Abstract

Pipelines account for the lion's share of the lifetime costs of any typical urban wastewater collection. While the deterioration of pipeline is the obvious "frontline‟ reason to adopt Asset Management practices, a more overarching driver is the need to gravitate towards sustainable development and set short and long term objectives encompassing economic, social and environmental goals. Optimising the expenses and providing the required levels of service to customers are the twin targets of wastewater utilities. Oslo Vann og Avløpsetaten – the water/wastewater utility in the Norwegian capital, considered as case study in this paper, is sprucing up its data-bank, rightly realising that a very effective information management system is the spine of Asset Management.

Abstract

The city of Oslo is evaluating strategies for the selection of appropriate materials for the pipelines and manholes of its wastewater network. The overarching motive is to minimise construction-related failures over the system lifetime and also ensure that it is able to avert flooding events. This paper analyses the blockage records of the last 16 years (1991–2006) in the wastewater pipeline network of Oslo. For the purpose of the analysis, the pipeline stock is categorised on the basis of pipe diameter, material of fabrication, slope and age. Proneness to blockages is studied and attempts are made to correlate the same to the size, material, slope and age. The analyses performed confirm that older and small diameter sewage pipelines made of concrete, laid almost horizontal to the ground surface are the high-priority candidates, and more importantly enables one to compare among the different categories and classes of pipelines.