journal-title":"Sustainability"},{"key":"pone.0332781.ref014","doi-asserted-by":"crossref","first-page":"133716","DOI":"10.1016\/j.chemosphere.2022.133716","article-title":"Dioxin emission prediction based on improved deep forest regression for municipal solid waste incineration process","volume":"294","author":"H Xia","year":"2022","journal-title":"Chemosphere"},{"issue":"5","key":"pone.0332781.ref015","doi-asserted-by":"crossref","first-page":"108314","DOI":"10.1016\/j.jece.2022.108314","article-title":"Prediction of dioxin emission from municipal solid waste incineration based on expansion, interpolation, and selection for small samples","volume":"10","author":"J Tang","year":"2022","journal-title":"J Environ Chemical Eng"},{"issue":"8","key":"pone.0332781.ref016","doi-asserted-by":"crossref","first-page":"9515","DOI":"10.1021\/acs.energyfuels.0c01718","article-title":"Controlling Shale Swelling and Fluid Loss Properties of Water-Based Drilling Mud via Ultrasonic Impregnated SWCNTs\/PVP Nanocomposites","volume":"34","author":"A Rana","year":"2020","journal-title":"Energy Fuels"},{"issue":"6","key":"pone.0332781.ref017","doi-asserted-by":"crossref","first-page":"1351","DOI":"10.3390\/s17061351","article-title":"Acoustic Emission and Echo Signal Compensation Techniques Applied to an Ultrasonic Logging-While-Drilling Caliper","volume":"17","author":"Y Yao","year":"2017","journal-title":"Sensors (Basel)"},{"key":"pone.0332781.ref018","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1016\/j.petrol.2019.01.041","article-title":"High pressure measurement of mud density and flow rate for oil and gas well construction: Making the case for X-Ray metering","volume":"177","author":"V Singhal","year":"2019","journal-title":"J Petrol Sci Eng"},{"issue":"10","key":"pone.0332781.ref019","doi-asserted-by":"crossref","first-page":"2631","DOI":"10.1002\/jum.14964","article-title":"Diagnostic Accuracy of Echo Envelope Statistical Modeling Compared to B-Mode and Power Doppler Ultrasound Imaging in Patients With Clinically Diagnosed Lateral Epicondylosis of the Elbow","volume":"38","author":"NJ Bureau","year":"2019","journal-title":"J Ultrasound Med"},{"issue":"2","key":"pone.0332781.ref020","doi-asserted-by":"crossref","first-page":"1343","DOI":"10.1007\/s12065-020-00431-7","article-title":"A novel incomplete sparse least square optimized regression model for abdominal mass detection in ultrasound images","volume":"15","author":"SS Kore","year":"2022","journal-title":"Evol Intell"},{"issue":"19","key":"pone.0332781.ref021","first-page":"5283","article-title":"Ultrasound and ionic liquid: an ideal combination for organic transformations","volume":"3","author":"G Kaur","year":"2018","journal-title":"Chemistry Select"},{"issue":"5","key":"pone.0332781.ref022","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1080\/17474124.2018.1464389","article-title":"Contrast enhanced ultrasound (CEUS) imaging of solid benign focal liver lesions","volume":"12","author":"CF Dietrich","year":"2018","journal-title":"Expert Rev Gastroenterol Hepatol"},{"key":"pone.0332781.ref023","doi-asserted-by":"crossref","first-page":"114502","DOI":"10.1016\/j.sna.2023.114502","article-title":"Acoustic underwater propulsion system based on ultrasonic disc PZT transducer","volume":"359","author":"D Kong","year":"2023","journal-title":"Sensor Actuat A-Phys"},{"key":"pone.0332781.ref024","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/j.enggeo.2019.02.011","article-title":"A new approach to the effect of sample dimensions and measurement techniques on ultrasonic wave velocity","volume":"251","author":"H Ersoy","year":"2019","journal-title":"Engineering Geology"},{"issue":"2","key":"pone.0332781.ref025","doi-asserted-by":"crossref","first-page":"1091","DOI":"10.1103\/PhysRevE.51.1091","article-title":"Generalized hydrodynamics and the acoustic modes of water: Theory and simulation results","volume":"51","author":"D Bertolini","year":"1995","journal-title":"Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics"},{"issue":"4","key":"pone.0332781.ref026","doi-asserted-by":"crossref","first-page":"743","DOI":"10.1007\/s40328-021-00356-2","article-title":"Histogram-based weighted median filtering used for noise reduction of digital elevation model data","volume":"56","author":"R Kilik","year":"2021","journal-title":"Acta Geod Geophys"},{"issue":"20","key":"pone.0332781.ref027","doi-asserted-by":"crossref","first-page":"3656","DOI":"10.3390\/w15203656","article-title":"Three-Dimensional Numerical Analysis and Operational Optimization of High-Efficiency Sedimentation Tank","volume":"15","author":"Z Ye","year":"2023","journal-title":"Water"},{"key":"pone.0332781.ref028","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1016\/j.wasman.2023.05.056","article-title":"Dioxin emission modeling using feature selection and simplified DFR with residual error fitting for the grate-based MSWI process","volume":"168","author":"H Xia","year":"2023","journal-title":"Waste Manag"},{"key":"pone.0332781.ref029","doi-asserted-by":"crossref","first-page":"133382","DOI":"10.1016\/j.fuel.2024.133382","article-title":"Emission reduction optimization of multiple flue gas pollutants in Municipal solid waste incineration power plant","volume":"381","author":"T Wang","year":"2025","journal-title":"Fuel"},{"issue":"1","key":"pone.0332781.ref030","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1007\/s10462-023-10631-z","article-title":"Deep learning models for digital image processing: a review","volume":"57","author":"R Archana","year":"2024","journal-title":"Artif Intell Rev"},{"key":"pone.0332781.ref031","doi-asserted-by":"crossref","first-page":"176241","DOI":"10.1016\/j.scitotenv.2024.176241","article-title":"Unveiling dioxin dynamics: A whole-process simulation study of municipal solid waste incineration","volume":"954","author":"H Xia","year":"2024","journal-title":"Sci Total Environ"},{"key":"pone.0332781.ref032","doi-asserted-by":"crossref","first-page":"120949","DOI":"10.1016\/j.envpol.2022.120949","article-title":"Investigation on dioxins emission characteristic during complete maintenance operating period of municipal solid waste incineration","volume":"318","author":"H Xia","year":"2023","journal-title":"Environ Pollut"},{"issue":"16","key":"pone.0332781.ref033","doi-asserted-by":"crossref","first-page":"12337","DOI":"10.3390\/su151612337","article-title":"Three-Dimensional Numerical Modeling and Analysis for the Municipal Solid-Waste Incineration of the Grate Furnace for Particulate-Matter Generation","volume":"15","author":"Y Liang","year":"2023","journal-title":"Sustainability"},{"key":"pone.0332781.ref034","doi-asserted-by":"crossref","first-page":"122960","DOI":"10.1016\/j.ces.2025.122960","article-title":"Carbon emission life cycle mechanism modelling based on coupled numerical simulation and broad latent feature fuzzy decision tree algorithm","volume":"321","author":"Z Wang","year":"2026","journal-title":"Chemical Engineering Sci"},{"key":"pone.0332781.ref035","doi-asserted-by":"crossref","first-page":"121358","DOI":"10.1016\/j.ces.2025.121358","article-title":"Modeling multi-pollutant emission concentrations in municipal solid waste incineration processes using virtual-real data-driven approach","volume":"307","author":"T Wang","year":"2025","journal-title":"Chemical Engineering Sci"},{"key":"pone.0332781.ref036","doi-asserted-by":"crossref","first-page":"127530","DOI":"10.1016\/j.eswa.2025.127530","article-title":"Furnace temperature control based on interval type-2 fuzzy broad learning system for municipal solid waste incineration process","volume":"280","author":"H Tian","year":"2025","journal-title":"Expert Systems with Applications"},{"key":"pone.0332781.ref037","doi-asserted-by":"crossref","first-page":"125015","DOI":"10.1016\/j.eswa.2024.125015","article-title":"Intelligent optimal control of furnace temperature for the municipal solid waste incineration process using multi-loop controller and particle swarm optimization","volume":"257","author":"T Wang","year":"2024","journal-title":"Expert Systems with Applications"}],"container-title":["PLOS One"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0332781","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T19:01:22Z","timestamp":1784833282000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0332781"}},"subtitle":[],"editor":[{"given":"Hailing","family":"Ma","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,7,23]]},"references-count":37,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,7,23]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0332781","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,23]]}}}