Testing different rehabilitation options in the drinking water pipeline network in Oslo using DYNAMIC METABOLISM MODEL (DMM) / Utprøving av forskellige rehabiliteringsopsjoner i Oslos drikkevannledningsnettverket ved bruk av den dynamisk-metabolism-modellen (DMM)

This study is being carried out at the behest of Oslo VAV (Vann og Avløpsetaten; Water and Sanitation Utility) personnel, as an additional test with the Dynamic Metabolism Model (DMM) developed at NTNU in Trondheim. It considers rehabilitation of drinking water pipelines as the only intervention in the entire system; and tests for different rehabilitation rates; 1 %, 1.25 %, 1.5 %, 2 %, 2.25 % and 2.5 %. A range of indicators for the water distribution sub-system are calculated for the study period 2013–2043. Of all the indicators for the entire system, calculated automatically by the DMM for these different rehabilitation rates, four are selected for tabular and graphical representation in this article. A rise in the rehabilitation rate from 1 % to 2.5 % has a conspicuous impact on the relative value of the GHG emissions per cubic metre water demand in 2043 – it falls from 0.822 to 0.772. The relative value of the total energy consumed in the entire system per capita in the year 2043 drops with a rise in the rehabilitation rate (0.86 for 1 % to 0.796 for 2.5 %). It will however not be possible to say what the optimum rehabilitation rate to be pursued is, unless one knows what are the indicators of relevance the utility wishes to work with and how they rank/weight these. It is a matter here of considering indicators of different types – functional (rehabilitation rate, leakage rate), environmental (GHG emissions, acidification etc., on a per-capita basis), physical (possibly pipeline material mass per capita, if lightening the network in this regard could be an objective) and economic (capital costs and O&M expenses expressed as appropriate indicators). Setting targets and benchmarks to be achieved in the case of these indicators would also be useful.