Abstract

This research report addresses the current uncertainties regarding the technical service life and aging behavior of the most common sewer rehabilitation method, Cured-in-Place Pipe (CIPP) lining. The goal of this study is to develop a robust data foundation for a CIPP liner survival curve for use in aging models. The methodological approach includes (i) a literature review, (ii) interviews with sewer rehabilitation experts, and (iii) an analysis of data from Berliner Wasserbetriebe to create an updated and suitable data basis for the calibration of survival curves. The literature review and expert interviews predominantly estimate the service life of CIPP liners to exceed 50 years. However, the study also reveals that this lifespan is influenced by numerous factors and that there is a lack of reliable data. Further investigations of long-used CIPP liners are therefore essential. The installation process, particularly the curing phase, has been identified as the primary factor contributing to defects and deficiencies in CIPP liners. Standardizing damage assessment and condition evaluation for liner-specific defects, as well as establishing non-destructive inspection methods, is necessary to improve the understanding of aging behavior in the future. Recommendations include improving data collection during the operation, installation, and removal of CIPP liners, enhancing quality assurance during installation, investigating the impact of damage on service life, and promoting knowledge exchange among operators.

Abstract

Addressing Europe's current challenges of aging sewer networks, the presented research focuses on the uncertainties in service life and aging behavior of the most used renovation technique, Cured in Place Pipe (CIPP) lining. Examining its aging behavior, common defects and deficiencies were analyzed through literature review and expert interviews. The findings influenced the proposition of a calibration setting for a deterioration model using survival curves. Identified defects stress the need for precise installation and curing processes. The study recommends a thorough review of the initially specified 50-year service life, acknowledging uncertainties during the installation process.

Miehe, U. , Wicke, D. , Sauter, D. , Brunsch, A. , Nydrioti, I. (2019): Compliance of combined nature-based and engineered systems with European water reuse regulations.

In: 12th IWA International Conference on Water Reclamation and Reuse. Berlin, Germany. 16-20 June 2019

Abstract

Direct addition of powdered activated carbon (PAC) to the inlet of a deep bed filter represents an energy- and space-saving option to remove organic micropollutants (OMPs) during advanced wastewater treatment or drinking water purification. In this lab-scale study, continuous dosing, preconditioning a filter with PAC and combinations thereof were investigated as possible dosing modes with respect to OMP adsorption efficiency. Continuous dosing resulted in decreasing effluent concentrations with increasing filter runtime due to adsorption onto accumulating PAC in the filter bed. Approximately constant removal levels were achieved at longer filter runtimes, which were mainly determined by the dose of fresh PAC, rather than the total PAC amount embedded. The highest effluent concentrations were observed during the initial filtration stage. Meanwhile, preconditioning led to complete OMP adsorption at the beginning of filtration and subsequent gradual OMP breakthrough. PAC distribution in the pumice filter was determined by the loss on ignition of PAC and pumice and was shown to be relevant for adsorption efficiency. Preconditioning with turbulent upflow led to a homogenous PAC distribution and improved OMP adsorption significantly. Combining partial preconditioning and continuous dosing led to low initial effluent concentrations, but ultimately achieved concentrations similar to filter runs without preconditioning. Furthermore, a dosing stop prior to the end of filtration was suitable to increase PAC efficiency without affecting overall OMP removals.

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