LCCA of wastewater pipeline network in Oslo

All wastewater utilities have a primary obligation towards their customers to maintain the level of service and improve it wherever and whenever possible. The secondary goals are to rejuvenate the system and stem the decline in capital value. With the private sector increasingly foraying into the water and wastewater sector, long-run profitability is also becoming one of the considerations in decision-making. In Oslo, in the period 1991-2006, the operation and maintenance expenses on wastewater pipelines were higher than the investments, the network aged and its capital value plummeted. Changes in approach are very much necessary. One would ponder over whether the pipelines should be depreciated over a longer period than the 40 years which is adopted now? Should the economic method be replaced by a more engineering-based method, whereby the pipes are assessed ‘on merit’ – on the basis of their service lives? There are numerous issues and a good decision will ease the road ahead. This paper, using Life Cycle Costing Analysis and scenarios therein, looks at how the Oslo water/wastewater utility could strike a balance between expending on O&M, investing in upgrading the network, and decelerating the ageing of the network while augmenting the capital value, and what is the best attainable set of targets they could aim for, at the end of the next 20 years. A vis -a-vis study of the engineering and economic approaches, is attempted in this paper.