Time filter

Source Type


Nason P.,Lulea University of Technology | Johnson R.H.,U.S. Geological Survey | Neuschutz C.,NIRAS | Alakangas L.,Lulea University of Technology | Ohlander B.,Lulea University of Technology
Journal of Hazardous Materials | Year: 2014

Novel solutions for sulfide-mine tailings remediation were evaluated in field-scale experiments on a former tailings repository in northern Sweden. Uncovered sulfide-tailings were compared to sewage-sludge biosolid amended tailings over 2 years. An application of a 0.2. m single-layer sewage-sludge amendment was unsuccessful at preventing oxygen ingress to underlying tailings. It merely slowed the sulfide-oxidation rate by 20%. In addition, sludge-derived metals (Cu, Ni, Fe, and Zn) migrated and precipitated at the tailings-to-sludge interface. By using an additional 0.6. m thick fly-ash sealing layer underlying the sewage sludge layer, a solution to mitigate oxygen transport to the underlying tailings and minimize sulfide-oxidation was found. The fly-ash acted as a hardened physical barrier that prevented oxygen diffusion and provided a trap for sludge-borne metals. Nevertheless, the biosolid application hampered the application, despite the advances in the effectiveness of the fly-ash layer, as sludge-borne nitrate leached through the cover system into the underlying tailings, oxidizing pyrite. This created a 0.3. m deep oxidized zone in 6-years. This study highlights that using sewage sludge in unconventional cover systems is not always a practical solution for the remediation of sulfide-bearing mine tailings to mitigate against sulfide weathering and acid rock drainage formation. © 2014 Elsevier B.V.

Simonsen R.,Value Creating Construction Processes | Thyssen M.H.,NIRAS | Sander D.,Grontmij
22nd Annual Conference of the International Group for Lean Construction: Understanding and Improving Project Based Production, IGLC 2014 | Year: 2014

Management concepts tend to fade away within a relatively short period of time. After a few years the news value declines, the "gurus" disappear, difficulties in realizing the expected gains are recognized, and new management concepts take over. This paper brings attention to the simple question: How is it possible to sustain interest in Lean Construction? Drawing on literature describing the typical life-cycle of management concepts, the journey of Lean Construction and Lean Construction Institute (LCI) in Danish construction is used as a case. LCI Denmark (LCI-DK) was established in 2002 as the first chapter outside of the USA and may therefore be ahead in regards of concept life-cycle to other LCI chapters around the world. It is argued that a revitalization is needed in Denmark if Lean Construction is to overcome the typical life-cycle of other previous management concepts. This leads to a discussion of implementation barriers and challenges to keeping Lean Construction alive, and how to overcome them. The aim is to spur a discussion that may benefit all who are struggling with implementation barriers or find themselves in a post-interest era.

Wildenberg M.,GLOBAL 2000 | Bachhofer M.,FCMappers.net | Isak K.Q.,NIRAS | Skov F.,University of Aarhus
Intelligent Systems Reference Library | Year: 2014

A halt in loss of biodiversity is an important issue in conservation management across Europe. As landscapes tend to be perceived as a combination of natural and social elements, and people’s values and attitudes, research supporting conservation management is dealing with landscapes as socio-ecological systems. As part of ALTER-Net, we applied FCM to five cases and subsequently evaluated the approach by means of a SWOT framework. This examined the strengths and weaknesses of, and the opportunities and threats to FCM when applied as a tool in conservation management. © Springer-Verlag Berlin Heidelberg 2014.

Kjaer L.L.,Technical University of Denmark | Host-Madsen N.K.,NIRAS | Schmidt J.H.,2. 0 LCA Consultants | McAloone T.C.,Technical University of Denmark
Sustainability (Switzerland) | Year: 2015

An increasing number of companies are expanding their environmental impact reduction targets and strategies to include their supply chains or whole product life cycles. In this paper, we demonstrate and evaluate an approach, where we used a hybrid Environmental Input-Output (EIO) database as a basis for corporate and product environmental footprint accounts, including the entire supply chain. We present three cases, where this approach was applied. Case study 1 describes the creation of total corporate carbon footprint accounts for three Danish regional healthcare organisations. In case study 2, the approach was used as basis for an Environmental Profit and Loss account for the healthcare company, Novo Nordisk A/S. Case study 3 used the approach for life cycle assessment of a tanker ship. We conclude that EIO-based analyses offer a holistic view of environmental performance, provide a foundation for decision-making within reasonable time and cost, and for companies with a large upstream environmental footprint, the analysis supports advancing their sustainability agenda to include supply chain impacts. However, there are implications when going from screening to implementing the results, including how to measure and monitor the effect of the different actions. Thus, future research should include more detailed models to support decision-making. © 2015 by the authors.

Frandsen R.P.,Technical University of Denmark | Eigaard O.R.,Technical University of Denmark | Poulsen L.K.,NIRAS | Torring D.,Danish Shellfish Center | And 3 more authors.
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2015

Dredging blue mussels (Mytilus edulis) and thus removing structural elements, inducing resuspension of sediment as well as reducing filtration capacity, will inevitably affect the ecosystem. The study demonstrates that the impacts of fishing can be reduced through gear developments. A new light dredge was tested on commercial vessels using two different experimental setups. First, a twin haul experiment tested the standard gear (i.e., a Dutch dredge) against the light dredge by fishing the two gears side by side onboard the same vessel. Second, a single dredge experiment tested the absolute performance of the two gears by fishing in areas with a known blue mussel density. Results from the twin haul experiment demonstrate that the weight of sediment retained in the gear per square metre fished is 49% less in the light dredge compared with the Dutch dredge which will reduce resuspension of sediment at the surface. Also, the drag resistance of the light dredge was significantly less (177.1 vs. 202.7kgm-1). In the twin haul experiment no significant difference was found in the catch per unit effort (CPUE) of the two gears. The single dredge experiment, on the other hand, demonstrated a significant increase in CPUE exceeding 200% when using the light dredge. Seafloor tracks made by the two dredges could not be distinguished by use of side-scan sonar and the tracks were still detectable 2months after fishing. It was concluded that replacement of the Dutch dredge with the light dredge would reduce the impact of the fishery on the ecosystem by (i) reducing resuspension of sediment, (ii) reducing fuel consumption, and (iii) potentially reducing energy transfer to the sediment through a reduced gear drag resistance. A potential increase in catch efficiency may reduce the area affected. Fishing with the light dredge is discussed in relation to management of Natura 2000 sites. © 2014 John Wiley & Sons, Ltd.

Discover hidden collaborations