Author
Hanns Plihal
Bio: Hanns Plihal is an academic researcher from University of Natural Resources and Life Sciences, Vienna. The author has contributed to research in topics: Sanitary sewer & Wastewater. The author has an hindex of 4, co-authored 10 publications receiving 134 citations.
Topics: Sanitary sewer, Wastewater, Filtration, Risk assessment, Nitrification
Papers
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TL;DR: In this article, the authors assess the quality of the analysis of visual sewer inspection data by analysing data reproducibility; three types of capabilities to subjectively assess data are distinguished: the recognition of defects, the description of defects according to a prescribed coding system and the interpretation of sewer inspection reports.
Abstract: 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 consequence of the use of subjective analysis of the collected images, errors are inevitable. This article assesses the quality of the analysis of visual sewer inspection data by analysing data reproducibility; three types of capabilities to subjectively assess data are distinguished: the recognition of defects, the description of defects according to a prescribed coding system and the interpretation of sewer inspection reports. The introduced uncertainty is studied using three types of data: inspector examination results of sewer inspection courses, data gathered in day-to-day practice, and the results of repetitive interpretation of the inspection results. After a thorough analysis of the data it can be concluded that for all cases visual sewer inspection data proved poorly reproducible. For the recognition of defects, it was found that the probability of a false positive is in the order of a few percent, the probability of a false negative is in the order of 25%.
120 citations
TL;DR: In this paper, the INNOKANIS project investigates structural and operational condition assessment in the sewer system by means of three MZC models and SewerBatt® to develop a combined optical and acoustic device as a cost-effective alternative to conventional CCTV inspection.
Abstract: 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 structural and operational condition assessment in the sewer system by means of three MZC models and SewerBatt® to develop a combined optical and acoustic device as a cost-effective alternative to conventional CCTV inspection. The first field trials of the ongoing project were conducted in Austria in 2011. 640 conditions according to EN 13508-2/A1 were investigated and compared against conventional CCTV reports. Individual and combined detection rates for both devices were calculated. Based on the current findings, both MZC and SewerBatt® are effective alternatives to conventional CCTV inspection. In addition, performance is significantly enhanced when ...
16 citations
TL;DR: In this paper, the authors investigated the operational condition assessment of sewers by means of different manhole-zoom cameras and found that only 1% of the pipe sections of combined sewers and 11% of sanitary sewers require additional cleaning.
Abstract: Currently, around 100,000 km of public sewers are operated in Austria, with cleaning as one of the main tasks for a wastewater utility. Due to the precarious financial situation of many cities and municipalities sewer cleaning represents a considerable financial burden, resulting in the extension of cleaning intervals and the delay of required cleaning activities. Different approaches to sewer management can be distinguished. If a selective strategy is adopted, only pipe sections with deposits are cleaned. Thus, detailed information regarding the amount of deposits is required. A simple and quick method to inspect the sewer system and assess the degree of sediments is by means of a manhole-zoom camera. The current research project INNOKANIS investigates the operational condition assessment of sewers by means of different manhole-zoom cameras. So far the data suggest that the majority of investigated pipe sections belongs to the self-cleaning category. Only 1% of the pipe sections of combined sewers and 11% of sanitary sewers require additional cleaning. The example of the city of Salzburg illustrates the potential savings in connection with sewer cleaning if a selective approach is adopted. Following a strategic change, the sewer cleaning expenses decreased by 60% within a year.
9 citations
11 Jul 2012
5 citations
06 Mar 2014
TL;DR: Instandhaltung der offentlichen Kanalisation zahlt zu den Kernaufgaben eines Kanalisationsunternehmens as discussed by the authors, sind regelmasige Kontrollen erforderlich, welche die Funktionsfahigkeit des systems gewahrleisten sowie einen eventuell er-forderlichen Sanierungsbedarf erheben sollen.
Abstract: Die Instandhaltung der offentlichen Kanalisation zahlt zu den Kernaufgaben eines Kanalisationsunternehmens. Um Informationen zum Zustand des Kanalsystems zu erhalten, sind regelmasige Kontrollen erforderlich, welche die Funktionsfahigkeit des Systems gewahrleisten sowie einen eventuell erforderlichen Sanierungsbedarf erheben sollen. Zumeist erfolgt die Zustandserfassung entweder direkt durch Begehung oder indirekt durch TV-Inspektion mit fahrbarem Kamerawagen. Alternativ zur herkommlichen TV-Inspektion stehen aber auch andere Inspektionsmethoden zur Verfugung, z. B. mittels elektronischen Spiegels.
4 citations
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TL;DR: A framework that uses deep convoluted neural networks (CNNs) to classify multiple defects in sewer CCTV images to improve the speed, accuracy, and consistency of sewer defect reporting is presented.
174 citations
TL;DR: Due to the difficulty to discriminate the defects, the low-level defect classification accuracy still needs improvements, but the proposed network with hierarchical classification also demonstrated superior performance over traditional approaches.
110 citations
TL;DR: A brief review of the recent research accomplishments in the field of design, maintenance, life-cycle management, and optimisation of structures and infrastructures reported in papers published in Structure and Infrastructure Engineering (SIE) during the period 2005-2011 can be found in this paper.
Abstract: The optimal decisions to maintain or improve the reliability and functionality of structures and infrastructure systems can only be achieved through proper integrated management planning in a life-cycle comprehensive framework. Structure and Infrastructure Engineering (SIE) is an international journal dedicated to recent advances inmaintenance, management, and life-cycle performance of a wide range of infrastructures. The purpose of this article is to provide a brief review of the recent research accomplishments in the field of design, maintenance, life-cycle management, and optimisation of structures and infrastructures reported in papers published in SIE during the period 2005–2011. The papers are categorised under main topics and very briefly discussed.
95 citations
TL;DR: A new risk assessment model is developed to prioritize sewer pipes inspection using Bayesian Networks (BNs) as a probabilistic approach for computing probability of failure and weighted average method to calculate the consequences of failure values.
91 citations
Norwegian University of Science and Technology1, University of Lyon2, Swiss Federal Institute of Aquatic Science and Technology3, SINTEF4, Delft University of Technology5, University of Tehran6, University of Los Andes7, RWTH Aachen University8, University of Coimbra9, Pontifical Xavierian University10
TL;DR: Sewer asset management gained momentum and importance in recent years due to economic considerations, since infrastructure maintenance and rehabilitation directly represent major investments as discussed by the authors. But it is still a relatively new area.
Abstract: Sewer asset management gained momentum and importance in recent years due to economic considerations, since infrastructure maintenance and rehabilitation directly represent major investments. Becau...
70 citations