Thomas Ertl

BOKU University | boku · Institute of Sanitary Engineering and Water Pollution Control

Most of the world’s rivers are shaped by interacting social and natural processes. As Industrialised Riverine Landscapes (IRLs), they have become part of our critical infrastructure, vital for the water-energy-food nexus, but also subject to extreme events and vulnerable to biodiversity loss in the wake of global change. This situation poses major...

The advancing digitalisation is one of the great challenges of our times. Related activities also concern the wastewater sector. In the field of building construction, one emerging approach is building information modelling (BIM). The presented work investigates to which extent BIM practices have already found their way to wastewater management, an...

Zusammenfassung Natur-basierte Systeme (NBS) sind Schlüsseltechnologien in der Siedlungswasserwirtschaft für die urbane Wasserwirtschaft sowie die Abwasserreinigung. Die Entwicklung von NBS begann in den 1960er-Jahren mit bepflanzten Bodenfiltern (auch Pflanzenkläranlage genannt) und führte zur Entwicklung und Anwendung diverser NBS für die Wassera...

Green roofs (GRs) and vertical greenery systems (VGSs) can contribute certain pollutants to stormwater runoff, affecting the quality of the receiving waters. The objective of this review paper is to discuss the potential impact of these systems on the quality of urban runoff. In the green building systems section, a series of materials used in gree...

River systems have undergone a massive transformation since the Anthropocene. The natural properties of river systems have been drastically altered and reshaped, limiting the use of management frameworks, their scientific knowledge base and their ability to provide adequate solutions for current problems and those of the future, such as climate cha...

In many countries around the world heating (and cooling) has been and will remain the biggest energy sector, but it is still widely dominated by fossil energy sources today. Wastewater as a source of renewable energy contains large amounts of heat and due to its place-bound localization in urban sewer systems it is usually also situated in very clo...

Cities worldwide are facing several challenges connected to urbanization and climate change. Several cities have identified the implementation of nature-based solutions (NBS) as an option to mitigate several challenges at once. However, can two different aims be reached with NBS in the same location? This question has not yet been addressed. This p...

The application of blue and green infrastructure in urban stormwater management has attracted increasing interest in recent years. At the same time, one can observe a heavy modification of urban watercourses by land reclamation measures aiming at canalizing, straightening, and draining existing water systems at many places around the world. In the...

Multiple pressures as urbanization, densification and climate change lead to the need for adaptation of sewer systems within urban environments. To increase the adaptive capacity of stormwater management systems, there is a shift towards decentralized nature-based solutions (NBS). Especially in densely built areas the availability of land can be a...

In December 2018, wastewater was officially recognized by the European Union as a renewable source of energy, thus wastewater heat recovery can be included in efforts to reduce greenhouse gas emissions. Given the fact that wastewater treatment plants can generate enormous heat surpluses, this decision gives leeway to couple the wastewater infrastru...

The formation of dew is a highly complex occurrence, as many factors have an influence on it. Short term investigation may give data about water output, but reliability with respect to certain key factors require long term monitoring. The main results are currently being quantified.

The formation of dew is a highly complex occurrence, as many factors have an influence on it. Short term investigation may give data about water output, but reliability with respect to certain key factors require long term monitoring. The main results are currently being quantified.

Pluvial flood risk is increasing in urban and rural areas due to changes in precipitation patterns and urbanization. Pluvial flooding is often associated with insufficient capacities of the sewer system or low surface drainage efficiency of urban areas. In hilly areas, hillside runoff additionally affects the risk of pluvial flooding. This article...

Environmental modeling studies aim to infer the impacts on environmental variables that are caused by natural and human-induced changes in environmental systems. Changes in environmental systems are typically implemented as discrete scenarios in environmental models to simulate environmental variables under changing conditions. The scenario develop...

Pluvial flood risk is increasing in urban and rural areas due to changes in precipitation patterns and urbanization. Pluvial flooding is often associated with insufficient capacities of the sewer system or low drainage efficiency of urban areas. In hilly areas hillside runoff additionally affects the risk of pluvial flooding. In the presented case...

It is widely accepted that partial nitrification by ANAMMOX has the potential to become one of the key processes in wastewater treatment. However, large greenhouse gas emissions have been panobserved in many cases. A novel mesh separated reactor, developed to allow continuous operation of deammonification at smaller scale without external biomass s...

Climate change is one of the great challenges of our times. In the search for renewable energy sources, wastewater has received increasing attention in recent years. This is due to the fact that it can serve as a source of electricity and heat supply, as well as a substitute for natural gas. The current literature frequently addresses more technica...

Utilization of filtration systems plays a significant role in removing contaminants from storm water runoff. In this study, pilot-scale experiments are conducted to investigate heavy metal removal capacity for ten substrate mixtures. Tested filter substrates contained 10−15 vol.-% compost. The experiments are conducted using synthetic storm water a...

In der Bewirtschaftung von Niederschlagswasser setzt sich in den letzten Jahren ein Trend in Richtung dezentraler, flexibler Lösungen und grüner Infrastruktur durch, um besser an künftige Herausforderungen wie den Klimawandel oder die Urbanisierung angepasst zu sein. Bei der Erweiterung oder Neuerschließungen von Siedlungsgebieten wird zunehmend de...

Um den Auswirkungen des Klimawandels in urbanen Gebieten wie Starkniederschläge und Bildung von Hitzeinseln entgegenzuwirken, sind für die Siedlungswasserwirtschaft neue Konzepte nötig. Dabei spielt der Begriff „Grüne Infrastruktur (GI)“ eine ganz zentrale Rolle. Dachbegrünung, grüne Fassade und bepflanzte Filtersysteme – sogenannte Retentionsfilte...

Die österreichische Klärschlammverwertung befindet sich im Umbruch. 2030 sollen bis zu 85 % des kommunalen Klärschlammanfalls einer Monoverbrennung zugeführt werden, um aus der dabei anfallenden Asche Phosphor rückzugewinnen. Die im Land verfügbaren Kapazitäten reichen aktuell noch bei Weitem nicht aus, um das genannte Ziel erfüllen zu können. Die...

Environmental modeling studies aim to infer the impacts on environmental variables that are caused by natural and human-induced changes in environmental systems. Changes in environmental systems are typically implemented as discrete scenarios in environmental models to simulate environmental variables under changing conditions. The scenario develop...

Integrative models, such as the Soil and Water Assessment Tool (SWAT; Arnold et al., 1998), are useful to assess the impacts of system changes (e.g. climate change or land use change) on water balance components, nutrient loads and other environmentally relevant variables. To draw well informed conclusions from the model outputs, a profound knowled...

Determination of parameters describing the hydraulic behavior of filter materials for stormwater filters using HYDRUS

From a scientific point of view, it is unquestioned that numerical models for technical systems need to be calibrated. However, in sufficiently calibrated models are still used in engineering practice. Case studies in the scientific literature that deal with urban water management are mostly large cities, while little attention is paid to the diffe...

The main purpose of wastewater treatment plants concerns water pollution control. However, recent research has shown, that wastewater treatment plants also seem to be interesting from an energetic point of view, as they have high potentials for heat generation beyond common digester gas combustion. Focusing on a case study we intend to feed the ava...

Wastewater contains significant quantities of thermal energy. Consequently, heat recovery in sewer systems can provide urban areas with an additional source of renewable energy for heating of buildings. However, certain treatment processes in a wastewater treatment plant are temperature-sensitive. From a water protection perspective it is therefore...

Im Hinblick auf den Einfluss von Klimawandel auf die Ressource Wasser können in naher Zukunft Maßnahmen zum Erhalt der Ressource und deren Qualität notwendig sein. Um fundierte Aussagen über einen Klimawandeleinfluss und eventuelle Adaptierungsmaßnahmen treffen zu können, ist eine Kenntnis der Unsicherheiten relevanter Prognosen von Bedeutung. Im R...

Although the main function of a wastewater treatment plant (WWTP) is to remove various constituents from wastewater it can also serve as a source of energy and other materials. The generated resources can be used either on-site at the WWTP or elsewhere at an adjacent infrastructure. In the course of a current national research project, the possibil...

Wastewater heat recovery via heat exchangers and heat pumps constitutes an environmentally friendly, approved and economically competitive, but often underestimated technology. By introducing the spatial dimension in feasibility studies, the results of calculations change considerably. This paper presents a methodology to estimate thermal energy re...

Operation and maintenance of the public sewer system represent key tasks for an operator. Condition assessment is usually conducted by conventional closed circuit television (CCTV) inspection. However, alternative tools such as manhole-zoom cameras (MZCs) and the acoustic technology SewerBatt® are available today. The INNOKANIS project investigates...

Maintaining public sewer systems is one of sewer operators’ key responsibilities. Thus, information regarding the condition of the sewer system based on regular inspections is crucial in order to ensure operability and identify areas in need of rehabilitation. Condition assessments are usually carried out either directly by operational staff or ind...

Waste water treatment plants not only treat waste water, they can also act as a source of energy. The produced energy is either used to fulfil in-house energy requirements or fed into public energy distribution grids. Research in Austria and other countries has shown that waste water treatment has high energy potential which is yet unexploited. The...

Im Rahmen des Projektes SCHTURM (Schadstoffemissionen urbaner Siedlungsgebiete aus Kläranlagen, Regen- und Mischwasserentlastungen) wurden unterschiedliche Eintragspfade in Gewässer auf organische und anorganische Spurenstoffe untersucht. Das Ziel ist eine frachtbasierte Bewertung der Emissionen aus einem Siedlungsgebiet und die Identifikation von...

The current version of the Austrian Water Rights Act states that target conditions of surface waters and groundwater have to be defined. Regulations have been worked out, which include the definition of characteristic conditions of water bodies as well as threshold and guiding values. Today, many data regarding the effluent of wastewater treatment...

Using constructed wetlands (CWs) with vertical flow and intermittent loading, high organic matter and ammonium removal can be achieved. In the case of additional requirements for phosphorus removal, which in Austria often occurs if the treated wastewater is discharged into small sensitive receiving waters, additional measures have to be taken. The...

Die optische Inspektion von Entwässerungssystemen und die damit verbundene Zustandserfassung nach ÖNORM EN 13508-2/A1 (ÖNORM EN 13508-2/A1 (2010): Zustand von Entwässerungssysteme außerhalb von Gebäuden – Teil 2: Kodiersystem für die optische Inspektion.) sind heute wichtige Aspekte des integralen Kanalmanagements nach ÖNORM EN 752 (ÖNORM EN 752 (2...

In Österreich werden heute rund 100.000 km öffentliche Kanalisation betrieben, wobei die Kanalreinigung zu einer der Kernaufgaben eines Kanalisationsunternehmens zählt. Aufgrund der prekären finanziellen Situation vieler Städte und Gemeinden stellt die Kanalreinigung jedoch eine erhebliche finanzielle Belastung dar. Die Folge davon ist, dass viele...

In the UK, the majority of sewer pipe inspections are carried out using closed-circuit television (CCTV) technology. This inspection technology is expensive; given the size of the UK sewer network, this means that only a small sample of network is inspected regularly. Up-to-date condition information on individual sewers is required to minimise sew...

In Austria the global financial crisis of the last decade led to major financial problems in the municipalities. The more the municipalities face such difficulties the more it is essential to provide infrastructure operation and maintenance prioritization methods which focus on risks to the public and the environment. A risk assessment methodology,...

In Austria, a cooperative research project including partners of five utilities and three research institutes is in progress dealing with strategic sewer rehabilitation planning. One of the objectives of the research is to define measurable performance indicators (PIs) related to service levels, which can be used at a national, but also at an inter...

In common with most infrastructure systems, sewers are often inspected visually. Currently, the results from these inspections inform decisions for significant investments regarding sewer rehabilitation or replacement. In practice, the quality of the data and its analysis are not questioned although psychological research indicates that, as a conse...

International research isalready dealing with different aspects of sewer rehabilitation planning. Today several strategies, techniques and tools are available. But due to their complexitymany of the available approaches are not applied in practice. In Austria no standardised approach regarding sewer rehabilitation planning is currently available. T...

Summary The house connection as the interface between house sewer and main pipe as well as the house sewer itself have substantial technical, organisational, economic and environmental effects on sewerage management in a drainage district. The total length of house sewers in Austria is not known exactly, but is estimated at about twice the length...

Summary The cost of short and medium term sewer rehabilitation requirements in Bavaria has been put at 4 to 5 billion euros. The fact that sewerage systems in Austria are comparable in structure suggests that the costs and requirements for these measures will be on a similar scale. As a means of studying the state of repair of sewers, TV inspection...

Mountain refuges comprise systems for energy and water supply, wastewater and waste disposal operating under unfavourable conditions. To identify optimization potential an integrated evaluation of existing systems and experiences is carried out on international basis (data base: 100 mountain refuges). Therefore, an adapted performance indicator app...

In February 2002 an Austrian benchmarking project was completed. The present paper reports on the part of the project dealing with benchmarking of sewerage systems, with a focus on the analysis of investment costs of 34 sewerage system projects. The paper explains the methodology used to make the investment costs of the projects comparable. This wa...

Regarding the average age of sewers in Austria, rehabilitation becomes more and more important. In Austria so far no guideline for sewer maintenance and rehabilitation strategies exists. The paper reports about the preparation for developing a guideline to raise the working quality of several branches involved in sewer maintenance like e. g. high p...

Das erste Jahr des ÖWAV-Abwasserbenchmarkings konnte mit Hilfe der Benchmark-Internetplattform im Dezember 2005 mit der Erstellung des Endberichtes erfolgreich abgeschlossen werden. Insgesamt haben 30 Abwasseranlagen am Benchmarkvergleich im Jahr 2005 (Auswertungsjahr 2004) teilgenommen. 24 Betreiber beteiligten sich am Kläranlagen-Benchmarking, se...

1 s::can Messtechnik GmbH, Herminengasse 10, A-1020 Vienna, Austria. ABSTRACT The paper describes on-line and in-situ measurements of the nitrate nitrogen concentration in a sewer. The measurements were carried out to enable automated control of iron nitrate dosing to prevent odour problems. A submersible UV/VIS spectrometer (spectro::lyser by s::c...

In 2000, a multidisciplinary research project was launched with the aim of developing a benchmarking method for enterprises responsible for the operation of sewer systems and waste water treatment plants. This project was carried out for, and financed by, the Austrian Ministry of Agriculture, Forestry, the Environment and Water Management, 8 of the...

Non-ionic surfactants are widely used for household and industrial purposes. For different reasons the metabolites, e.g. 4-nonylphenol, nonylphenol monoethoxylate, nonylphenol diethoxylate and 4-tert-octylphenol, are especially considered to be endocrine disruptive and thus potentially harmful for the environment. In this study, field samples of ra...

Organotin compounds are suspected to have endocrinous effects even in quantities corresponding to the ng/l range. A study has been carried out measuring tributyl tin compounds in the sewage of various industrial plants. The results have shown that the largest concentrations come from a chemical firm and a laundry and that the households, too, contr...

The appearance of infiltration water in sewers can lead to significant operational problems in sewers as well as in wastewater treatment plants. Today many different approaches to estimate and determine the share of infiltration water in sewer systems are known. In general one can distinguish between quantitative and qualitative approaches. The for...