{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,7]],"date-time":"2026-03-07T12:05:39Z","timestamp":1772885139644,"version":"3.50.1"},"reference-count":39,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,3,1]],"date-time":"2025-03-01T00:00:00Z","timestamp":1740787200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sustainability"],"abstract":"<jats:p>The efficiency of wastewater treatment systems must be reflected in the removal of the pollutant load from the influent and the optimal energy performance of electrical equipment. Wastewater Treatment Plants (WWTPs) are part of the Intensive Energy Consumption Management System (SGCIE) and are therefore subject to mandatory energy audits. This article aims to assess the impact of an energy audit in a WWTP, according to ISO 50001:2018 and the Plan-Do-Check-Act (PDCA) methodology, to identify and quantify both persistent and transient energy inefficiencies. According to the results, the energy audit contributed to an approximate 10.8% reduction in electrical energy consumption. During the assessment, several challenges were identified that may compromise the effectiveness of audits in improving energy performance. The complexity of the treatment model, aging infrastructure and equipment, the lack of real-time data, and a limited number of indicators hinder the proper management of inefficiency phenomena, particularly transient ones.<\/jats:p>","DOI":"10.3390\/su17052145","type":"journal-article","created":{"date-parts":[[2025,3,3]],"date-time":"2025-03-03T03:22:44Z","timestamp":1740972164000},"page":"2145","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Energy Audit in Wastewater Treatment Plant According to ISO 50001: Opportunities and Challenges for Improving Sustainability"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1595-9591","authenticated-orcid":false,"given":"Francisco","family":"Esteves","sequence":"first","affiliation":[{"name":"Departamento de Engenharias, Universidade de Tr\u00e1s-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0419-7280","authenticated-orcid":false,"given":"Jos\u00e9","family":"Carlos Cardoso","sequence":"additional","affiliation":[{"name":"Departamento de Engenharias, Universidade de Tr\u00e1s-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal"},{"name":"CITAB\u2014Centre for the Research and Technology of Agro-Environmental and Biological Sciences, 5000-801 Vila Real, Portugal"}]},{"given":"S\u00e9rgio","family":"Leit\u00e3o","sequence":"additional","affiliation":[{"name":"Departamento de Engenharias, Universidade de Tr\u00e1s-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal"},{"name":"INESC TEC-INESC Technology and Science, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3224-4926","authenticated-orcid":false,"given":"Eduardo J. Solteiro","family":"Pires","sequence":"additional","affiliation":[{"name":"Departamento de Engenharias, Universidade de Tr\u00e1s-os-Montes e Alto Douro, 5000-811 Vila Real, Portugal"},{"name":"INESC TEC-INESC Technology and Science, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,3,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Kumar, R., Kumar, K., Singh, R., S\u00e1, J.C., Carvalho, S., and Santos, G. (2023). Modeling Environmentally Conscious Purchase Behavior: Examining the Role of Ethical Obligation and Green Self-Identity. Sustainability, 15.","DOI":"10.3390\/su15086426"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"89","DOI":"10.12776\/qip.v27i3.1928","article-title":"Technology Innovation to Apply the Freecycle Concept: Background, Evolution and Technological Solutions","volume":"27","author":"Santos","year":"2023","journal-title":"Qual. Innov. 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