Prioritering av förnyelseområden VA-nät : Värderingsmodell för optimering av långsiktig kundservice baserad på driftstörningsstatistik, öppen programvara och anläggningsdata

Sammanfattning: The water and sewage system is classified as a necessary social function in Sweden. In order to obtain a functional system with acceptable amounts of malfunctions, continuous maintenance and renewal by replacing existing pipes where life expectancy is considered exhausted. The rate of change can be defined as the renewal. The majority of Sweden's pipeline networks were built in the 60s and 70s, and the renewal pace has remained low since then, in relation to the service life of the pipeline. If the renewal pace is too low for a long period of time, future difficulties can arise because pipes ages faster than the renewal pace. Many municipalities in Sweden have maintenance and renewal plans to achieve goals such as increasing/maintaining customer service for water and sewage system. At the renewal planning for each municipality, a tool published by Svenskt Vatten can be used to estimate the general renewal need for the entire municipality. The tool is for instance based on year of installation, pipe material and length of the pipe length in the system. A general renewal need provides a good overall measure of the municipality's need, but it does not make it easier to prioritize internal renewal. The purpose of this thesis was to provide a method for determining where the resources in a municipality should be placed in order to maintain or increase customer service regarding water services connected to wiring networks. The method is based on a prioritization that was carried out by combining customer service and the water management system's condition. In this study, the method of prioritization was applied in a case study at the municipality of Boden. To identify the condition of the pipe network, several different influencing factors have been analysed to identify critical areas. An area-based valuation model has been developed based on a Swedish valuation model from 2007. The results showed correlation between leakage frequency on the water pipeline network and various influencing factors such as soil types, pipe materials and construction year. A method has been developed to help municipalities to compile the influencing factors that are critical to that particular municipality based on the information available in the municipality. A methodology for how municipalities can compile operational disturbances and illustrate these with a map-based independent database have also been developed. An area-based valuation model was developed to enable assessment of customer service independent municipality and its resources. In this tool, the municipality itself is able to determine the importance of parameters. The valuation of customer service was based on the number of customers affected, building, length of the pipes and malfunctions reports. However, these parameters are not linked to synergy or critical wires based on a social perspective. The valuation model should therefore be supplemented with an assessment of the consequences of interference. A conclusion from the case study was that the entire municipality's main management network showed increased trends in leakage rates. Trends also showed that customer satisfaction in the majority of areas is falling over time, based on results from site evaluation. A recommendation was made to the municipality in the case study in which areas renewal should be prioritized over the coming five years based on the valuation of customer service and management condition.