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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

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. Source

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

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. Source

Susman G.,Buro Happold | Susman G.,Brunel University | Dehouche Z.,Brunel University | Hassan R.,Grontmij
Proceedings of Institution of Civil Engineers: Energy

This work presents results from a cooling system in a UK office building served by two no. 241.3 kW chillers and two tanks containing hydrated salt phase-change material. The tanks are intended to save electrical energy by pre-cooling chiller return water. Accumulated heat is dicharged at night when chiller coefficients of performance increase. Chiller power and system temperatures were monitored for 6 days. The electrical energy required for an identical tankless system was calculated using tank temperatures and chiller performance curves for varying ambient temperatures. Differential scanning calorimetry results were used to calculate the tanks' thermal capacity. The system incurred a 687 kWh energy cost (10.6% of total cooling energy), as compared to a tankless system, because night chiller and pump power outweighed daytime savings. Only 28% of the tank capacity was utilised because insufficient heat was discharged to the chilled water at night. This is partly because the freeze temperature of the phase-change material appears too low for sufficient heat rejection to the chilled water. Source

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

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). Source

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

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. Source

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