This study investigates the performance of a newly developed flow-through reactor and the utilized photocatalytic materials in two environments: a lab-scale experiment and a pilot-scale experiment in a contaminated building. The aim was to assess the removal of polycyclic aromatic hydrocarbons from the air using an innovative reactor equipped with an ultraviolet-irradiated titanium dioxide catalyst. Empirical measurements were conducted in the laboratory to revise the developed fixated titanium dioxide catalysts at different irradiances. Naphthalene and 1-methylnaphthalene elimination were used as model substances due to being the most volatile polycyclic aromatic hydrocarbons (PAH). In addition, they are often found in contaminated buildings. Tests in an office building revealed high suitability of the air cleaning system for low polycyclic aromatic hydrocarbons concentrations with a degradation of the compounds below the allowed limits of indoor air pollutants set by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. The degradation of the organic micropollutants proceeded without detection of by-products, so that mineralization can be assumed. Based on these observations and a large number of previous studies, detailed degradation pathways for the selected micropollutants were also established.

Der Klimawandel ist in den vergangenen Jahren auch in Europa immer sichtbarer geworden. Die deutlichsten Auswirkungen zeigen sich für die Wasserwirtschaft in den beiden extremen Formen Starkregen und Trockenheit. Die Trockenperioden in den Jahren 2018 und 2019 sowie die schweren Überschwemmungsereignisse in 2021 an der Ahr, der Erft und anderswo haben auf Seiten der Fachwelt die Sensibilität für die Auswirkungen dieser Wetterextreme weiter gesteigert. Mehr und mehr werden Lösungen zur Vorbeugung und Anpassung an die erwartete Zunahme solcher Ereignisse entwickelt. Viele deutsche Bundesländer stellen beispielsweise für die Erstellung von Starkregengefahrenkarten umfangreiche Fördermittel zur Verfügung. Die erforderlichen Bemühungen beschränken sich aber nicht nur auf erforderliche Maßnahmen bei Extremwetterereignissen. Zunehmend müssen (ab-)wasserwirtschaftliche Einrichtungen effizienter gestaltet werden, da sie nach wie vor einen erheblichen Energieverbraucher insbesondere in kleinen und mittelgroßen Gemeinden darstellen. Hier leistet die Wasserwirtschaft seit vielen Jahren einen wichtigen Beitrag zur Reduzierung von CO2 durch stetig zunehmende Effizienzsteigerungen in technischen Einrichtungen. Dabei nimmt die Digitalisierung wie in anderen Wirtschafts- und Gesellschaftssektoren eine besondere Stellung bei der Entwicklung passender und wirksamer Lösungen ein. Forscher der Hochschule Hof haben im Rahmen des Vorhabens „WaterExe4.0“ (gefördert vom Bundesministerium für Bildung und Forschung) eine erste Metastudie zur Digitalisierung in der deutschsprachigen Wasserwirtschaft erstellt. In dieser Studie stellte sich heraus, dass trotz erheblicher Entwicklungsschübe in den letzten Jahren und Zunahme der Lösungsangebote auf den ersten Blick noch eine große Lücke zwischen Angebot und Umsetzung besteht. Ein realer Anwendungsbezug konnte nur für 11 % der rund 700 identifizierten Produkte, Projekte und Studien identifiziert werden. Um die Gründe für dieses scheinbare Ungleichgewicht herauszufinden, erfolgte die ergänzende Befragung von Expert:innen der Wasserwirtschaft. Die Antworten zeigten diesbezüglich beispielsweise auf, dass alltägliche Probleme zu wenig oder kaum in neuen Lösungen berücksichtigt werden, was die Anwender:innen stark überfordert. Weiterhin wird der Mehrwert einer Digitalisierungslösung für die jeweilige individuelle Situation noch immer zu wenig sichtbar. Zudem fehlen systematische Analysetools, um wesentliche Hindernisse infolge neuer Ideen zu identifizieren und den besten Weg für den Start und die Umsetzung eines Digitalisierungsprojekts zu finden. Die Komplexität des Themas führte dazu, dass die Studie „WaterExe4.0“ mithilfe von vier methodisch unterschiedlichen Teilerhebungen (Literatur- und Marktrecherche, Befragung, Expert:inneninterview und Workshops) durchgeführt wurde. Die Ergebnisse geben damit einen umfangreichen Überblick über die aktuelle Situation in der deutschsprachigen Wasserwirtschaft und zeigen die Erwartungen der Branchenteilnehmer für die Zukunft auf.

Supported titanium dioxide-based photocatalysts were investigated for the degradation of pharmaceuticals under irradiation with UV−A LEDs. Focus of the presented research was placed on the degradation kinetics under different matrix influences and energy flux densities of UV−A radiation. The chemical parameters, pH, orthophosphate, nitrogen concentration and background organic concentration were investigated. The results were evaluated by time-resolved measurement of the concentrations and by calculating and plotting the first-order degradation rate. The results showed clear differences in the rates of degradation of each compound, with diclofenac being the most easily degraded and metoprolol the most resistant. When the influence of energy flux density was examined, a linear relationship between degradation rate and the square root of energy flux density was confirmed. The organic background matrix has a strong influence on the degradation kinetics of the compounds. Nitrogen and orthophosphate slow down the degradation much less than the organic background matrix. Investigating the pH influence, it could be shown that almost no degradation is detected in the basic pH range. The results were illustrated with the help of a radar diagram, which can show all dependencies at a glance.

In the present work, a suitable experimental setup was developed to successfully apply advanced oxidation processes (AOP) to real groundwater matrices. This setup combines an O3-bubble column reactor with a carrier-bound TiO2/UV-system. The degradation of various chlorinated ethene and methane derivatives commonly found of chlorinated volatile organic compound polluted regional groundwater samples was investigated. Because of known issues within water remediation using AOP such as toxification by transformation products, this study aimed at complete mineralization of the contained organic micropollutants. Moreover, the influences of variable process parameters such as flow rate, ozone concentration, and radiation dose on process performance were statistically evaluated and discussed. Parameter optimization using a Box-Behnken experimental design resulted in very promising degradation rates. It was thus possible to achieve a degradation rate of at least 98% for cis-dichloroethene, trichloroethene and tetrachloroethene and 85% for trichloromethane without formation of transformation products. The results of this work open up the possibility of developing innovative technologies based on AOP, which can be universally applied even to challenging matrices such as groundwater.

Immobilized titanium dioxide catalysts were used within a photocatalytic immersion rotary body reactor, which was connected to a substream ozonation unit to remove micro-pollutants from wastewater. Within this work data on the behavior of cumulative parameters during treatment of wastewater by photocatalysis and photocatalytic ozonation are provided. The investigated parameters are spectral absorption coefficient at 254 nm (SAC254), total organic carbon (TOC) and chemical oxygen demand (COD). All experiments were carried out using secondary effluent from the same wastewater treatment plant. For the parameter SAC254, consistent concentration curves and dependencies to operational parameters of the experimental system could be measured. The measurements of the parameters TOC and COD showed greater uncertainties, although basic trends could nonetheless be observed. A good linear correlation (R2 < 0.85) between the reduction of SAC254 and 8 micro-pollutants for photocatalysis and photocatalytic ozonation was found. This confirms the suitability of the SAC254 as a control parameter for a large-scale application of a photocatalytic 4th treatment stage. A linear correlation between measured TOC and COD degradation rates was possible with a coefficient of determination of 0.58–0.86. The simultaneous decrease of TOC and COD is an indicator for a mineralization of the treated wastewater matrix.

Als vor drei Jahren die Idee zur Technologieinitiative KOMMUNAL 4.0 entstand, der nun zur Plattforum Kommunal 4.0 e. V. geführt hat, war das Thema Digitalisierung in der Wasserwirtschaft nur vereinzelt präsent. Ausgehend von dem Gedanken, die Grundidee von Industrie 4.0 auf die kommunale Wasserwirtschaft zu übertragen, stellten die Initiatoren von KOMMUNAL 4.0 fest, dass schon seit Jahren unzählige Daten in zahlreichen wasserwirtschaftlichen Anlagen und Objekten erfasst und archiviert wurden. Zumeist beschränkte sich die Datennutzung auf die aktuelle Prozessbeobachtung oder die Nachweisführung der Regel- und Gesetzeskonformität gegenüber den zuständigen Behörden.

Überall in Wirtschaft und Gesellschaft wird von Digitalisierung und dem Internet der Dinge gesprochen, zunehmend auch in der kommunalen Wasserwirtschaft. Impulsgeber ist die Digitalisierungsoffensive der Industrie, zusammengefasst unter dem Begriff Industrie 4.0. Diese basiert auf intelligenten, digital vernetzten Systemen, die eine sich selbst organisierte Produk­tion ermöglichen sollen.

Carrier-bound titanium dioxide catalysts were used for the photocatalytic conversion of nitrogen dioxide. In this context, inexpensive metal oxide sensors were tested for their usefulness in the investigation and characterization of the photocatalysts. UV-A light emitting diodes of wavelength 365 nm stimulated the catalysts. By dimming the light emitting diodes, the influence of the energy flux density on the conversion kinetics could be investigated. The observed conversation followed first-order kinetics. The light intensity has shown a large influence at lower irradiances. At high irradiances an increase in recombination effects can be assumed, which makes irradiances greater than 40 W/m2 inefficient. From that point on no significant increase in the rate of conversation could be measured. The photon efficiency at low irradiances was determined to be 4.55% decreasing to 0.59% at higher irradiances. The flow rate of gas passing through the catalysts appears to have a linear effect on the overall rate of conversion. This is evidenced by a constant half-life within the reactor in relation to variable flow rate. The sensors have been shown to be calibratable and sufficiently stable, which raises the possibility of using the sensors for spatially resolved measurements within reaction systems.

Persistent and mobile (PM) substances are being recognized as serious threats to water resources and drinking water suppliers have to use advanced treatment if raw waters are contaminated with such compounds. In this study, analytical methods for 25 micropollutants for which insufficient or no data on their occurrence in surface waters and on their behavior during drinking water treatment were available, were developed. More than 120 surface water samples were analyzed and laboratory tests were performed to evaluate the compounds' behavior during aerobic bank filtration (BF), activated carbon treatment, and ozonation. Ensulizole, 1,3-diphenylguanidine and 2-acrylamido-2-methylpropane sulfonic acid revealed the highest detection frequencies in the Rhine river. Concentration level and detection frequency correlated positively with the wastewater fraction. However, street run-off is likely an additional discharge pathway for 1,3-diphenylguanidine. In simulated BF, seven (six) substances could be classified as persistent (very persistent). By applying powdered activated carbon, 42% of the substances were well removed as was the case for 50% of the compounds when applying 0.2 mg/L O3. In total, eight of the substances detected in surface waters were weakly removed by at least one of the investigated removal processes and may cause problems for drinking water suppliers.

Industrie 4.0 hält seit rund zehn Jahren Einzug in die deutsche Wirtschaft. Auch die deutsche Wasserwirtschaft ist in Sachen Di- gitalisierung auf dem Weg in die digitale Transformation. Seit 2015 hat die Zahl der Forschungs- und Entwicklungsprojekte zur Digitalisierung der deutschen Wasserwirtschaft stark zuge- nommen. Allerdings folgen insbesondere kleine und mittlere Kommunen diesem Trend nicht konsequent genug. Um mehr Klarheit zum Stand der Digitalisierung in der Wasserwirtschaft und zur Frage der Umsetzung im kommunalen Bereich zu erhal- ten, schuf das iwe Institut für Wasser- und Energiemanagement der Hochschule Hof mit der Metastudie WaterExe 4.0 die Daten- basis für einen ab 2022 erscheinenden jährlichen Digitalisie- rungsreport der Wasserwirtschaft. Ziel der Studie war es, erst- mals einen belastbaren Überblick über bisherige Forschungspro- jekte und technologische Entwicklungen in Deutschland, Öster- reich und der Schweiz zur Digitalisierung in der Wasserwirtschaft zu erhalten.

Carrier-bound titanium dioxide catalysts were used in a photocatalytic ozonation reactor for the degradation of micro-pollutants in real wastewater. A photocatalytic immersion rotary body reactor with a 36-cm disk diameter was used, and was irradiated using UV-A light-emitting diodes. The rotating disks were covered with catalysts based on stainless steel grids coated with titanium dioxide. The dosing of ozone was carried out through the liquid phase via an external enrichment and a supply system transverse to the flow direction. The influence of irradiation power and ozone dose on the degradation rate for photocatalytic ozonation was investigated. In addition, the performance of the individual processes photocatalysis and ozonation were studied. The degradation kinetics of the parent compounds were determined using liquid chromatography tandem mass spectrometry. First-order kinetics were determined for photocatalysis and photocatalytic ozonation. A maximum reaction rate of the reactor was determined, which could be achieved by both photocatalysis and photocatalytic ozonation. At a dosage of 0.4 mg /mg DOC, the maximum reaction rate could be achieved using 75% of the irradiation power used for sole photocatalysis, allowing increases in the energetic efficiency of photocatalytic wastewater treatment processes. The process of photocatalytic ozonation is suitable to remove a wide spectrum of micro-pollutants from wastewater.

Many municipalities and cities are facing numerous, sometimes very complex water management challenges. In addition to heavy rainfall events, because of climate change, this also applies to the necessary improvement of water quality about trace substances and micro plastics. This also means an increase in the complexity of tasks, a diversity of levels of action and knowledge. The necessary freedom to acquire new knowledge in an appropriate manner in terms of content and time is becoming increasingly limited because of these framework conditions. An additional burden is the fact that it is becoming more and more difficult to obtain adequate specialized staff. Therefore, the necessary planning processes are becoming longer. The implementation of environmental protection measures has to follow later. Furthermore, new, and more efficient methods for better environmental protection are used less frequently or only insufficiently because there is too little knowledge about them. Experts promise more support and facilitation by solutions that have been developed during digitalization and offered on the market for technical and organizational level [1]. Here, however, there is often a lack of time on the user’s side to act in an appropriate manner with resource- supporting IT systems that make it possible to automate or simplify standard procedures or make processes more efficient and effective. If external consultants are part of the selection of appropriate IT systems, successful implementation and use often fails due to the lack of fit between the IT system and the existing organizational structure or culture, as well as in relation to the human end user. Two ways to address these obstacles are the “Anyway Strategy” and “ HELIP” methods. They are the result of a meta-study on success factors and barriers in the selection and application of digitalization solutions [1] and a from a development project for digital innovations [2] in the water industry.

Das iwe-Institut für Wasser- und Energiemanagement an der Hochschule Hof hat eine Metastudie zum Stand der Digitalisierung der Wasserwirtschaft in den deutschsprachigen Ländern durchgeführt. Das Fazit: Die Digitalisierung ist zu einem festen Bestandteil technologischer Lösungen und strategischer Entscheidungen geworden. In einer dreiteiligen Serie berichtet die WasserWirtschaft über die Ergebnisse der Studie. Im dritten Teil der Serie geht es um die Frage, welche Konsequenzen aus den Erkenntnissen und Ergebnissen der Studie zu ziehen sind und wie die Zukunft der Digitalisierung in der Wasserwirtschaft aussehen kann.