Time filter
Source Type

Elmegaard B.,Technical University of Denmark | Ommen T.S.,Technical University of Denmark | Markussen M.,DONG Energy | Iversen J.,Grontmij
Energy and Buildings | Year: 2015

District heating may supply many consumers efficiently, but the heat loss from the pipes to the ground is a challenge. The heat loss may be lowered by decreasing the network temperatures for which reason low temperature networks are proposed for future district heating. The heating demand of the consumers involves both domestic hot water and space heating. Space heating may be provided at low temperature in low energy buildings. Domestic hot water, however, needs sufficient temperatures to avoid growth of legionella. If the network temperature is below the demand temperature, supplementary heating is required by the consumer. We study conventional district heating at different temperatures and compare the energy and exergetic efficiency and annual heating cost to solutions that utilize electricity for supplementary heating of domestic hot water in low temperature district heating. This includes direct electric heating and three heat pump solutions applying R134a and R744. The results show that conventional solutions at lowest possible temperature have the highest exergetic efficiency of 28% and lowest annual cost of € 690 for a 159m2 house. The best low temperature system is an R134a heat pump with hot water storage on the district heating side, which reaches 25% exergetic efficiency. © 2015 Elsevier B.V.

Williams C.,Grontmij | Keech R.,ABB | Wheadon R.,Thames Water Utilities
IET Seminar Digest | Year: 2015

Presents a collection of slide covering the following topics: flow metering solution; pressure metering solution; GPRS WITS protocol; and WITS-based SCADA.

Marsden A.,Arup | Manidaki M.,Mott MacDonald Ltd. | Mort S.,Grontmij
Proceedings of Institution of Civil Engineers: Waste and Resource Management | Year: 2012

This paper describes the challenges of delivering a new 730 000 population equivalent wastewater treatment works for Bradford, UK during the asset management period 4 regulatory period. The history of this 100-year-old site is described alongside details of the new infrastructure. Contract delivery mechanisms to use all the knowledge from a competitive tendering arrangement are discussed. The new site incorporates an innovative application of a hydroturbine alongside digestion and combined heat and power engines. The paper describes the energy-saving measures incorporated into the wastewater treatment process providing quantification of generation for the flows and loads treated. The plant provides an average of over 21 MWh of electricity generation per day. Also the approach to designing a cost-effective 55 000 m2 composting area is detailed. Measures to convert existing humus tanks into final settlement tanks are described.

Soors J.,Research Institute for Nature and Forest INBO | Van Haaren T.,Grontmij | Timm T.,Estonian University of Life Sciences | Speybroeck J.,Research Institute for Nature and Forest INBO
Aquatic Invasions | Year: 2013

For the first time, the freshwater oligochaete species Bratislavia dadayi (Michaelsen, 1905) is recorded in Europe. The species was found at three subtidal stations in the Schelde estuary in Belgium, where it was probably introduced from the Americas. We provide an overview of the species' nomenclature, diagnostics, distribution, and ecology. Bratislavia dadayi is one of 11 non-indigenous annelids currently known to occur in the Schelde estuary. © 2013 The Author(s).

Dieperink C.,University Utrecht | Raadgever G.T.,Grontmij | Driessen P.P.J.,University Utrecht | Smit A.A.H.,University Utrecht | Van Rijswick H.F.M.W.,University Utrecht
Water Policy | Year: 2012

The Water Framework Directive has introduced a new governance approach that offers implementing agencies in EU Member States policy discretion to implement ecological ambitions. The aim of this paper was to gain insight into the way regional actors use this discretion and into the rationale behind their behaviour. Our research revealed that in regional implementation processes in the Netherlands, limited ecological ambitions have been framed due to several complications. These complications also occur in other EU Member States. As it might be possible to reduce some of the complications by improving collaboration, exchange and learning between the actors involved, the paper concludes by outlining the important role that communities of practice might play in the implementation process of water policy at the regional level. © IWA Publishing 2012.

Sondergaard B.,Grontmij
INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control | Year: 2014

Noise is a key issue when planning wind farms. The presentation will look into details in noise from wind turbines, noise measurements, noise assessment, including the Danish noise limits for low frequency wind turbine noise, and noise propagation. Development of noise and low frequency noise with the size of the turbines will be discussed. Questions like how far does low frequency noise propagate will be addressed.

Sandersen P.B.E.,Grontmij | Sandersen P.B.E.,Geological Survey of Denmark | Jorgensen F.,Geological Survey of Denmark
Geological Society Special Publication | Year: 2012

Tunnel valleys formed by meltwater erosion underneath the margins of the Pleistocene ice sheets are present in high numbers in the Danish onshore area. The geographical distribution of the buried tunnel valleys is uneven, but when comparing with the substrata lithology we find a large number of valleys in areas dominated by low-permeable sediment and a smaller number in areas with highly permeable substrata. The observations point to the drainage capacity of the ice-sheet substratum as an important factor controlling tunnel-valley formation. Tunnel-valley formation appears to be favoured in areas with low-permeable substrata because meltwater drainage through the sediments is impeded, leading to the formation of a channelized subglacial drainage system. The high transmissivity in areas dominated by permeable substrata facilitates drainage of a part of the meltwater as groundwater. This causes a lowering of the subglacial meltwater pressures, and tunnel-valley formation is less likely. Once formed and filled, the tunnel valleys cause a change of the hydraulic properties of the substratum and if subglacial water pressures underneath a subsequent ice advance are sufficiently high, old tunnel valleys will be prone to reactivation. © The Geological Society of London 2012.

van Hardenbroek M.,University Utrecht | Heiri O.,University Utrecht | Heiri O.,University of Bern | Wilhelm M.F.,Grontmij | Lotter A.F.,University Utrecht
Aquatic Sciences | Year: 2011

The distribution of benthic invertebrates and their subfossil remains was examined within the basin of De Waay, a dimictic, eutrophic lake in the Netherlands. We focused on Chironomidae, but also report the abundances of 11 invertebrate groups that potentially produce chitinous remains that are preserved in the fossil record, although their remains could only be identified at a coarser taxonomic resolution. Most living invertebrates sampled in different seasons were constrained to the littoral zone, with the exception of a few taxa (Ceratopogonidae, Chaoborus flavicans, and Chironomus) that are adapted to low oxygen conditions in the seasonally anoxic profundal zone. In contrast, assemblages of invertebrate remains in lake surface sediments were similar in the entire lake basin, suggesting that considerable numbers of invertebrate remains are transported and redeposited off-shore in Lake De Waay, due to its steep bathymetry. These results indicate that a single sediment sample obtained from the centre of this lake contains subfossil invertebrate remains originating from the entire lake basin. In Lake De Waay, the majority of taxa found in the living assemblages were identified as remains in lake surface sediments, at least for the Chironomidae that could be identified at a similar taxonomic level in living and subfossil assemblages. Of the total 44 chironomid taxa found in Lake De Waay, 35 taxa occurred in the living assemblages and 34 taxa occurred in the subfossil assemblages. Thirty chironomid taxa occurred both as living and subfossil specimens, and on average these 30 taxa represent 94% of the specimens encountered in a sediment sample. Five rare chironomid taxa present as living larvae were not detected in the subfossil assemblages. Conversely, eight rare and four common chironomid taxa were found in subfossil remains, but not in living assemblages. Our results indicate that subfossil assemblages in surface sediment samples provide spatially integrated and representative samples of the living assemblage. However, a combined approach examining both the living benthic invertebrate fauna and invertebrate remains in lake surface sediments will potentially give a more complete and detailed overview of benthic invertebrates in a lake ecosystem than an approach based exclusively on one of these groups. © 2010 The Author(s).

Sampson J.,Water and Environment | Biesta M.,Mouchel | Crapper M.,University of Edinburgh | Hall I.,Grontmij | Shepherd A.,Grontmij
Proceedings of the Institution of Civil Engineers: Engineering Sustainability | Year: 2013

A spreadsheet-based tool for whole-life carbon dioxide accounting of soil remediation projects has been created. The tool carries out whole-life analysis of projects, including supply chain emissions. It was applied to the Glasgow 2014 Commonwealth Games Athletes' Village remediation project, for which a calculated total 'carbon footprint' of 2328t of carbon dioxide equivalent emission (tCO2e) was obtained. This is 71 tCO2e/ha of the site or 13·3 kgCO2e/t whole life of soil treated. These figures are not comparable with those reported for other projects, which have typically not included supply chain emissions. Fuel use was the main contributor to emissions, but the contribution made by staff transport and carbon dioxide embodied in construction plant was also found to be significant. A comparison was made with an excavate and disposal (E&D) approach, which required considerable use of estimation for the hypothetical E&D. However, it was determined that the carbon footprint of E&D may have been 14% higher than the soil washing actually used. It was concluded that fuel efficiency would be key to future reduction of the carbon footprint of remediation projects, that the accounting tool would be useful for ongoing project management, and its application over time could lead to a database of values for optioneering at the process design stage.

Raadgever G.T.,Grontmij | Dieperink C.,Copernicus Institute for Sustainable Development and Innovation | Driessen P.P.J.,Copernicus Institute for Sustainable Development and Innovation | Smit A.A.H.,Copernicus Institute for Sustainable Development and Innovation | van Rijswick H.F.M.W.,University Utrecht
Environmental Science and Policy | Year: 2011

Environmental managers have to deal with many uncertainties in carrying out their jobs. Literature describes several strategies that can be employed to manage these uncertainties, but this is done in a fragmented way. Therefore, this article aims to develop a comprehensive, coherent and empirically sound classification of uncertainty management strategies. The strategies mentioned in literature can be classified into four categories: ignoring uncertainty; knowledge generation; interaction and coping. A case study of the implementation of the Water Framework Directive (WFD) by Dutch water boards was conducted to test whether the identified strategies are employed in practice. The WFD presents the water boards with uncertainties resulting from the requirements to improve water quality and ecology on one hand, while leaving room to adapt those requirements to regional interests, practices and institutions on the other. The case study confirms the empirical soundness of the classification by revealing that many of the uncertainty management strategies in literature are applied in practice as well. However, further research to test the empirical soundness of the classification in other fields of environmental management is required. © 2010 Elsevier Ltd.

Loading Grontmij collaborators
Loading Grontmij collaborators