{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,7]],"date-time":"2026-05-07T07:05:12Z","timestamp":1778137512624,"version":"3.51.4"},"reference-count":46,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2022,6,26]],"date-time":"2022-06-26T00:00:00Z","timestamp":1656201600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Funds of the FCT\u2014Portuguese Foundation for Science and Technology","award":["\u00abUIDB\/04928\/2020\u00bb"],"award-info":[{"award-number":["\u00abUIDB\/04928\/2020\u00bb"]}]},{"name":"National Funds of the FCT\u2014Portuguese Foundation for Science and Technology","award":["CEECINST\/00051\/2018"],"award-info":[{"award-number":["CEECINST\/00051\/2018"]}]},{"name":"Scientific Employment Stimulus-Institutional","award":["\u00abUIDB\/04928\/2020\u00bb"],"award-info":[{"award-number":["\u00abUIDB\/04928\/2020\u00bb"]}]},{"name":"Scientific Employment Stimulus-Institutional","award":["CEECINST\/00051\/2018"],"award-info":[{"award-number":["CEECINST\/00051\/2018"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Water"],"abstract":"<jats:p>Understanding how to address today\u2019s global challenges is critical to improving corporate performance in terms of economic and environmental sustainability. In wastewater treatment systems, such an approach implies integrating efficient treatment technologies with aspects of the circular economy. In this business field, energy costs represent a large share of operating costs. This work discusses technological and management aspects leading to greater energy savings in Portuguese wastewater treatment companies. A mixed methodology, involving qualitative and quantitative aspects, for collecting and analysing data from wastewater treatment plants was used. The qualitative aspects consisted of a narrative analysis of the information available on reports and websites for 11 wastewater management companies in Portugal (e.g., technologies, treated wastewater volumes and operating costs) followed by a review of several international studies. The quantitative approach involved calculating the specific energy consumption (kWh\/m3), energy operating costs (EUR\/m3) and energy operating costs per population equivalent (EUR\/inhabitants) using data from the literature and from Portuguese companies collected from the SABI database. The results suggested that the most environmentally and economically sustainable solution is algae-based technology which might allow a reduction in energy operating costs between 0.05\u20130.41 EUR\/m3 and 15.4\u2013180.8 EUR\/inhabitants compared to activated sludge and other conventional methods. This technology, in addition to being financially advantageous, provides the ability to eliminate the carbon footprint and the valorisation of algae biomass, suggesting that this biotechnology is starting to position itself as a mandatory future solution in the wastewater treatment sector.<\/jats:p>","DOI":"10.3390\/w14132042","type":"journal-article","created":{"date-parts":[[2022,6,26]],"date-time":"2022-06-26T22:50:23Z","timestamp":1656283823000},"page":"2042","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":29,"title":["Economic Assessment of Energy Consumption in Wastewater Treatment Plants: Applicability of Alternative Nature-Based Technologies in Portugal"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4693-0804","authenticated-orcid":false,"given":"Eleonora","family":"Santos","sequence":"first","affiliation":[{"name":"Centre of Applied Research in Management and Economics, School of Management and Technology, Polytechnic Institute of Leiria, 2411-901 Leiria, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7099-0685","authenticated-orcid":false,"given":"Ant\u00f3nio","family":"Albuquerque","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering and Architecture, FibEnTech, GeoBioTec, University of Beira Interior, Cal\u00e7ada Fonte do Lameiro 6, 6200-358 Covilh\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2802-2589","authenticated-orcid":false,"given":"In\u00eas","family":"Lisboa","sequence":"additional","affiliation":[{"name":"Centre of Applied Research in Management and Economics, School of Management and Technology, Polytechnic Institute of Leiria, 2411-901 Leiria, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6349-7761","authenticated-orcid":false,"given":"Patrick","family":"Murray","sequence":"additional","affiliation":[{"name":"Shannon Applied Biotechnology Centre, Moylish Park, V94 EC5T Limerick, Ireland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7246-0346","authenticated-orcid":false,"given":"Hande","family":"Ermis","sequence":"additional","affiliation":[{"name":"Shannon Applied Biotechnology Centre, Moylish Park, V94 EC5T Limerick, Ireland"}]}],"member":"1968","published-online":{"date-parts":[[2022,6,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"70","DOI":"10.3389\/fenvs.2017.00070","article-title":"Enhancing the Energy Efficiency of Wastewater Treatment Plants through Co-digestion and Fuel Cell Systems","volume":"5","author":"Gandiglio","year":"2017","journal-title":"Front. Environ. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"114214","DOI":"10.1016\/j.enconman.2021.114214","article-title":"100% renewable wastewater treatment plants: Techno-economic assement using a modelling and optimization approach","volume":"239","author":"Campana","year":"2021","journal-title":"Energy Convers. Manage."},{"key":"ref_3","unstructured":"(2022, January 15). Aqualitrans Project. Available online: http:\/\/www.inega.gal\/informacion\/proxectos_europeos\/aqualitrans.html."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"16","DOI":"10.5004\/dwt.2009.349","article-title":"Economic and environmental assessment of small and decentralized wastewater treatment systems","volume":"4","author":"Nogueira","year":"2009","journal-title":"Desalin. Water Treat."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"399","DOI":"10.1016\/j.jclepro.2019.04.320","article-title":"Assessment of energy consumption of municipal wastewater treatment plants in China","volume":"228","author":"He","year":"2019","journal-title":"J. Clean. Prod."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1317","DOI":"10.1007\/s10811-013-0142-0","article-title":"Seasonal variation in light utilisation, biomass production and nutrient removal by wastewater microalgae in a full-scale high-rate algal pond","volume":"26","author":"Sutherland","year":"2014","journal-title":"J. Appl. Phycol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/j.ecoleng.2014.03.032","article-title":"The influence of evapotranspiration on vertical flow subsurface constructed wetland performance","volume":"67","author":"Albuquerque","year":"2014","journal-title":"Ecol. Eng."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Mesquita, C., Albuquerque, A., Amaral, L., and Nogueira, R. (2018). Effectiveness and Temporal Variation of a Full-Scale Horizontal Constructed Wetland in Reducing Nitrogen and Phosphorus from Domestic Wastewater. ChemEngineering, 2.","DOI":"10.3390\/chemengineering2010003"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"S\u00e1tiro, J., Cunha, A., Gomes, A.P., Sim\u00f5es, R., and Albuquerque, A. (2022). Optimization of Microalgae\u2013Bacteria Consortium in the Treatment of Paper Pulp Wastewater. Appl. Sci., 12.","DOI":"10.3390\/app12125799"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Viswanaathan, S., Perumal, P.K., and Sundaram, S. (2022). Integrated Approach for Carbon Sequestration and Wastewater Treatment Using Algal\u2013Bacterial Consortia: Opportunities and Challenges. Sustainability, 14.","DOI":"10.3390\/su14031075"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"135303","DOI":"10.1016\/j.scitotenv.2019.135303","article-title":"Cultivating microalgae in wastewater for biomass production, pollutant removal, and atmospheric carbon mitigation; a review","volume":"704","author":"Shahid","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"101850","DOI":"10.1016\/j.algal.2020.101850","article-title":"Improved microalgal productivity and nutrient removal through operating wastewater high rate algal ponds in series","volume":"47","author":"Sutherland","year":"2019","journal-title":"Algal Res."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"465","DOI":"10.1016\/j.watres.2013.10.036","article-title":"Capability of different microalgae species for phytoremediation processes: Wastewater tertiary treatment, CO2 bio-fixation and low cost biofuels production","volume":"49","author":"Arbib","year":"2014","journal-title":"Water Res."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1118","DOI":"10.1016\/j.scitotenv.2017.12.051","article-title":"Life cycle assessment of high rate algal ponds for wastewater treatment and resource recovery","volume":"622\u2013623","author":"Arashiro","year":"2018","journal-title":"Sci. Total Environ."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1578","DOI":"10.1002\/er.4448","article-title":"Understanding the influence of the alkaline cation K + or Na + in the regeneration efficiency of a biogas upgrading unit","volume":"43","author":"Vega","year":"2019","journal-title":"Int. J. Energy Res."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"142753","DOI":"10.1016\/j.scitotenv.2020.142753","article-title":"Biomethane production from anaerobic co-digestion at wastewater treatment plants: A critical review on development and innovations in biogas upgrading techniques","volume":"765","author":"Nguyen","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_17","unstructured":"Calderon, C., Colla, M., Jossart, J.-M., Hemelleers, N., Martin, A., Aveni, N., and Caferri, C. (2019). European Bioenergy Outlook 2019, Biogas."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"565","DOI":"10.1016\/j.jclepro.2019.02.271","article-title":"Review of technologies for bio methane production and assessment of EU transport share in 2030","volume":"222","author":"Prussi","year":"2019","journal-title":"J. Clean. Prod."},{"key":"ref_19","first-page":"143645","article-title":"Synergizing carbon capture and utilization in a biogas upgrading plant based on calcium chloride: Scaling-up and profitability analysis","volume":"758","author":"Reina","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.scitotenv.2019.07.135","article-title":"Understanding the effect of Ca and Mg ions from wastes in the solvent regeneration stage of a biogas upgrading unit","volume":"691","author":"Reina","year":"2019","journal-title":"Sci. Total Environ."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"211","DOI":"10.1016\/j.jclepro.2017.05.116","article-title":"Life Cycle Assessment of wastewater treatment systems for small communities: Activated sludge, constructed wetlands and high rate algal ponds","volume":"161","author":"Flores","year":"2017","journal-title":"J. Clean. Prod."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"538","DOI":"10.1016\/j.watres.2015.10.016","article-title":"Life cycle assessment as development and decision support tool for wastewater resource recovery technology","volume":"88","author":"Fang","year":"2016","journal-title":"Water Res."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s13399-016-0208-8","article-title":"Life cycle assessment of bio methane produced from microalgae grown in municipal wastewater","volume":"7","author":"Maga","year":"2017","journal-title":"Biomass Convers. Bioref."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"110459","DOI":"10.1016\/j.jenvman.2020.110459","article-title":"Assessing the life-cycle sustainability of algae and bacteria-based wastewater treatment systems: High-rate algae pond and sequencing batch reactor","volume":"264","author":"Kohlheb","year":"2020","journal-title":"J. Environ. Manage."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"22","DOI":"10.5004\/dwt.2009.350","article-title":"Cost-effectiveness analysis for sustainable wastewater engineering and water resources management: A case study at Minho-Lima river basins (Portugal)","volume":"4","author":"Costa","year":"2009","journal-title":"Desalin. Water Treat."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1007\/s13762-012-0119-6","article-title":"Effect of vegetation on the performance of horizontal subsurface flow constructed wetlands with lightweight expanded clay aggregates","volume":"10","author":"Mesquita","year":"2013","journal-title":"Int. J. Environ. Sci. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Santos, E., Lisboa, I., and Eug\u00e9nio, T. (2021). Economic Sustainability in Wastewater Treatment Companies: A Regional Analysis for the Iberian Peninsula. Appl. Sci., 11.","DOI":"10.3390\/app11219876"},{"key":"ref_28","unstructured":"Rego, R. (2012). Performance Analysis of the Wastewater Treatment Plants Using a Metabolism Model. [Master\u2019s Thesis, IST, University of Lisbon]."},{"key":"ref_29","first-page":"296","article-title":"Energy and environmental performance of wastewater treatment plants: A statistical approach","volume":"136","author":"Moreno","year":"2017","journal-title":"Procedia"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"6557","DOI":"10.1007\/s13762-019-02236-3","article-title":"Investigation of energy efficiency in Gebze Wastewater Treatment Plant","volume":"16","author":"Turkmenler","year":"2019","journal-title":"Int. J. Environ. Sci. Technol."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Siatou, A., Manali, A., and Gikas, P. (2020). Energy Consumption and Internal Distribution in Activated Sludge Wastewater Treatment Plants of Greece. Water, 12.","DOI":"10.3390\/w12041204"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1016\/j.watres.2018.04.067","article-title":"A systematic methodology for the robust quantification of energy efficiency at wastewater treatment plants featuring Data Envelopment Analysis","volume":"141","author":"Longo","year":"2018","journal-title":"Water Res."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"129107","DOI":"10.1016\/j.jclepro.2021.129107","article-title":"Energy performance factors in wastewater treatment plants: A review","volume":"322","author":"Cardoso","year":"2021","journal-title":"J. Clean. Prod."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"303","DOI":"10.2166\/wst.2014.521","article-title":"Wastewater treatment process impact on energy savings and greenhouse gas emissions","volume":"71","author":"Mamais","year":"2014","journal-title":"Water Sci. Technol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1016\/j.apenergy.2018.11.101","article-title":"A novel index of total oxygen demand for the comprehensive evaluation of energy consumption for urban wastewater treatment","volume":"236","author":"Luo","year":"2019","journal-title":"Appl. Energy"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2620","DOI":"10.2166\/wst.2016.390","article-title":"Operating costs and energy demand of wastewater treatment plants in Austria: Benchmarking results of the last 10 years","volume":"74","author":"Haslinger","year":"2016","journal-title":"Water Sci. Technol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"2613","DOI":"10.2166\/wst.2018.222","article-title":"Modelling the bioenergy potential of municipal wastewater treatment plants","volume":"77","author":"Schopf","year":"2018","journal-title":"Water Sci. Technol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1016\/j.wasman.2013.08.024","article-title":"Environmental & economic life cycle assessment of current & future sewage sludge to energy technologies","volume":"34","author":"Mills","year":"2014","journal-title":"Waste Manag."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1015","DOI":"10.1016\/j.biortech.2017.09.004","article-title":"Anaerobic digestion for bioenergy production: Global status, environmental and techno-economic implications, and government policies","volume":"247","author":"Khanal","year":"2018","journal-title":"Bioresour. Technol."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Baena-Moreno, F., Malico, I., and Marques, I. (2021). Promoting sustainability: Wastewater treatment plants as a source of bio methane in regions far from a high-pressure grid. the real portuguese case study. Sustainability, 13.","DOI":"10.3390\/su13168933"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.jenvman.2013.09.043","article-title":"Quantifying benefits of resource recovery from sanitation provision in a developing world setting","volume":"131","author":"Cornejo","year":"2013","journal-title":"J. Environ. Manag."},{"key":"ref_42","first-page":"171","article-title":"Assessing Environmental Impacts of Wastewater Treatment Alternatives for Small-Scale Communities","volume":"40","author":"Topkaya","year":"2011","journal-title":"CLEAN Soil Air Water"},{"key":"ref_43","unstructured":"Rozko\u0161n\u00fd, M., Kri\u0161ka, M., \u0160\u00e1lek, J., Bod\u00edk, I., and Isteni\u010d, D. (2014). Natural Technologies of Wastewater Treatment, Global Water Partnership Central and Eastern Europe."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1016\/S0925-8574(03)00007-7","article-title":"Assessing the environmental impact of two options for small-scale wastewater treatment: Comparing a reedbed and an aerated biological filter using a life cycle approach","volume":"20","author":"Dixon","year":"2003","journal-title":"Ecol. Eng."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1016\/j.scitotenv.2016.02.073","article-title":"Beyond the conventional life cycle inventory in wastewater treatment plants","volume":"553","author":"Amores","year":"2016","journal-title":"Sci. Total Environ."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"111337","DOI":"10.1016\/j.jenvman.2020.111337","article-title":"Alternative water supply solutions: China\u2019s South-to-North-water-diversion in Jinan","volume":"276","author":"Liu","year":"2020","journal-title":"J. Environ. Manag."}],"container-title":["Water"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4441\/14\/13\/2042\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:38:35Z","timestamp":1760139515000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4441\/14\/13\/2042"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,6,26]]},"references-count":46,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2022,7]]}},"alternative-id":["w14132042"],"URL":"https:\/\/doi.org\/10.3390\/w14132042","relation":{},"ISSN":["2073-4441"],"issn-type":[{"value":"2073-4441","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,6,26]]}}}