Sofia Lidelöw

Assessing the environmental impact of ashes used in a landfill cover construction.

Large amounts of construction materials will be needed in Europe in anticipation for capping landfills that will be closed due to the tightening up of landfill legislation. This study was conducted to assess the potential environmental impacts of using refuse derived fuel (RDF) and municipal solid waste incineration (MSWI) ashes as substitutes for natural materials in landfill cover designs. The leaching of substances from a full-scale landfill cover test area built with different fly and bottom ashes was evaluated based on laboratory tests and field monitoring. The water that drained off above the liner (drainage) and the water that percolated through the liner into the landfill (leachate) were contaminated with Cl(-), nitrogen and several trace elements (e.g., As, Cu, Mo, Ni and Se). The drainage from layers containing ash will probably require pre-treatment before discharge. The leachate quality from the ash cover is expected to have a minor influence on overall landfill leachate quality because the amounts generated from the ash covers were low, <3-30l (m(2)yr)(-1). Geochemical modelling indicated that precipitation of clay minerals and other secondary compounds in the ash liner was possible within 3 years after construction, which could contribute to the retention of trace elements in the liner in the long term. Hence, from an environmental view point, the placement of ashes in layers above the liner is more critical than within the liner.

MSWI bottom ash used as basement at two pilot-scale roads: Comparison of leachate chemistry and reactive transport modeling

The recycling of municipal solid waste incineration bottom ash as aggregates for road basement requires assessing the long-term evolution of leachate chemistry. The Dåva (Sweden) and Hérouville (France) pilot-scale roads were monitored during 6 and 10 years, respectively. Calculated saturation indices were combined to batch test modeling to set a simplified geochemical model of the bottom ash materials. A common reactive transport model was then applied to both sites. At Hérouville, pH and the concentration of most elements quickly drop during the first two years to reach a set of minimum values over 10 years. The decrease is less pronounced at Dåva. The evolutions of pH and major element concentrations are fairly well related to the following pH-buffering sequence: portlandite, C-S-H phases or pseudo-wollastonite and, finally, calcite in equilibrium with atmospheric CO(2). Al(OH)(3), barite, ettringite and monohydrocalcite may also control leachate chemistry. Cu release is correctly modeled by DOM complexation and tenorite equilibrium. Temperature has no significant effect on the modeling of leachate chemistry in the range 5-30°C, except at high pH. Effects at road edges and roadside slopes are important for the release of the less reactive elements and, possibly, for carbonation processes.

Techniques for the Stabilization and Assessment of Treated Copper-, Chromium-, and Arsenic-contaminated Soil

Abstract Remediation mainly based on excavation and burial of the contaminated soil is impractical with regard to the large numbers of sites identified as being in need of remediation. Therefore, alternative methods are needed for brownfield remediation. This study was conducted to assess a chemical stabilization procedure of CCA-contaminated soil using iron (Fe)-containing blaster sand (BS) or oxygen-scarfing granulate (OSG). The stabilization technique was assessed with regard to the feasibility of mixing ameliorants at an industrial scale and the efficiency of the stabilization under different redox conditions. The stability was investigated under natural conditions in 1-m3 lysimeters in a field experiment, and the effect of redox conditions was assessed in a laboratory experiment (10 L). The treatments with high additions of ameliorant (8% and 17%) were more successful in both the laboratory and field experiments, even though there was enough Fe on a stochiometric basis even at the lowest addition rates (0.1% and 1%). The particle size of the Fe and the mixing influenced the stabilization efficiency. The development of anaerobic conditions, simulated by water saturation, increases the fraction of arsenic (AsIII) and, consequently, As mobility. The use of high concentrations of OSG under aerobic conditions increased the concentrations of nickel (Ni) and copper (Cu) in the pore water. However, under anaerobic conditions, it decreased the As leaching compared with the untreated soil, and Ni and Cu leaching was not critical. The final destination of the treated soil should govern the amendment choice, that is, an OSG concentration of approximately 10% may be suitable if the soil is to be landfilled under anaerobic conditions. Alternatively, the soil mixed with 1% BS could be kept under aerobic conditions in a landfill cover or in situ at a brownfield site. In addition, the treatment with BS appeared to produce better effects in the long term than treatment with OSG.

Using the Energy Signature Method to Estimate the Effective U-Value of Buildings

The oil crisis of the 1970s and the growing concern about global warming have created an urge to increase the energy efficiency of residential buildings.Space heating and domestic hot water production account for approximately 20% of Sweden’s total energy use. This study examines the energy performance of existing building stock by estimating effective U-values for six single-family houses built between 1962 and 2006. A static energy signature model for estimating effective U-values was tested, in which the energy signature was based on measurements of the total power used for heating and the indoor and outdoor temperatures for each studied house during three winter months in northern Sweden. Theoretical U-values for hypothetical houses built to the specifications of the Swedish building codes in force between 1960 and 2011 were calculated and compared to the U-values calculated for the studied real-world houses. The results show that the increasingly strict U-value requirements of more recent building codes have resulted in lower U-values for newer buildings, and that static energy signature models can be used to estimate the effective U-value of buildings provided that the differences between the indoor and outdoor temperatures are sufficiently large.

Exploring industrialized housebuilders' interpretations of local requirements using institutional logics

Industrialized housebuilding contractors use standardized processes and building systems to improve time and cost efficiency. Recent governmental investigations argue that Swedish local planning authorities’ requirement setting practices stifle the potential for increased industrialization. Yet, no previous research has accounted for the industrialized housebuilders’ perspective. We aim to explore industrialized housebuilders’ interpretations of local requirement setting, using institutional logics to increase the understanding of how structure and human agency influence the emergence of local requirements. Interviews were conducted with representatives of five industrialized housebuilders who together span the Swedish multi-family housing market. Findings indicate that industrialized housebuilders do not perceive intentional local requirement setting as problematic, yet struggle to cope with interpretive local requirement setting. Findings also necessitate distinguishing local requirement setting in the exercise of public authority from local requirement setting in public procurement. The agency structure dualism contributes an understanding of interpretive local requirement setting in the exercise of public authority as an expression of agency and of local requirement setting in public procurement as one of structure. Furthermore, using an institutional logics approach is found to provide an accentuation of human agency and the individual level of analysis that is often absent from construction management research.

Leaching behaviour of copper slag, construction and demolition waste and crushed rock used in a full-scale road construction

The leaching behaviour of a road construction with fayalitic copper slag, recycled concrete and crushed rock as sub-base materials was monitored over ten years. All studied materials used in the road construction, including crushed rock, contained concentrations of several elements exceeding the guideline values recommended by the Swedish EPA for total element concentrations for waste materials used in constructions. Despite that, leaching from the road construction under field conditions in general was relatively low. The leachates from the recycled materials contained higher concentrations of several constituents than the leachates from the reference section with crushed rock. The leaching of the elements of interest (Cr, Mo, Ni, Zn) reached peak concentrations during the second and fourth (Cu) years and decreased over the observation period to levels below the Swedish recommended values. Carbonation of the concrete aggregates caused a substantial but short-term increase in the leaching of oxyanions such as chromate. The environmental risks related to element leaching are highest at the beginning of the road life. Ageing of materials or pre-treatment through leaching is needed prior to their use in construction to avoid peak concentrations. Also, the design of road constructions should be adjusted so that recycled materials are covered with low-permeability covers, which would minimize the exposure to atmospheric precipitation and weathering.

From the Pilot Project to the Mainstream Practice - Learning Explored in Planning and Design of a Low-Energy Quarter☆

Abstract Pilot projects are common platforms for developing/testing construction methods or solutions for e.g. low-energy house-building. Whereas studies report on their technical/engineering outcomes, little is known from a learning perspective. In our study of pilot-project learning, the planning for and assessment of learning from a “low-energy quarter” pilot was explored. In step one, the initiators and the local authority participantswere addressed. The findings of the interviews indicatedthe changed understandings during the pilot of e.g. the planning and design criteria for sustainable building. Although stressed at the pilot outset, it seems that the learning among the stakeholders was not so well documented or systematically evaluated and shared so that the mainstream practice could have been informed or changed.

Comparing Energy Signature Analysis ToCalculated U-values In Wooden Houses InA Cold Climate

In Sweden the housing sector stands for about 40% of the energy usage. About 20% of total energy usage goes to heating and hot tap water. Since 1920, the dominant building technology for single fam ...