{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T23:49:29Z","timestamp":1779925769719,"version":"3.53.1"},"reference-count":101,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2022,6,21]],"date-time":"2022-06-21T00:00:00Z","timestamp":1655769600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The entire water cycle is contaminated with largely undetected micropollutants, thus jeopardizing wastewater treatment. Currently, monitoring methods that are used by wastewater treatment plants (WWTP) are not able to detect these micropollutants, causing negative effects on aquatic ecosystems and human health. In our case study, we took collective samples around different treatment stages (aeration tank, membrane bioreactor, ozonation) of a WWTP and analyzed them via Deep-UV laser-induced Raman and fluorescence spectroscopy (LIRFS) in combination with a CNN-based AI support. This process allowed us to perform the spectra recognition of selected micropollutants and thus analyze their reliability. The results indicated that the combination of sensitive fluorescence measurements with very specific Raman measurements, supplemented with an artificial intelligence, lead to a high information gain for utilizing it as a monitoring purpose. Laser-induced Raman spectroscopy reaches detections limits of alert pharmaceuticals (carbamazepine, naproxen, tryptophan) in the range of a few \u00b5g\/L; naproxen is detectable down to 1 \u00d7 10\u22124 mg\/g. Furthermore, the monitoring of nitrate after biological treatment using Raman measurements and AI support showed a reliable assignment rate of over 95%. Applying the fluorescence technique seems to be a promising method in observing DOC changes in wastewater, leading to a correlation coefficient of R2 = 0.74 for all samples throughout the purification processes. The results also showed the influence of different extraction points in a cleaning stage; therefore, it would not be sensible to investigate them separately. Nevertheless, the interpretation suffers when many substances interact with one another and influence their optical behavior. In conclusion, the results that are presented in our paper elucidate the use of LIRFS in combination with AI support for online monitoring.<\/jats:p>","DOI":"10.3390\/s22134668","type":"journal-article","created":{"date-parts":[[2022,6,22]],"date-time":"2022-06-22T04:12:01Z","timestamp":1655871121000},"page":"4668","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":25,"title":["Possibilities of Real Time Monitoring of Micropollutants in Wastewater Using Laser-Induced Raman &amp; Fluorescence Spectroscopy (LIRFS) and Artificial Intelligence (AI)"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4387-4712","authenticated-orcid":false,"given":"Claudia","family":"Post","sequence":"first","affiliation":[{"name":"Department of Engineering Geology and Hydrogeology, RWTH Aachen University, Lochnerstr. 4-20, 52064 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Niklas","family":"Heyden","sequence":"additional","affiliation":[{"name":"Department of Engineering Geology and Hydrogeology, RWTH Aachen University, Lochnerstr. 4-20, 52064 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andr\u00e9","family":"Reinartz","sequence":"additional","affiliation":[{"name":"Department of Engineering Geology and Hydrogeology, RWTH Aachen University, Lochnerstr. 4-20, 52064 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aaron","family":"Foerderer","sequence":"additional","affiliation":[{"name":"Institute of Geomechanics and Underground Technology, RWTH Aachen University, Mies-van-der-Rohe-Stra\u00dfe 1, 52074 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Simon","family":"Bruelisauer","sequence":"additional","affiliation":[{"name":"Independent Researcher, Altburgstrasse 45, 8105 Regensdorf, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1157-976X","authenticated-orcid":false,"given":"Volker","family":"Linnemann","sequence":"additional","affiliation":[{"name":"Institute of Environmental Engineering (ISA), RWTH Aachen University, Krefelder Str. 299, 52070 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0403-9979","authenticated-orcid":false,"given":"William","family":"Hug","sequence":"additional","affiliation":[{"name":"Photon Systems Inc., 1512 Industrial Park St., Covina, CA 91722-3417, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Florian","family":"Amann","sequence":"additional","affiliation":[{"name":"Department of Engineering Geology and Hydrogeology, RWTH Aachen University, Lochnerstr. 4-20, 52064 Aachen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,6,21]]},"reference":[{"key":"ref_1","first-page":"56","article-title":"Analytik von priorit\u00e4ren Stoffen in Abwasserproben\u2014Eine wichtige Voraussetzung f\u00fcr eine Bestandsaufnahme in deutschen Kl\u00e4ranlagen","volume":"3","author":"Sacher","year":"2018","journal-title":"Mitt. Umweltchem. \u00d6kotoxikol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"619","DOI":"10.1016\/j.scitotenv.2013.12.065","article-title":"A review on the occurrence of micropollutants in the aquatic environment and their fate and removal during wastewater treatment","volume":"473\u2013474","author":"Luo","year":"2014","journal-title":"Sci. Total Environ."},{"key":"ref_3","unstructured":"Umweltbundesamt (2018). Recommendations for reducing micropollutants in waters. German Environment Agency Section II, Umweltbundesamt."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.envint.2018.11.038","article-title":"Environmentally-related contaminants of high concern: Potential sources and analytical modalities for detection, quantification, and treatment","volume":"122","author":"Rasheed","year":"2019","journal-title":"Environ. Int."},{"key":"ref_5","unstructured":"Loos, R., Negr\u00e3o De Carvalho, R., Comero, S., Conduto, A.D., Lettieri, G.M.T., Locoro, G., Paracchini, B., Tavazzi, S., Gawlik, B., and Blaha, L. (2012). EU Wide Monitoring Survey on Waste Water Treatment Plant Effluents, Publications Office of the European Union. EUR 25563 EN, JRC76400."},{"key":"ref_6","unstructured":"(2022, April 22). WFD Directive 2000\/60\/EC of the European Parliament and of the Council of 23 October 2000 Establishing a Framework for Community Action in the Field of Water Policy. Available online: https:\/\/eur-lex.europa.eu\/resource.html?uri=cellar:5c835afb-2ec6-4577-bdf8-756d3d694eeb.0004.02\/DOC_1&format=PDF."},{"key":"ref_7","unstructured":"(2022, April 22). Directive 2008\/105\/EC Environmental Quality Standards (EQS) Applicable to Surface Water, Available online: https:\/\/www.legislation.gov.uk\/eudr\/2008\/105\/contents."},{"key":"ref_8","unstructured":"(2022, June 14). LANUV NRW Untersuchungen zum Eintrag und zur Elimination Gef\u00e4hrlicher Stoffe in Kl\u00e4ranlagen. 2006, Teil 2. Available online: https:\/\/scholar.google.com\/scholar?hl=en&as_sdt=0%2C5&q=LANUV+NRW+Investigations+on+the+input+and+elimination+of+hazardous+substances+in+sewage+treatment+plants&btnG=."},{"key":"ref_9","unstructured":"Umweltbundesamt (2022, June 14). Ma\u00dfnahmen zur Verminderung des Eintrages von Mikroschadstoffen in die Gew\u00e4sser\u2014Phase 2. Texte 60. Available online: https:\/\/www.umweltbundesamt.de\/sites\/default\/files\/medien\/377\/publikationen\/mikroschadstoffen_in_die_gewasser-phase_2.pdf2016."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.iswcr.2015.03.002","article-title":"Emerging pollutants in the environment: A challenge for water resource management","volume":"3","author":"Geissen","year":"2015","journal-title":"Int. Soil Water Conserv. Res."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Wanda, E., Nyoni, H., Mamba, B., and Msagati, T. (2017). Occurrence of emerging micropollutants in water systems in Gauteng, Mpumalanga, and North West Provinces, South Africa. Int. J. Environ. Res. Public. Health, 14.","DOI":"10.3390\/ijerph14010079"},{"key":"ref_12","unstructured":"Varjani, S., Pandey, A., Tyagi, R.D., Ngo, H.H., and Larroche, C. (2020). Chapter 4\u2014Methods for the analysis of micro-pollutants. Current Developments in Biotechnology and Bioengineering, Elsevier."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1072","DOI":"10.1126\/science.1127291","article-title":"The challenge of micropollutants in aquatic systems","volume":"313","author":"Schwarzenbach","year":"2006","journal-title":"Science"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Kumar, N.M., Sudha, M.C., Damodharam, T., and Varjani, S. (2020). Micro-pollutants in surface water: Impacts on the aquatic environment and treatment technologies. Current Developments in Biotechnology and Bioengineering, Elsevier. Chapter 3.","DOI":"10.1016\/B978-0-12-819594-9.00003-6"},{"key":"ref_15","unstructured":"Wichern, M., and Heinz, E. (2022, June 14). Abwassertechnisches Laborpraktikum \u201cForschungspraktikum Siedlungswasserwirtschaft\u201d. Lehrstuhl f\u00fcr Siedlungswasserwirtschaft und Umwelttechnik, Ruhr Universit\u00e4t Bochum. Abwassertechnisches Laborpraktikum Forschungspraktikum Siedlungswasserwirtschaft\u2014PDF Free Download. Available online: docplayer.org."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1016\/j.scitotenv.2017.09.278","article-title":"Understanding the sorption and biotransformation of organic micropollutants in innovative biological wastewater treatment technologies","volume":"615","author":"Alvarino","year":"2017","journal-title":"Sci. Total Environ."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Chavoshani, A., Hashemi, A., Amin, M.M., and Ameta, S.C. (2020). Micropollutants and Challenges: Emerging in the Aquatic Environments and Treatment Processes, Elsevier. Chapter 1.","DOI":"10.1016\/B978-0-12-818612-1.00001-5"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1170","DOI":"10.1007\/s11270-013-1770-3","article-title":"A Review of pharmaceuticals and endocrine-disrupting compounds: Sources, effects, removal, and detections","volume":"224","author":"Tijani","year":"2013","journal-title":"Water Air Soil Pollut."},{"key":"ref_19","unstructured":"IKSR (2010). Auswertungsbericht Biozide und Korrosionsschutzmittel. Nr. 183, Internationale Kommission zum Schutze des Rheins."},{"key":"ref_20","unstructured":"Abegglen, C., Escher, B., Hollender, J., Koepke, S., Ort, C., Peter, A., Siegrist, H., von Gunten, U., Zimmermann, S.G., and Koch, M. (2022, April 04). Ozonung von Gereinigtem Abwasser. Schlussbericht Pilotversuch Regensdorf. Studie der Eawag im Auftrag des BAFU und des AWEL. Eidgen\u00f6ssische Anstalt f\u00fcr Wasserversorgung, Abwasserreinigung und Gew\u00e4sserschutz. Z\u00fcrich. Available online: http:\/\/spurenstoffelimination.de\/files\/Ozonung_Abwasser_Schlussbericht_Regensdorf.pdf."},{"key":"ref_21","unstructured":"Miehe, U. (2016). Wirksamkeit technischer Barrieren zur Entfernung von anthropogenen Spurenstoffen\u2014Kl\u00e4ranlagen und Raumfilt. [Ph.D. Dissertation, Technischen Universit\u00e4t Berlin]."},{"key":"ref_22","unstructured":"B\u00f6hler, M., and Siegrist, H. (2016). Aktivkohledosierung in den Zulauf zur Flockungs-Sandfiltration Kl\u00e4ranlage Kloten\/Opfikon\u2014Grosstechnische Umsetzung im Rahmen erg\u00e4nzender Untersuchungen zum MicroPoll-Projekt. DWA-Seminar Weitergehende Abwasserreinigung. Bonn, 18.01.2011. Ma\u00dfnahmen zur Verminderung des Eintrages von Mikroschadstoffen in die Gew\u00e4sser\u2014Phase 2, UBA. Texte 60\/2016."},{"key":"ref_23","unstructured":"Gr\u00fcnebaum, T. (2016). Elimination von Arzneimittelr\u00fcckst\u00e4nden in kommunalen Kl\u00e4ranlagen. Elimination von Arzneimitteln und organischen Spurenstoffen: Entwicklung von Konzeptionen und innovativen, kosteng\u00fcnstigen Reinigungsverfahren. Schlussbericht Phase 1. D\u00fcsseldorf: Ministerium f\u00fcr Klimaschutz, Umwelt, Landwirtschaft, Natur- und Verbraucherschutz des Landes Nordrhein-Westfalen. Ma\u00dfnahmen zur Verminderung des Eintrages von Mikroschadstoffen in die Gew\u00e4sser\u2014Phase 2, UBA. Texte 60\/2016."},{"key":"ref_24","unstructured":"Bornemann, C., Erbe, V., Hachenberg, M., Kolisch, G., Osthoff, T., and Taudien, Y. (2016). Einsatz von Pulveraktivkohle in vorhandene Flockungsfiltrationsanlagen am Beispiel der Kl\u00e4ranlage Buchenhofen. Tagungsband, Gesellschaft zur F\u00f6rderung der Siedlungswasserwirtschaft an der RWTH Aachen (45. Essener Tagung f\u00fcr Wasser- und Abfallwirtschaft). Ma\u00dfnahmen zur Verminderung des Eintrages von Mikroschadstoffen in die Gew\u00e4sser\u2014Phase 2, UBA. Texte 60\/2016."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.scitotenv.2006.04.010","article-title":"Chronic aquatic environmental risks from exposure to human pharmaceuticals","volume":"367","author":"Crane","year":"2006","journal-title":"Sci. Total Environ."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"9549","DOI":"10.1073\/pnas.1321082111","article-title":"Organic chemicals jeopardize the health of freshwater ecosystems on the continental scale","volume":"111","author":"Malaj","year":"2014","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1016\/j.watres.2015.09.023","article-title":"Spoilt for choice: A critical review on the chemical and biological assessment of current wastewater treatment technologies","volume":"87","author":"Prasse","year":"2015","journal-title":"Water Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"437","DOI":"10.1016\/j.chemosphere.2018.10.123","article-title":"Ozonation of valsartan: Structural elucidation and environmental properties of transformation products","volume":"216","author":"Diehle","year":"2019","journal-title":"Chemosphere"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1016\/j.microc.2013.04.014","article-title":"Occurrence, transportation, monitoring and treatment of emerging micro-pollutants in waste water \u2014 A review from global views","volume":"110","author":"Jiang","year":"2013","journal-title":"Microchem. J."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1039\/D0AY02098B","article-title":"A review of pharmaceutical occurrence and pathways in the aquatic environment in the context of a changing climate and the COVID-19 pandemic","volume":"13","author":"Lawler","year":"2021","journal-title":"Anal. Methods"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"907","DOI":"10.1289\/ehp.99107s6907","article-title":"Pharmaceuticals and personal care products in the environment: Agents of subtle change?","volume":"107","author":"Daughton","year":"1999","journal-title":"Environ. Health Perspect."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1016\/j.ecoenv.2004.11.011","article-title":"Excretion and ecotoxicity of pharmaceutical and personal care products in the environment","volume":"63","author":"Jjemba","year":"2006","journal-title":"Ecotoxicol. Environ. Saf."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/j.watres.2014.08.053","article-title":"A review on emerging contaminants in wastewaters and the environment: Current knowledge, understudied areas and recommendations for future monitoring","volume":"72","author":"Petrie","year":"2015","journal-title":"Water Res."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"3933","DOI":"10.1007\/s00216-018-1015-9","article-title":"Recent trends in water analysis triggering future monitoring of organic micropollutants","volume":"410","author":"Schmidt","year":"2018","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_35","unstructured":"Helmenstine, A.-M. (2022, April 22). Spectroscopy Introduction. Thought Co. 26 August 2020. Available online: https:\/\/www.thoughtco.com\/introduction-to-spectroscopy-603741."},{"key":"ref_36","unstructured":"Sapkota, Anupama (2022, April 23). 22 Types of Spectroscopy with Definition, Principle, Steps, Uses. Available online: https:\/\/microbenotes.com\/types-of-spectroscopy\/."},{"key":"ref_37","unstructured":"Kierat, R.M. (2008). Synthese, Modifikation und Biologische Anwendung Fluoreszierender Xanthenfarbstoffe. [Inaugural Dissertation, Ruprechts-Karls-Universit\u00e4t Heidelberg]. Available online: http:\/\/www.ub.uni-heidelberg.de\/archiv\/8301."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Sauer, M., Hofkens, J., and Enderlein, J. (2011). Handbook of Fluorescence Spectroscopy and Imaging: From Single Molecules to Ensembles, Wiley.","DOI":"10.1002\/9783527633500"},{"key":"ref_39","unstructured":"Lakowicz, J.R. (2010). Principles of Fluorescence Spectroscopy, Springer."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"10530","DOI":"10.1021\/acs.chemrev.5b00321","article-title":"Nanoparticle Probes for the Detection of Cancer Biomarkers, Cells, and Tissues by Fluorescence","volume":"115","author":"Chinen","year":"2015","journal-title":"Chem. Rev."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"925","DOI":"10.1002\/ange.19730852102","article-title":"Chemische Anwendungen der Raman-Spektroskopie","volume":"85","author":"Schrader","year":"1973","journal-title":"Angew. Chem."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Vandenabeele, P. (2013). Practical Raman spectroscopy: An introduction. The Atrium Southern Gate Chichester West Sussex United Kingdom, Wiley.","DOI":"10.1002\/9781119961284"},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Post, C., Br\u00fclisauer, S., Waldschl\u00e4ger, K., Hug, W., Gr\u00fcneis, L., Heyden, N., Schmor, S., F\u00f6rderer, A., Reid, R., and Reid, M. (2021). Application of Laser-Induced, Deep UV Raman Spectroscopy and Artificial Intelligence in Real-Time Environmental Monitoring\u2014Solutions and First Results. Sensors, 21.","DOI":"10.3390\/s21113911"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"2258","DOI":"10.1021\/ac00276a065","article-title":"A new selective technique for characterization of polycyclic aromatic hydrocarbons in complex samples: UV resonance Raman spectroscopy of coal liquids","volume":"56","author":"Asher","year":"1984","journal-title":"Anal. Chem."},{"key":"ref_45","unstructured":"Liu, C. (2011). Implementation of Deep Ultraviolet Raman Spectroscopy. [Ph.D. Thesis, Technical University of Denmark]."},{"key":"ref_46","unstructured":"Photon Systems Inc. (2022, February 10). DUV Raman PL200. Fully Integrated, Lab Model Deep UV Resonance Raman & Photoluminescence Spectrometer, with Microscopic Imaging. Available online: https:\/\/photonsystems.com\/wp-content\/uploads\/2019\/02\/DUV-RamanPL200-Data-Sheet-V12-Web.pdf."},{"key":"ref_47","unstructured":"Photon Systems Inc. (2018, January 17\u201319). New Deep UV Raman & Photoluminescence Spectrometer System: The DUV Raman\/PL 200. Proceedings of the SPIE DCS 2018, Orlando, FL, USA."},{"key":"ref_48","unstructured":"Photon Systems Inc. (2022, February 10). Fused Fluorescence and Raman\u2014Photon Systems, 9.3.2020. Available online: https:\/\/photonsystems.com\/fused-fluorescence-and-Raman\/."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"863","DOI":"10.1016\/j.watres.2008.11.027","article-title":"Fluorescence as a potential monitoring tool for recycled water systems: A review","volume":"43","author":"Henderson","year":"2009","journal-title":"Water Res."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"2941","DOI":"10.1016\/j.watres.2007.04.012","article-title":"Freeze\/thaw and pH effects on freshwater dissolved organic matter fluorescence and absorbance properties from a number of UK locations","volume":"42","author":"Spencer","year":"2007","journal-title":"Water Res."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1016\/j.scitotenv.2015.05.114","article-title":"To what extent can portable fluorescence spectroscopy be used in the real-time assessment of microbial water quality?","volume":"532","author":"Baker","year":"2015","journal-title":"Sci. Total Environ."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"2214","DOI":"10.1016\/0043-1354(95)00046-N","article-title":"The effect of metal ions on the fluorescence of sewage wastewater","volume":"29","author":"Reynolds","year":"1995","journal-title":"Water Res."},{"key":"ref_53","unstructured":"(2022, April 04). BMUV Kurzinfo Abwasser\u2014Kl\u00e4ranlage. Available online: https:\/\/www.bmuv.de\/en\/topics\/water-resources-waste\/water-management\/wastewater\/sewage-treatment-plant."},{"key":"ref_54","first-page":"91","article-title":"Leistungssteigerung von Sandf\u00e4ngen","volume":"252","author":"Sonnenburg","year":"2020","journal-title":"Wien. Mitt."},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Zilch, K., Diederichs, C.J., Beckmann, K.J., Gertz, C., Malkwitz, A., and Moormann, C. (2020). Abwassertechnik. Handbuch f\u00fcr Bauingenieure, Springer Fachmedien.","DOI":"10.1007\/978-3-658-21749-5"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"6380","DOI":"10.1039\/c2ra20340e","article-title":"Chemical treatment technologies for waste-water recycling\u2014An overview","volume":"2","author":"Gupta","year":"2012","journal-title":"RSC Adv."},{"key":"ref_57","unstructured":"Franklin, L.B. (1991). Wastewater Engineering: Treatment. Disposal and Reuse, McGraw Hill, Inc."},{"key":"ref_58","doi-asserted-by":"crossref","unstructured":"Rosenwinkel, K., Kroiss, H., Dichtl, N., Seyfried, C., and Weiland, P. (2015). Anaerobtechnik, Springer.","DOI":"10.1007\/978-3-642-24895-5"},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/j.desal.2005.04.086","article-title":"Membrane bioreactor technology for wastewater treatment and reuse","volume":"187","author":"Melin","year":"2006","journal-title":"Desalination"},{"key":"ref_60","doi-asserted-by":"crossref","unstructured":"F\u00f6rstner, U., and K\u00f6ster, S. (2018). Umweltschutztechnik, Springer.","DOI":"10.1007\/978-3-662-55163-9"},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"149756","DOI":"10.1016\/j.scitotenv.2021.149756","article-title":"Improvement of wastewater and water quality via a full-scale ozonation plant?\u2014A comprehensive analysis of the endocrine potential using effect-based methods","volume":"803","author":"Wolf","year":"2022","journal-title":"Sci. Total Environ."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"1132","DOI":"10.1016\/j.trac.2007.10.002","article-title":"Advanced mass spectrometric methods applied to the study of fate and removal of pharmaceuticals in wastewater treatment","volume":"26","year":"2007","journal-title":"Trends Anal. Chem."},{"key":"ref_63","unstructured":"Fondermann, P. (2021). Investigation of Correlation of Selected Amino Acids to Sum Parameters in Monitoring of Wastewater Treatment Plants Using Fluorescence Laser Spectrometry. [Master\u2019s Thesis, Department of Engineering Geology and Hydrogeology, RWTH Aachen University]."},{"key":"ref_64","unstructured":"Pinnekamp, J. (2021, April 11). Grundlagen der Gew\u00e4sserg\u00fctewirtschaft und Siedlungswasserwirtschaft. Vorlesungsskript. RWTH Aachen, Lehrstuhl f\u00fcr Siedlungswasserwirtschaft und Wasserg\u00fctewirtschaft (ISA). not publicly accessible."},{"key":"ref_65","unstructured":"Penn, M.R., Pauer, J.J., and Mihelcic, J.R. (2021, April 09). Biochemical Oxygen Demand. Encyclopedia of Live Support Systems (EOLSS). Available online: http:\/\/www.eolss.net\/sample-chapters\/c06\/e6-13-04-03.pdf."},{"key":"ref_66","unstructured":"(2002). Water Quality\u2014Determination of the Chemical Oxygen Demand Index (ST-COD)\u2014Small-Scale Sealed-Tube Method (Standard No. ISO 15705:2002)."},{"key":"ref_67","unstructured":"(1989). Water Quality\u2014Determination of the Chemical Oxygen Demand (Standard No. ISO 6060:1989)."},{"key":"ref_68","unstructured":"(1975). Ausgabe 1975-02 Natriumchlorat f\u00fcr Industriezwecke; Bestimmung des Chloratgehaltes; Titrimetrische Dichromat-Methode (Standard No. ISO 3199)."},{"key":"ref_69","doi-asserted-by":"crossref","unstructured":"Reineke, W., and Schl\u00f6mann, M. (2020). Umweltmikrobiologie, Springer Spektrum. [3rd ed.].","DOI":"10.1007\/978-3-662-59655-5"},{"key":"ref_70","unstructured":"(2019). Water Analysis\u2014Guidelines for the Determination of Total Organic Carbon (TOC) and Dissolved Organic Carbon (DOC) (Standard No. DIN EN 1484)."},{"key":"ref_71","unstructured":"(2021). Environmental Solid Matrices\u2014Determination of Total Dissolved Solids (TDS) in Water and Eluates (Standard No. DIN EN 15216:2021-12)."},{"key":"ref_72","unstructured":"K\u00f6ppel, S., and Denner, M. (2021, November 29). DOC\/TOC im Eluat von Abf\u00e4llen aus der MBA. Evaluierung der Bestimmungsverfahren. Wien: Umweltbundesamt GmbH (Report\/Umweltbundesamt, [N.F.], p 298). Available online: https:\/\/www.umweltbundesamt.at\/fileadmin\/site\/publikationen\/REP0298.pdf."},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1016\/0039-9140(67)80001-8","article-title":"Process gas chromatography","volume":"14","author":"Pine","year":"1967","journal-title":"Talanta"},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"983A","DOI":"10.1021\/ac60361a778","article-title":"Process gas chromatography","volume":"47","author":"Villalobos","year":"1975","journal-title":"Anal. Chem."},{"key":"ref_75","doi-asserted-by":"crossref","unstructured":"Clemons, J. (2016). Chromatography in process analysis. Encyclopedia of Analytical Chemistry, Wiley.","DOI":"10.1002\/9780470027318.a2107.pub3"},{"key":"ref_76","doi-asserted-by":"crossref","unstructured":"Kessler, R.W. (2006). Prozessanalytik, Wiley.","DOI":"10.1002\/3527608990"},{"key":"ref_77","unstructured":"Straub, A. (2008). Einfache Messmethoden zur Charakterisierung sowie Ma\u00dfnahmen zur Erh\u00f6hung der Zuverl\u00e4ssigkeit und Leistungsf\u00e4higkeit biologischer Kleinkl\u00e4ranlagen. [Ph.D. Dissertation, Lehrstuhl Wassertechnik und Siedlungswasserbau der Brandenburgischen Technischen Universit\u00e4t Cottbus]."},{"key":"ref_78","unstructured":"EPA (1993). Method 180.1:1993\u2014Determination of Turbidity by Nephelometry, EPA."},{"key":"ref_79","unstructured":"(2016). Water Quality\u2014Determination of Turbidity\u2014Part 1: Quantitative Methods (Standard No. ISO 7027-1:2016(en)). Available online: https:\/\/www.iso.org\/standard\/62801.html."},{"key":"ref_80","doi-asserted-by":"crossref","unstructured":"Shi, Z., Chow, C.W.K., Fabris, R., Liu, J., and Jin, B. (2022). Applications of Online UV-Vis Spectrophotometer for Drinking Water Quality Monitoring and Process Control: A Review. Sensors, 22.","DOI":"10.3390\/s22082987"},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"6783","DOI":"10.1007\/s00216-019-02065-w","article-title":"Analytics 4.0: Online wastewater monitoring by GC and HPLC","volume":"411","author":"Wortberg","year":"2019","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_82","unstructured":"Photon Systems Inc. (2020). Manual: Raman PL 200, Photon Systems. unpublished."},{"key":"ref_83","doi-asserted-by":"crossref","unstructured":"Parthier, R. (2020). Messtechnik\u2014Vom SI-Einheitensystem \u00fcber Bewertung von Messergebnissen zu Anwendungen der Elektrischen Messtechnik, Springer. [9th ed.].","DOI":"10.1007\/978-3-658-27131-2"},{"key":"ref_84","unstructured":"(2022, April 05). KnowItAll-Software, Spektroskopie-Edition. Available online: https:\/\/sciencesolutions.wiley.com\/knowitall-software-spektroskopie-edition\/?lang=de."},{"key":"ref_85","unstructured":"G\u00f6rgens, M. (2021). Method Comparison of Laser Induced Fluorescence and Raman Spectroscopy Using Water Management Relevant Micropollutants. [Master\u2019s Thesis, Department of Engineering Geology and Hydrogeology, RWTH Aachen University]."},{"key":"ref_86","doi-asserted-by":"crossref","unstructured":"Wongburi, P., and Park, J.K. (2021). Big Data Analytics from a Wastewater Treatment Plant. Sustainability, 13.","DOI":"10.3390\/su132212383"},{"key":"ref_87","doi-asserted-by":"crossref","first-page":"4067","DOI":"10.1039\/C7AN01371J","article-title":"Deep convolutional networks for Raman spectrum recognition: A unified solution","volume":"142","author":"Liu","year":"2017","journal-title":"Analyst"},{"key":"ref_88","unstructured":"(2022, April 22). Directive (EU) 2020\/2184 of the European Parliament and of the Council of 16 December 2020 on the Quality of Water Intended for Human Consumption. Available online: https:\/\/eur-lex.europa.eu\/legal-content\/EN\/TXT\/PDF\/?uri=CELEX:32020L2184&from=ES."},{"key":"ref_89","doi-asserted-by":"crossref","unstructured":"Bhartia, R., Hug, W., and Reid, R. (2012). Improved sensing using simultaneous deep UV Raman and fluorescence detection. Chemical, Biological, Radiological, Nuclear, and Explosives (CBRNE) Sensing XIII (83581A), International Society for Optics Photonics.","DOI":"10.1117\/12.920170"},{"key":"ref_90","unstructured":"Reinartz, A. (2022). Investigation of Selected Disinfection Byproducts (DNP) in Ozonation of Wastewater Treatment Plants by Laser-Induced Raman and Fluorescence Spectroscopy\u2014Possibilities and Limitations of Application. [Master\u2019s Thesis, Department of Engineering Geology and Hydrogeology, RWTH Aachen University]."},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"1599","DOI":"10.1016\/0043-1354(94)00266-A","article-title":"Synchronous fluorescence spectroscopy of wastewater and some potential constituents","volume":"20","author":"Ahmad","year":"1995","journal-title":"Water Res."},{"key":"ref_92","doi-asserted-by":"crossref","first-page":"3069","DOI":"10.1080\/09593330.2013.803131","article-title":"Determination of changes in wastewater quality through a treatment works using fluorescence spectroscopy","volume":"34","author":"Bridgeman","year":"2013","journal-title":"Environ. Technol."},{"key":"ref_93","doi-asserted-by":"crossref","first-page":"134361","DOI":"10.1016\/j.scitotenv.2019.134361","article-title":"In situ fluorescence measurements of dissolved organic matter: A review","volume":"699","author":"Carstea","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_94","unstructured":"Sharpe, T.J. (2017). Assessing a Fluorescence Spectroscopy Method for In-Situ Microbial Drinking Water Quality. [Ph.D. Dissertation, Portland State University]."},{"key":"ref_95","doi-asserted-by":"crossref","first-page":"687","DOI":"10.1080\/09593330.2011.588401","article-title":"Fluorescence spectroscopy as a tool for determining microbial quality in potable water applications","volume":"33","author":"Cumberland","year":"2012","journal-title":"Environ. Technol."},{"key":"ref_96","unstructured":"Mohrdieck, M. (2021). Optimierung von Wasseraufbereitungsprozessen \u00fcber ein Echtzeit-Monitoring von Summenparametern mit Hilfe der Fluoreszenz-Laserspektroskopie. [Master\u2019s Thesis, Department of Engineering Geology and Hydrogeology, RWTH Aachen University]."},{"key":"ref_97","doi-asserted-by":"crossref","first-page":"619","DOI":"10.1039\/C4EM00473F","article-title":"Exploring the relationship between the optical properties of water and the quality and quantity of dissolved organic carbon in aquatic ecosystems: Strong correlations do not always mean strong predictive power","volume":"17","author":"Baldwin","year":"2015","journal-title":"Environ. Sci. Process. Impacts"},{"key":"ref_98","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.marchem.2009.10.002","article-title":"Characterization of dissolved organic matter fluorescence in the South Atlantic Bight with use of PARAFAC model: Relationships between fluorescence and its components, absorption coefficients and organic carbon concentrations","volume":"118","author":"Kowalczuk","year":"2010","journal-title":"Mar. Chem."},{"key":"ref_99","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1016\/j.watres.2014.01.053","article-title":"Spectroscopic characterization of dissolved organic matter changes in drinking water treatment: From PARAFAC analysis to online monitoring wavelengths","volume":"54","author":"Shutova","year":"2014","journal-title":"Water Res."},{"key":"ref_100","unstructured":"Schmor, S. (2020). Development of Raman Measurement Standards for Selected Substances in Sewage\u2014Conception and Execution of a Flow Experiment. [Master\u2019s Thesis, Department of Engineering Geology and Hydrogeology, RWTH Aachen University]."},{"key":"ref_101","doi-asserted-by":"crossref","first-page":"578","DOI":"10.1143\/JPSJ.35.578","article-title":"Raman Spectra of Irradiated Alkali Bromate Crystals","volume":"2","author":"Radhakrishna","year":"1973","journal-title":"J. Phys. Soc. Jpn."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/13\/4668\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:36:26Z","timestamp":1760139386000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/13\/4668"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,6,21]]},"references-count":101,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2022,7]]}},"alternative-id":["s22134668"],"URL":"https:\/\/doi.org\/10.3390\/s22134668","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,6,21]]}}}