scholarly journals HYDRODYNAMIC ANALYSIS OF SLUDGE DUMPED IN COASTAL WATERS

1972 ◽  
Vol 1 (13) ◽  
pp. 121
Author(s):  
Billy L. Edge
Keyword(s):  
Dredged Material ◽  
Transport Mechanisms ◽  
Environmental Pressures ◽  
Hydrodynamic Analysis ◽  
Fine Grained ◽  
Land Disposal ◽  
Physical Forces ◽  
Maintenance Dredging ◽  
Disposal Problem ◽  
Wastewater Sludges

Due to increased environmental pressures, there is a rapidly growing tendency to shift from traditional land disposal of dredged material to offshore or ocean disposal. The quantities of such materials are quite large, resulting in a very serious disposal problem. For example, maintenance dredging alone produces approximately six million cubic yards of material annually in Charleston Harbor. Existing techniques are reasonably adequate to describe the transport and settling characteristics of coarse, sandy dredge materials discharged from barges or hopper dredges at sea. However, such approaches need to be modified to describe the transport of fine-grained clay and silt materials. This material constitutes a significant portion of the dredged material resulting from both new harbor and channel construction and maintenance dredging along the coast of the Carolinas and Georgia. These fine-grained materials are subject to many additional physical forces as well as chemical phenomena, e.g., flocculation, salinity and temperature variations, etc. A hydrodynamic model for fine-grained dredged material has been developed which considers many of these forces. It is also applicable for describing the transport mechanisms associated with barge disposal of wastewater sludges from municipal and industrial sources. The results of the model indicate what discharge strategies are necessary for placing the sludge at a desired location or depth with a predetermined concentration.

Emissions of porewater compounds and gases from the subaquatic sediment disposal site “rodewischhafen”, hamburg harbour

1998 ◽  
Vol 37 (6-7) ◽  
pp. 87-93 ◽  
Author(s):  
M. Kussmaul ◽  
A. Groengroeft ◽  
H. Koethe
Keyword(s):  
Water Surface ◽  
Disposal Site ◽  
Dredged Material ◽  
Water Fluxes ◽  
Gas Emissions ◽  
Fine Grained ◽  
Deposit Surface ◽  
Groundwater Samples ◽  
High Concentrations ◽  
Mud Deposit

In the year 1993 a confined and unused harbour basin was used to store 290,000 m3 of fine-grained dredged material from Hamburg harbour. About 70% of the deposit surface was water covered. The edge areas were above the water table and covered with reed. Emissions of dissolved compounds into the groundwater, as well as surface gas emissions were measured from 1994 to 1996. As indicators for water fluxes from the deposit we used NH4+ and HCO3− because of their high concentrations in mud porewater in comparison to groundwater. The average concentrations of NH4+ and HCO3− in the porewater increased during 2 years from 85 to 250 mg NH4+ 1−1 and from 2.0 to 3.1 g HCO3− 1−1, while the groundwater samples showed constant values of 8 mg NH4+ 1−1 and 0.7 g HCO3− 1−1. Furthermore, the average gas emissions over the water surface were 3.2 g CH4 m−2 d−1 and 0.8 g CO2 m−2 d−1. In contrast, no methane and 3.0 g CO2 m−2 d−1 were emitted from land areas. The results indicated, that there were no significant emissions of mud porewater compounds into the groundwater but high CH4-emissions over the water covered surface of the mud deposit.

Macrofaunal recolonisation following the intertidal placement of fine-grained dredged material

2009 ◽  
Vol 168 (1-4) ◽  
pp. 499-510 ◽  
Author(s):  
Stefan George Bolam ◽  
Jon Barry ◽  
Michaela Schratzberger ◽  
Paul Whomersley ◽  
Mike Dearnaley
Keyword(s):  
Dredged Material ◽  
Fine Grained

scholarly journals Advances in Maintenance of Ports and Waterways: Water Injection Dredging

2021 ◽  
Author(s):  
Alex Kirichek ◽  
Katherine Cronin ◽  
Lynyrd de Wit ◽  
Thijs van Kessel
Keyword(s):  
Water Injection ◽  
Fluid Mud ◽  
Density Currents ◽  
Fine Grained ◽  
Sediment Bed ◽  
Port Authorities ◽  
Monitoring Tools ◽  
Nautical Bottom ◽  
Maintenance Techniques ◽  
Maintenance Dredging

The main objective of this chapter is to demonstrate developments in port maintenance techniques that have been intensively tested in major European ports. As regular port maintenance is highly expensive, port authorities are considering alternative strategies. Water Injection Dredging (WID) can be one of the most efficient alternatives. Using this dredging method, density currents near the bed are created by fluidizing fine-grained sediments. The fluidized sediment can leave the port channels and be transported away from the waterways via the natural force of gravity. WID actions can be successfully coupled with the tidal cycle for extra effectiveness. In addition, WID is combined with another strategy to reduce maintenance dredging: the nautical bottom approach, which enables the vessel to navigate through the WID-induced fluid mud layer. The nautical bottom approach uses the density or the yield stress of sediment to indicate the navigability after WID rather than the absolute depth to the sediment bed. Testing WID-based port maintenance requires thorough preparation. Over the years modeling and monitoring tools have been developed in order to test and optimize WID operations. In this chapter, the application of the recently developed tools is discussed.

Placing and Capping Fine-Grained Dredged Material

Dredging '02 ◽  
2003 ◽  
Author(s):  
Mark T. Otten ◽  
Gregory L. Hartman
Keyword(s):  
Dredged Material ◽  
Fine Grained

scholarly journals FORMATION OF STRUCTURE OF HOOKS OF LOADING LIFTS IN CONDITIONS OF SHS

2020 ◽  
pp. 123-128
Author(s):  
Cереда Б. ◽  
Волох В.
Keyword(s):  
High Temperature ◽  
Transport Mechanisms ◽  
Rational Structure ◽  
Temperature Synthesis ◽  
Metallurgical Production ◽  
Structure Control ◽  
Fine Grained ◽  
High Temperature Synthesis ◽  
Steel 20 ◽  
Different Diameters

The article deals with the formation of the structure of hoists for lifting cranes in order to prevent the development of cracks by forming the structure of steel 20 by treatment in the conditions of self-propagating high-temperature synthesis (SHS) to obtain fine-grained ferrite-perlite structure. The conducted researches allow to form a rational structure of steel to exclude the development of cracks in dangerous sections of lifting hooks of hoisting and transport mechanisms working in the shops of metallurgical production. The method of structure control after SHS is developed taking into account the influence of different diameters of hooks.

scholarly journals Fly Ash

2017 ◽  
Author(s):  
Anna Wilhelmsson
Keyword(s):  
Fly Ash ◽  
Environmental Protection Agency ◽  
High Water ◽  
Crushed Rock ◽  
Filling Materials ◽  
Dredged Materials ◽  
Land Disposal ◽  
Maintenance Dredging ◽  
Port Structures ◽  
New Framework

Over the next few years, more than one million m3 of contaminated sediments, with a muddy texture, high water ratio and low strength, shall be dredged annually in the development of ports and maintenance dredging of navigable waterways in Sweden. Dumping at sea is limited since the dredged materials are contaminated. Land disposal requires transports and land area and is thus high in costs. In the construction of new port areas, large volumes of crushed rock, etc. are normally used as construction filling materials. These materials can be replaced by stabilised and solidified dredged materials, with modified geotechnical properties. The method of stabilising / solidifying (s/s) contaminated dredged materials has been used internationally for a long period of time and in more recent years, even in the Nordic countries. In Sweden, for instance, the Port of Gävle and the Port of Oxelösund have received permissions to reuse s / s-treated contaminated dredged materials in the port structures. The Municipality of Oskarshamn have applied for permit and permission are expected in autumn 2012. The Municipality of Oskarshamn will receive funding from the Swedish Environmental Protection Agency for remediating the polluted sediments within the harbor basin. Reuse of the stabilized / solidified masses in a geotechnical structure is supported by the new Framework Directive (2008/98/EC) on waste where great emphasis is placed on recycling. Within some of the projects mentioned the potential of using fly ash as a complementary binder has been investigated. In the presentation some of the most interesting results will be presented.

scholarly journals 3D HYDRODYNAMIC MODELING TO CHARACTERISE THE BEHAVIOUR OF THE DISPOSAL OF DREDGED MATERIAL USING A VERTICAL TREMIE PIPE

2018 ◽  
pp. 26
Author(s):  
Siviwe Mabija
Keyword(s):  
Case Studies ◽  
Hydrodynamic Modeling ◽  
Dredged Material ◽  
Mixing Zone ◽  
Regulatory Standard ◽  
Form Part ◽  
Maintenance Dredging

Dredge plume modelling forms an integral part of the supporting studies for EIA applications for both capital and maintenance dredging projects. The behaviour of dredge plumes is function of many variables, many of which are unknown at the time of undertaking the studies. As such engineering judgment, previous project experience (including engaging dredging contractors) and available literature form part of the tools used to characterize the behaviour of dredge plumes. This paper summarises two case studies where underwater disposal (using a vertical tremie pipe) of dredge material from a cutter section (CSD) was simulated in order to meet the regulatory standard at the edge of mixing zone.

scholarly journals The Fate of Nitrogen in Dredged Material Used for Tidal Marsh Restoration

2021 ◽  
Vol 9 (8) ◽  
pp. 849
Author(s):  
Lorie W. Staver ◽  
Jeffrey C. Cornwell ◽  
Nicholas J. Nidzieko ◽  
Kenneth W. Staver ◽  
J. Court Stevenson ◽  
...  
Keyword(s):  
Organic Matter ◽  
Chesapeake Bay ◽  
Tidal Marsh ◽  
Aquatic Vegetation ◽  
Dredged Material ◽  
Submersed Aquatic Vegetation ◽  
Labile Organic Matter ◽  
Marsh Restoration ◽  
Fine Grained ◽  
Tidal Marsh Restoration

Tidal marsh restoration using dredged material is being undertaken in many coastal areas to replace lost habitat and ecosystem services due to tidal marsh loss. The fate of high levels of nitrogen (N) in fine-grained dredged material used as a substrate for marsh restoration is uncertain, but if exported tidally may cause subtidal habitat degradation. In this study, a mass balance was developed to characterize N fluxes in a two-year-old restored tidal marsh constructed with fine-grained dredged material at Poplar Island, MD, in Chesapeake Bay, and to evaluate the potential impact on the adjacent submersed aquatic vegetation (SAV) habitat. Denitrification and N accumulation in Spartina organic matter were identified as the major sinks (21.31 and 28.5 mg N m−2 d−1, respectively), while tidal export of TN was more modest (9.4 mg N m−2 d−1) and inorganic N export was low (1.59 mg N m−2 d−1). Internal cycling helped retain N within the marsh. Mineralization of N associated with labile organic matter in the dredged material was likely a large, but unquantified, source of N supporting robust plant growth and N exports. Exceedances of SAV water quality habitat requirements in the subtidal region adjacent to the marsh were driven by elevated Chesapeake Bay concentrations rather than enrichment by the marsh.

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