Helge Brattebø

Carbon emissions of infrastructure development.

Identifying strategies for reconciling human development and climate change mitigation requires an adequate understanding of how infrastructures contribute to well-being and greenhouse gas emissions. While direct emissions from infrastructure use are well-known, information about indirect emissions from their construction is highly fragmented. Here, we estimated the carbon footprint of the existing global infrastructure stock in 2008, assuming current technologies, to be 122 (-20/+15) Gt CO2. The average per-capita carbon footprint of infrastructures in industrialized countries (53 (± 6) t CO2) was approximately 5 times larger that that of developing countries (10 (± 1) t CO2). A globalization of Western infrastructure stocks using current technologies would cause approximately 350 Gt CO2 from materials production, which corresponds to about 35-60% of the remaining carbon budget available until 2050 if the average temperature increase is to be limited to 2 °C, and could thus compromise the 2 °C target. A promising but poorly explored mitigation option is to build new settlements using less emissions-intensive materials, for example by urban design; however, this strategy is constrained by a lack of bottom-up data on material stocks in infrastructures. Infrastructure development must be considered in post-Kyoto climate change agreements if developing countries are to participate on a fair basis.

Sustainable management of demolition waste*/ an integrated model for the evaluation of environmental, economic and social aspects

A model is presented for evaluating waste management systems for their contribution to a sustainable development, including environmental, economic and social aspects. The model was tested in a case-study, where groups of long-term unemployed people were offered both education on environmental issues and practical work with the recovery and recycling of building and demolition waste as a form of vocational development. Application of the suggested model revealed the overall effects on sustainability of different methods of waste management. In addition, negative aspects of the systems analysed were identified, which led to discussions about possible improved practices within the waste management systems. Two of the waste management systems investigated (the recycling of steel and re-use of sanitary porcelain) showed a potential contribution to sustainable development in all of the aspects studied. Preparing bricks for re-use showed the largest potential for eco-efficiency, but had negative effects on sustainability from the social perspective of health and the working environment. The possibility of further use of the model and the remaining obstacles to such analyses are discussed. One observation is that the data collection needed to perform this kind of sustainability analysis is resource-demanding, and that it would therefore be better to identify a smaller number of key indicators.

Combined MFA‐LCA for Analysis of Wastewater Pipeline Networks

Summary 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.

Ion exchange for the removal of humic acids in water treatment

Abstract The removal of humic substances is today one of the more important objects in Scandinavian water purification technology. The conventional process is coagulation/flocculation/separation. During the last few years one has also got local pilot scale experiences on the ion exchange process, using a macroporous strong base resin. The process removes humic acids effectively, particularly at moderate humic acid concentrations in the water to be treated. The inlet concentration and the bed contact time were of course found to be the most important parameters. In order to minimize the operating costs, one has paid special attention to regeneration routines and an optimum process design. By use of a beds-in-series system and reuse of the regenerant, one may cut the chemical consumption and thus the waste solution production by a factor of 10.35, in relation to the use of one single fixed-bed without regenerant reuse. The waste production for such a system was found to be 1 m 3 when treating 5910 m 3 water with colour 50 mg Pt l −1 . The process is very well suited for automation and continuous effluent quality control, however, one should pay more attention to corrosion problems.

Sewage sludge disposal strategies for sustainable development

ABSTRACT The main objective of the present review is to compare the existing sewage sludge management solutions in terms of their environmental sustainability. The most commonly used strategies, that include treatment and disposal has been favored within the present state‐of‐art, considering existing legislation (at European and national level), characterization, ecotoxicology, waste management and actual routs used currently in particular European countries. Selected decision making tools, namely End‐of‐waste criteria and Life Cycle Assessment has been proposed in order to appropriately assess the possible environmental, economic and technical evaluation of different systems. Therefore, some basic criteria for the best suitable option selection has been described, in the circular economy “from waste to resources” sense. The importance of sewage sludge as a valuable source of matter and energy has been appreciated, as well as a potential risk related to the application of those strategies. HighlightsEnvironmental sustainability in sewage sludge management.Investigation of eco‐innovations in wastewater treatment.Assessment of ecological consequences of sewage sludge disposal.

Dynamic Eco-Efficiency Projections for Construction and Demolition Waste Recycling Strategies at the City Level

In this article we have elaborated a consistent framework for the quantification and evaluation of eco-efficiency for scenarios for waste treatment of construction and demolition (C&D) waste. Such waste systems will play an increasingly important role in the future, as there has been for many years, and still is, a significant net increase in stock in the built environment. Consequently, there is a need to discuss future waste management strategies, both in terms of growing waste volumes, stricter regulations, and sectorial recycling ambitions, as well as a trend for higher competition and a need for professional and optimized operations within the C&D waste industry. It is within this framework that we develop and analyze models that we believe will be meaningful to the actors in the C&D industry. Here we have outlined a way to quantify future C&D waste generation and have developed realistic scenarios for waste handling based on todays actual practices. We then demonstrate how each scenario is examined with respect to specific and aggregated cost and environmental impact from different end-of-life treatment alternatives for major C&D waste fractions. From these results, we have been able to suggest which fractions to prioritize, in order to minimize cost and total environmental impact, as the most eco-efficient way to achieve an objective of overall system performance.

Life cycle assessment of the water and wastewater system in Trondheim, Norway – A case study

This study presents the results from a life cycle assessment (LCA) performed on the water and wastewater system in the city of Trondheim. The objective of the study was to examine the system-wide life cycle environmental impact potentials of operating the citys water and wastewater system, in order to clarify the relative importance of different environmental impact categories and how different elements of the water and wastewater system contribute to these impacts. As the results of this study were used in the planning of a new carbon-neutral urban settlement, the climate change impact was of special interest. Freshwater eutrophication due to the consumption of energy and chemicals was found to be the impact category with the largest contribution to the total environmental impact. In practice, urban water utilities would have to perform a trade-off between the consumption of energy and chemicals and the discharge of pollutants to receiving waters.

LCA for household waste management when planning a new urban settlement

When planning for a new urban settlement, industrial ecology tools like scenario building and life cycle assessment can be used to assess the environmental quality of different infrastructure solutions. In Trondheim, a new greenfield settlement with carbon-neutral ambitions is being planned and five different scenarios for the waste management system of the new settlement have been compared. The results show small differences among the scenarios, however, some benefits from increased source separation of paper and metal could be found. The settlement should connect to the existing waste management system of the city, and not resort to decentralised waste treatment or recovery methods. However, as this is an urban development project with ambitious goals for lifestyle changes, effort should be put into research and initiatives for proactive waste prevention and reuse issues.

Exploring built environment stock metabolism and sustainability by systems analysis approaches

The material and energy metabolism of the built environment stocks can be examined by use of a generic model framework that allows for a dynamic analysis where the stocks quantity, composition and quality are related to the demand for service provided to the population. The stock is classified by use of type-age matrices, according to what are the important functions, age structure and material composition of the stock. A mathematical model is demonstrated for calculating the relationship between annual stock size, annual stock change, past inflows and present outflows. This allows for quantification of the material and energy metabolism, in a system life cycle perspective, and its corresponding economic and environmental performance. Various aspects of the approach are applied to selected built environment stocks in Norway, and this paper documents part of this approach for building stocks and road bridge stocks. Le métabolisme des matériaux de construction et de l’énergie des parcs du cadre bâti peut être étudié en utilisant un modèle générique qui autorise une analyse dynamique dans laquelle la quantité, la composition et la qualité du parc sont liées à la demande de fourniture de services à la population. Une classification du parc est opérée en utilisant des matrices basées sur le type et l’âge des bâtiments, selon ce que sont les fonctions importantes, la structure par âge et la composition des matériaux de construction du parc. Il est procédé à la démonstration d’un modèle mathématique permettant de calculer la relation entre la taille annuelle du parc, l’évolution annuelle du parc, les entrées antérieures et les sorties actuelles. Ceci permet la quantification du métabolisme des matériaux de construction et de l’énergie, dans la perspective du cycle de vie d’un système, et de sa performance économique et environnementale correspondante. Les différents aspects de cette approche sont appliqués à des parcs sélectionnés du cadre bâti norvégien, et cet article documente la partie de cette approche qui concerne les parcs de bâtiments et les parcs de ponts routiers. Mots clés: parc bâti, cadre bâti, analyse dynamique, performance du cycle de vie, métabolisme, stocks et flux, indicateurs de durabilité

Environmental impact analysis of chemicals and energy consumption in wastewater treatment plants: case study of Oslo, Norway

Wastewater treatment plants, while performing the important function of treating wastewater to meet the prescribed discharge standards, consume energy and a variety of chemicals. This paper analyses the consumption of energy and chemicals by wastewater treatment plants in Oslo over eight years, and their potential environmental impacts. Global warming and acidification were the dominant impacts for chemicals and energy, respectively. Avoided impacts due to usable by-products - sludge, ammonium nitrate and biogas - play a key role in shrinking the environmental footprint of the wastewater plants. The scope for decreasing this footprint by streamlining energy and chemicals consumption is limited, however, considering that over 70% of the impact is accounted for by the eutrophication potential (thanks to the nitrogen and phosphorus which is discharged to the sink) of the treated effluent wastewater.