Wassergefaehrdung durch undichte Kanaele - Erfassung und Bewertung. T. 2: Untersuchungen zur Erfassung und Bewertung undichter Kanaele im Hinblick auf die Gefaehrdung des Untergrundes. Bd. B Untersuchungen der Arbeitsgruppe Berlin. Abschlussbericht

The project provides results from case studies on sewers carrying mainly domestic wastewater and exhibiting different types and categories of damage at the bottom, the sides and the top of the cross section of the pipe. The condition of the underlying soil was characterized by sediments of differing permeability, ranging from good to poor, with groundwater levels of less than 50 cm to as much as 500 cm below the pipe's bottom. Using indicator parameters, wastewater constituents were detected in the immediate vicinity of dage of categories 0 - 2. Infiltration is limited to a zone only a few decimetres thick, so that the occurrence of environmentally relevant concentrations is assumed to be mainly confined to the damage categories mentioned. Nevertheless, such contamination limits the multifunctional uses of excavated soil in sewer reconstruction. A recommendation for sewer repair practice is that in addition to damage necessitating immediate action, the focus in damage repair should primarily be on categories 0, 1, and 2 damage state occurring at the bottom of the pipe. Priority should be given to the repair of sewers located in areas where the subsoil consists of permeable sediments with groundwater levels of less than 100 cm, and carrying wastewater containing hazardous substances in spite of the required pretreatment. (orig.)Available from TIB Hannover: QN 150(2B)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman