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Oslo's wastewater pipeline network has an aging stock of concrete, steel, and polyvinyl chloride (PVC) pipelines, which calls for a good portion of expenditures to be directed toward maintenance and investments in rehabilitation. The stock, as it is in 2008, is a direct consequence of the influx of pipelines of different sizes, lengths, and materials of construction into the system over the years. A material flow analysis (MFA) facilitates an analysis of the environmental impacts associated with the manufacture, installation, operation, maintenance, rehabilitation, and retirement of the pipelines. The forecast of the future flows of materials-which, again, is highly interlinked with the historic flows-provides insight into the likely future environmental impacts. This will enable decision makers keen on alleviating such impacts to think along the lines of ecofriendlier processes and technologies or simply different ways of doing business. Needless to say, the operation and maintenance phase accounts for the major bulk of emissions and calls for energy-efficient approaches to this phase of the life cycle, even as manufacturers strive to make their processes energy-efficient and attempt to include captive renewable energy in their total energy consumption. This article focuses on the life cycle greenhouse gas emissions associated with the wastewater pipeline network in the city of Oslo.

No abstract

Any saturated urban wastewater pipeline network has an ageing mix of pipelines of different lengths, diameters and materials of construction. Each of these pipe-lengths has its own life-cycle which encompasses the material production and pipe fabrication, installation, operation and maintenance during the use phase, rehabilitation and repair and finally retirement from service. An analysis of the inflows of materials and energy into the network and the corresponding outflows, facilitates the determination of the environmental impacts associated with the life-cycle stages of the pipeline network, and an examination of how the contributions of each of these phases to the whole, changes as the network ages and progresses towards saturation. The forecast of the future flows of materials which again, is highly interlinked with the historic flows provides insight into the likely future environmental impacts. The authors, in this paper, present a general methodology which can be applied with some tailor-making, to the analysis of any wastewater pipeline network in general. The methodology is then applied to the pipeline network in the city of Oslo, and the results thereof presented towards the end of the paper.

No abstract